
No TEXT global attribute value.
The data set overview can be found at https://space.physics.uiowa.edu/plasmawave/voyager/data/voyager1pwssa/docume nt/FULL1_DS.TXT F. L. Scarf and D. A. Gurnett, A Plasma Wave Investigation for the Voyager Mission, Space Sci. Rev., 21, 289, 1977. https://space.physics.uiowa.edu/voyager/
calibrated Efield for 16 channels
calibrated Efield for 16 channels
calibrated Efield for 16 channels
Telemetry (or instrument) mode, such as CR5A or UV5A
The spacecraft clock
'A Plasma Wave Investigation for the Voyager Mission' F. L. Scarf and D. A. Gurnett, Space Science Reviews, Vol. 21, p. 289, 1977.
The data set overview can be found at https://space.physics.uiowa.edu/plasmawave/voyager/data/voyager2pwssa/docume nt/FULL2_DS.TXT F. L. Scarf and D. A. Gurnett, A Plasma Wave Investigation for the Voyager Mission, Space Sci. Rev., 21, 289, 1977. https://space.physics.uiowa.edu/voyager/
calibrated Efield for 16 channels
calibrated Efield for 16 channels
calibrated Efield for 16 channels
Telemetry (or instrument) mode, such as CR5A or UV5A
The spacecraft clock
'A Plasma Wave Investigation for the Voyager Mission' F. L. Scarf and D. A. Gurnett, Space Science Reviews, Vol. 21, p. 289, 1977.
This data set contains data from the LECP instrument on the Voyager 1 spacecraft. Each record in a file contains 1day (24hour) scanaveraged fluxes and flux uncertainties of electrons in two contiguous energy channels that cover the energy range 2670 keV. The period 2002/001 through 2012/240 includes electrons measured upstream of the termination shock and in the heliosheath up though ~2 days after the heliopause crossing. The Voyager 1 LECP instrument steps through eight, 45 deg fullangle sectors, spending 192 sec in each sector, yielding a full scan through 360 deg every 25.6 min. The LECP scan plane is nearly parallel to RTplane of the heliospheric RTN coordinate system. The electron data are averaged over the seven active sectors S1S7; S8 is behind the sunshield and not included in the average.  Electron channels designated EB01 and EB02  Data have been corrected to remove background due to penetrating cosmic ray ions  Fluxes and uncertainties (one st. dev.) in units: electrons/cm^2ssrMeV  Data are 5point running averages of daily values  Values 9.900e+01 used for missing or nonphysical data  Negative year indicates filled data for the associated doy
This data set contains data from the LECP instrument on the Voyager 2 spacecraft. Each record in a file contains 1day (24hour) scanaveraged fluxes and flux uncertainties of electrons in two contiguous energy channels that cover the energy range 2261 keV. The period 2006/001 through 2018/304 includes electrons measured upstream of the termination shock and in the heliosheath up to heliopause crossing. The voyager 2 LECP instrument steps through eight, 45 deg fullangle sectors, spending 192 sec in each sector, yielding a full scan through 360 deg every 25.6 min. The LECP scan plane is nearly parallel to RTplane of the heliospheric RTN coordinate system. The electron data are averaged over the seven active sectors S1S7; S8 is behind the sunshield and not included in the average.  Electron channels designated EB01 and EB02  Data have been corrected to remove background due to penetrating cosmic ray ions  Fluxes and uncertainties (one st. dev.) in units: electrons/cm^2ssrMeV  Data are 5point running averages of daily values  Values 9.900e+01 used for missing or nonphysical data  Negative year indicates filled data for the associated doy
This data set includes the Voyager spacecraft number (1 or 2), the datetime in decimal year (90.00000 is day 1 of 1990), the magnetic field strength F1 computed from highresolution magnitudes, the elevation and azimuth angles (degrees) in heliographic (RTN) coordinates, and the magnetic field strength F2 computed from hour averages of the components. The vector components of B can be computed from F2 and the two angles. Elevation angle is the latitude angle above or below the solar equatorial plane, and azimuth angle is in the direction orbital motion around the Sun from the projection of the Suntospacecraft axis into the solar equatorial plane. The Voyager MAG experiment and coordinates are further described in the following publication: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977...At the time of experiment proposal, it was expected that the required accuracy of the measurements would be 0.1 nT, determined by the combined noise of the sensors and the spacecraft field. The spacecraft magnetic field at the outboard magnetic field sensor, referred to as the primary unit, was expected to be 0.2 nT and highly variable, consistent with current estimates. Hence, the dual magnetometer design (Ness et al., 1971, 1973; Behannon et al. 1977). ..At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. ..References: ..Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977. ..Burlaga, L.F., Merged interaction regions and largescale magnetic field fluctuations during 1991  Voyager2 observations, J. Geophys. Res., 99 (A10), 1934119350, 1994. ..Burlaga, L.F., N.F. Ness, Y.M. Wang, and N.R. Sheeley Jr., Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002. ..Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., 76, 3564, 1971. ..Ness et al., 1973 At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. COORDINATE SYSTEMS: Interplanetary magnetic field studies make use of two important coordinate systems, the Inertial Heliographic (IHG) coordinate system and the Heliographic (HG) coordinate system. The IHG coordinate system is use to define the spacecraft's position. The IHG system is defined with its origin at the Sun. There are three orthogonal axes, X(IHG), Y(IHG), and Z(IHG). The Z(IHG) axis points northward along the Sun's spin axis. The X(IHG)  Y(IHG) plane lays in the solar equatorial plane. The intersection of the solar equatorial plane with the ecliptic plane defines a line, the longitude of the ascending node, which is taken to be the X(IHG) axis. The X(IHG) axis drifts slowly with time, approximately one degree per 72 years. Magnetic field orientation is defined in relation to the spacecraft. Drawing a line from the Sun's center (IHG origin) to the spacecraft defines the X axis of the HG coordinate system. The HG coordinate system is defined with its origin centered at the spacecraft. Three orthogonal axes are defined, X(HG), Y(HG), and Z(HG). The X(HG) axis points radially away from the Sun and the Y(HG) axis is parallel to the solar equatorial plane and therefore parallel to the X(IHG)Y(IHG) plane too. The Z(HG) axis is chosen to complete the orthonormal triad. An excellent reference guide with diagrams explaining the IHG and HG systems may be found in Space and Science Reviews, Volume 39 (1984), pages 255316, MHD Processes in the Outer Heliosphere, L. F. Burlaga.
Hardcoded V1/2 component uncertainty of 0.02 nT
Matrix 1 transforms three element vector from Inertial Heliographic to heliographic coordinates.
Matrix 2 transforms three element vector from Earth Mean ecliptic, Equinox of 1950 (EME 50) to Heliographic (HG) coordinates.
Matrix 3 transforms three element vector from payload coordinates to Heliographic coordinates.
This data set includes the Voyager spacecraft number (1 or 2), the datetime in decimal year (90.00000 is day 1 of 1990), the magnetic field strength F1 computed from highresolution magnitudes, the elevation and azimuth angles (degrees) in heliographic (RTN) coordinates, and the magnetic field strength F2 computed from hour averages of the components. The vector components of B can be computed from F2 and the two angles. Elevation angle is the latitude angle above or below the solar equatorial plane, and azimuth angle is in the direction orbital motion around the Sun from the projection of the Suntospacecraft axis into the solar equatorial plane. The Voyager MAG experiment and coordinates are further described in the following publication: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977...At the time of experiment proposal, it was expected that the required accuracy of the measurements would be 0.1 nT, determined by the combined noise of the sensors and the spacecraft field. The spacecraft magnetic field at the outboard magnetic field sensor, referred to as the primary unit, was expected to be 0.2 nT and highly variable, consistent with current estimates. Hence, the dual magnetometer design (Ness et al., 1971, 1973; Behannon et al. 1977). ..At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. ..References: ..Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977. ..Burlaga, L.F., Merged interaction regions and largescale magnetic field fluctuations during 1991  Voyager2 observations, J. Geophys. Res., 99 (A10), 1934119350, 1994. ..Burlaga, L.F., N.F. Ness, Y.M. Wang, and N.R. Sheeley Jr., Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002. ..Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., 76, 3564, 1971. ..Ness et al., 1973 At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. COORDINATE SYSTEMS: Interplanetary magnetic field studies make use of two important coordinate systems, the Inertial Heliographic (IHG) coordinate system and the Heliographic (HG) coordinate system. The IHG coordinate system is use to define the spacecraft's position. The IHG system is defined with its origin at the Sun. There are three orthogonal axes, X(IHG), Y(IHG), and Z(IHG). The Z(IHG) axis points northward along the Sun's spin axis. The X(IHG)  Y(IHG) plane lays in the solar equatorial plane. The intersection of the solar equatorial plane with the ecliptic plane defines a line, the longitude of the ascending node, which is taken to be the X(IHG) axis. The X(IHG) axis drifts slowly with time, approximately one degree per 72 years. Magnetic field orientation is defined in relation to the spacecraft. Drawing a line from the Sun's center (IHG origin) to the spacecraft defines the X axis of the HG coordinate system. The HG coordinate system is defined with its origin centered at the spacecraft. Three orthogonal axes are defined, X(HG), Y(HG), and Z(HG). The X(HG) axis points radially away from the Sun and the Y(HG) axis is parallel to the solar equatorial plane and therefore parallel to the X(IHG)Y(IHG) plane too. The Z(HG) axis is chosen to complete the orthonormal triad. An excellent reference guide with diagrams explaining the IHG and HG systems may be found in Space and Science Reviews, Volume 39 (1984), pages 255316, MHD Processes in the Outer Heliosphere, L. F. Burlaga.
Matrix 1 transforms three element vector from Inertial Heliographic to heliographic coordinates.
Matrix 2 transforms three element vector from Earth Mean ecliptic, Equinox of 1950 (EME 50) to Heliographic (HG) coordinates.
Matrix 3 transforms three element vector from payload coordinates to Heliographic coordinates.
This data set includes the Voyager spacecraft number (1 or 2), the datetime in decimal year (90.00000 is day 1 of 1990), the magnetic field strength F1 computed from highresolution magnitudes, the elevation and azimuth angles (degrees) in heliographic (RTN) coordinates, and the magnetic field strength F2 computed from hour averages of the components. The vector components of B can be computed from F2 and the two angles. Elevation angle is the latitude angle above or below the solar equatorial plane, and azimuth angle is in the direction orbital motion around the Sun from the projection of the Suntospacecraft axis into the solar equatorial plane. The Voyager MAG experiment and coordinates are further described in the following publication: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977...At the time of experiment proposal, it was expected that the required accuracy of the measurements would be 0.1 nT, determined by the combined noise of the sensors and the spacecraft field. The spacecraft magnetic field at the outboard magnetic field sensor, referred to as the primary unit, was expected to be 0.2 nT and highly variable, consistent with current estimates. Hence, the dual magnetometer design (Ness et al., 1971, 1973; Behannon et al. 1977). ..At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. ..References: ..Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977. ..Burlaga, L.F., Merged interaction regions and largescale magnetic field fluctuations during 1991  Voyager2 observations, J. Geophys. Res., 99 (A10), 1934119350, 1994. ..Burlaga, L.F., N.F. Ness, Y.M. Wang, and N.R. Sheeley Jr., Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002. ..Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., 76, 3564, 1971. ..Ness et al., 1973 At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. COORDINATE SYSTEMS: Interplanetary magnetic field studies make use of two important coordinate systems, the Inertial Heliographic (IHG) coordinate system and the Heliographic (HG) coordinate system. The IHG coordinate system is use to define the spacecraft's position. The IHG system is defined with its origin at the Sun. There are three orthogonal axes, X(IHG), Y(IHG), and Z(IHG). The Z(IHG) axis points northward along the Sun's spin axis. The X(IHG)  Y(IHG) plane lays in the solar equatorial plane. The intersection of the solar equatorial plane with the ecliptic plane defines a line, the longitude of the ascending node, which is taken to be the X(IHG) axis. The X(IHG) axis drifts slowly with time, approximately one degree per 72 years. Magnetic field orientation is defined in relation to the spacecraft. Drawing a line from the Sun's center (IHG origin) to the spacecraft defines the X axis of the HG coordinate system. The HG coordinate system is defined with its origin centered at the spacecraft. Three orthogonal axes are defined, X(HG), Y(HG), and Z(HG). The X(HG) axis points radially away from the Sun and the Y(HG) axis is parallel to the solar equatorial plane and therefore parallel to the X(IHG)Y(IHG) plane too. The Z(HG) axis is chosen to complete the orthonormal triad. An excellent reference guide with diagrams explaining the IHG and HG systems may be found in Space and Science Reviews, Volume 39 (1984), pages 255316, MHD Processes in the Outer Heliosphere, L. F. Burlaga. Support data calib_flag_on, calib_flag_MF and calib_flag_offset are added to file version 2. Variable calib_flag_on consists of points where bit 4 or 5 in variable magStatus equal 1. Variable calib_flag_MF represents observations where magnetometer was in cailbration mode. Variable calib_flag_offset represent delay between data points where magnetometer was in calibration mode and data points where magStatus variable indicated calibration periods.Due to specific shape of magnetometer data profile variable calibration_flag_MF may cover larger intervals than calibration_flag_on.
Matrix 1 transforms three element vector from Inertial Heliographic to heliographic coordinates.
Matrix 2 transforms three element vector from Earth Mean ecliptic, Equinox of 1950 (EME 50) to Heliographic (HG) coordinates.
Matrix 3 transforms three element vector from payload coordinates to Heliographic coordinates.
The main science objectives for the VOYAGER interplanetary mission are as follows:  investigate the structure of the solar wind magnetic fields and plasma in the inner and outer heliosphere;  conduct long term study of heliospheric evolution during different phases of the twentytwo year solar magnetic cycle and the elevenyear solar activity cycle;  study the long term solar modulation and determine the elemental and isotopic abundances of galactic cosmic ray particles in the heliosphere;  measure radial gradients, spectra, and nuclear abundances of the anomalous component of cosmic rays from acceleration at the solar wind termination shock;  investigate local particle acceleration in the interplanetary medium from solar flare shocks and corotating interaction regions;  study propagation of solar energetic particles in the heliosphere. The average magnetic field strength produced by the spacecraft at the location of the outboard magnetometer of the dual magnetometers system on V1 and V2 is about 0.1  0.2 nT, comparable to the most probable magnetic field strength in the inner heliosheath and significantly larger than the most probable magnetic field strength in the distant supersonic solar wind. The spacecraft magnetic field is a complex, timedependent signal that must be removed from the measured magnetic field signal in order to derive the ambient magnetic fields of the solar wind and heliosheath. Corrections must also be made for spurious magnetic signals and noise associated with the telemetry system, ground tracking systems, and other factors. Extracting the signal describing the solar wind and heliosheath from the many sources of uncertainty is a complex and partly subjective process that requires understanding of the instrument and judgment based on experience in dealing with the everchanging extraneous signals. We estimate that for the V1 MAG data the 1sigma the uncertainty the 48 sec averages for each of the components of the magnetic field BR, BT, and BN is typically +/ 0.02 nT; the uncertainty in magnitude F1 is typically +/ 0.03 nT. F1, BR, BT, and BN can differ from one another and they may vary with time, but there is no practical way to determine these uncertainties more precisely at present. References Daniel B. Berdichevsky, Voyager Mission, Detailed processing of weak magnetic fields; I  Constraints to the uncertainties of the calibrated magnetic field signal in the Voyager missions , 2009; https://vgrmag.gsfc.nasa.gov/BerdichevskyVOY_sensor_opu090518.pdf Behannon, K.W., M.H. Acu..a, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977. Burlaga, L.F., Merged interaction regions and largescale magnetic field fluctuations during 1991  Voyager2 observations, J. Geophys. Res., 99 (A10), 1934119350, 1994. Burlaga, L.F., N.F. Ness, Y.M. Wang, and N.R. Sheeley Jr., Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002. Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., , 76, 3564, 1971.
The main science objectives for the VOYAGER interplanetary mission are as follows:  investigate the structure of the solar wind magnetic fields and plasma in the inner and outer heliosphere;  conduct long term study of heliospheric evolution during different phases of the twentytwo year solar magnetic cycle and the elevenyear solar activity cycle;  study the long term solar modulation and determine the elemental and isotopic abundances of galactic cosmic ray particles in the heliosphere;  measure radial gradients, spectra, and nuclear abundances of the anomalous component of cosmic rays from acceleration at the solar wind termination shock;  investigate local particle acceleration in the interplanetary medium from solar flare shocks and corotating interaction regions;  study propagation of solar energetic particles in the heliosphere. This directory contains hourly averages of parameters for the interplanetary magnetic field, solar wind plasma and spacecraft trajectory coordinates VOYAGER1 data have been reprocessed to ensure a uniformity of content and coordinate systems relative to data from other deepspace missions:  All spacecraft trajectory data were transformed to a Heliographic Inertial (HGI) coordinate system.  calculation of the RTN Cartesian components of interplanetary magnetic field from the RTN spherical components: BR=B*cos(THETA)*cos(PHI) BT=B*cos(THETA)*sin(PHI) BN=B*sin(THETA) where THETA  spherical RTN latitude, PHI spherical RTN longtitude  calculation of RTN Spherical components of the solar wind velocity from RTN cartesian components: V = (Vr^2 + Vt^2 + Vn^2)^0.5 THETA=asin(Vn/V) PHI=atan(Vt/Vr) where THETA  spherical RTN latitude, PHI spherical RTN longtitude  calculation of given thermal speed Vth into temperature T (Kelvin): T=60.5*Vth^2 (Vth in km/s)  merging of trajectory coordinates, magnetic field data, and plasma data files into a single annual file VY1_YR.DAT, where YR is the year  Data gaps were filled with dummy numbers for the missing hours or entire days to make all files of equal length. The character \Ə\' is used to fill all fields for missing data according to their format, e.g. \' 9999.9\' for a field with the FORTRAN format F7.1. Note that format F7.1 below really means (1X,F6.1),etc.a Notes on Voyager 1 and 2 Magnetometer Data After 1989. At the time of experiment proposal, it was expected that the required accuracy of the measurements would be 0.1 nT, determined by the combined noise of the sensors and the spacecraft field. The spacecraft magnetic field at the outboard magnetic field sensor, referred to as the primary unit, was expected to be 0.2 nT and highly variable, consistent with current estimates. Hence, the dual magnetometer design (Ness et al., 1971; Behannon et al. 1977). At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is ..0.15 nT and ..0.05 nT, respectively. The use of roll calibrations lasting ..6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of ..3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 nT  0.05 nT. further informaion look at https://omniweb.gsfc.nasa.gov/coho/html/cw_data.html The Heliographic Inertial (HGI) coordinates are Suncentered and inertially fixed with respect to an Xaxis directed along the intersection line of the ecliptic and solar equatorial planes. The solar equator plane is inclined at 7.25 degrees from the ecliptic. This direction was towards ecliptic longitude of 74.36 degrees on 1 January 1900 at 1200 UT; because of precession of the celestial equator, this longitude increases by 1.4 degrees/century. The Z axis is directed perpendicular and northward from the solar equator, and the Yaxis completes the righthanded set. This system differs from the usual heliographic coordinates (e.g. Carrington longitudes) which are fixed in the frame of the rotating Sun. The RTN system is fixed at a spacecraft (or the planet). The R axis is directed radially away from the Sun, the T axis is the cross product of the solar rotation axis and the R axis, and the N axis is the cross product of R and T. At zero Heliographic Latitude when the spacecraft is in the solar equatorial plane the N and solar rotation axes are parallel. Hour averages of the interplanetary solar wind data from, and hourly heliocentric coordinates of, Voyager1/2 and other interplanetary spacecraft may be also be accessed and plotted online through the COHOWeb service http://cohoweb.gsfc.nasa.gov/ Acknowledgement: Use of these data in publications should be accompanied at minimum by acknowledgements of the National Space Science Data Center and the responsible Principal Investigator defined in the experiment documentation provided here. Citation of NSSDC's Coordinated Heliospheric Observations (COHO) data base would also be appreciated, so that other potential users will be made aware of this service. For questions about this data set, please contact: Dr. N. Papitashvili, natalia.e.papitashvili@nasa.gov, GSFCCode 672
Please visit Voyager CRS website https://voyager.gsfc.nasa.gov
No TEXT global attribute value.
These data are from a reanalysis of the Voyager Plasma Spectrometer (PLS) data at Jupiter by the PLS group at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado. Density, temperature, and flow velocity fits for total and individual ions were done using the Voyager Ion PLS Experiment Response (VIPER) code and error analysis as described at http://lasp.colorado.edu/home.mop/missions/voyager/viper/. Fits are determined from processing of the ion currents from the A, B, C, and D cups of the instrument.. As per the Fit Case variable, one of five different constraints were used in the VIPER fits for each 96sec time interval: (1) free variation of all parameters (mainly for the cold ion torus); (2) constraint of the ion abundances for the five major species (O+, O++, S+, S++, S+++) to standard composition as determined from Delamere et al. (2005); (3) fixed ion composition and flow speed; (4) cold blobs in the plasma sheet where resolved peaks can be fit with allowance for some variance in composition; (5) interpolation between composition of cold torus and standard abundances at 6 RJ from Delamere et al. (2005). Reference: Delamere, P. A., Bagenal, F., and Steffl, A. (2005), Radial Variations in the Io Plasma Torus During the Cassini Era, Journal of Geophysical Research Space Physics, 110(A12), A12223, doi: 10.1029/2005JA011251.
Spacecraft location in Right handed System III coordinate frame (RHSII) in absolute distances from Jupiter's center. RJ = 71,492 km.
RHSIII = Right Handed System III coordinates in Jovian magnetosphere
RHSII = RightHanded SystemIIII coordinates in Jovian magnetosphere
Methods of how the parameters being fit were handled by VIPER 1: Variation of all parameters (mostly the inner cold torus); 2: Constraining the ion abundances of the five main ion species (O+, O++, S+, S++, S+++) to the standard composition based on Delamere et al. [2005]; 3. Fixed ion composition plus fixed flow speed; 4. cold blobs in the plasma sheet where resolved peaks can be fit allowing some variations in composition; 5. Interpolation between the composition of the cold torus and the standard composition at 6 Jovian Radii from Delamere et al. [2005].
RHSIII = RightHanded System III coordinate system for spacecraft position in the Jovian magnetosphere.
RHSIII = RightHanded System III coordinate system for spacecraft position in the Jovian magnetosphere.
RHSIII = RightHanded System III coordinates of spacecraft position. Northward is in northern direction of the planetary spin axis.
1: These electron current spectra in the jovian magnetosphere are from the Plasma Spectrometer (PLS) instrument on Voyager 1 during March 1979 flyby of Jupiter. The instrument has four Faraday Cups A  D, the electron data come only from D. The data are specified in terms of current per cup in femtoamps (10^15 A) versus channel number and energy (eV). 2: This data set is for the PLS E1 mode covering electron energies of 10  140 eV in 16 energy channels. PLS samples only one mode of electron (E1, E2) or ion (L, M) spectra in each time intervals, so the E1 data are not continuous but consecutive with the other modes in time. 3: Reference: Bridge et al. (1977). The Plasma Experiment on the the 1977 Voyager Mission, Space Science Reviews, 21, 259287.
1 femtoamp = 10^15 amps
These electron current spectra in the jovian magnetosphere are from the Plasma Spectrometer (PLS) instrument on Voyager 1 during the March 1979 flyby of Jupiter. The instrument has four Faraday Cups A  D, the electron data come only from D. The data are specified in terms of current per cup in femtoamps (10^15 A) versus channel number and energy (eV). This data set is for the PLS E1 mode covering electron energies of 10  140 eV in 16 energy channels. PLS samples only one mode of electron (E1, E2) or ion (L, M) spectra in each time intervals, so the E1 data are not continuous but consecutive with the other modes in time. Reference: Bridge et al. (1977). The Plasma Experiment on the the 1977 Voyager Mission, Space Science Reviews, 21, 259287.
1 femtoamp = 10^15 amps
The files in this directory contain the Voyager fine resolution plasma data. The plasma parameters are obtained by finding the best fit of a convected isotropic Maxwellian distribution to the data. One sigma errors are typically less than 0.5% in the speed and VR, less than 5% for the density and thermal speed, and vary greatly for VT and VN. Sampling times range from 12 to 192 sec., with sampling generally more frequent early in the mission. The velocity components are given in the RTN coordinate system, where R is radially outward, T is in a plane parallel to the solar equatorial plane and positive in the direction of solar rotation, and N completes a righthanded system. (WARNING: V_t, and V_n parameters are often NOT reliable after 1989) Please consult with us, or at least send preprints, when you use this data to prevent grievous errors or misconceptions. (John Richardson, jdr@space.mit.edu)
These ion current spectra in the jovian magnetosphere are from the Plasma Spectrometer (PLS) instrument on Voyager 1 during the March 1979 flyby of Jupiter. The instrument has four Faraday Cups A  D, the electron data come only from D. The data are specified in terms of current per cup in femtoamps (10^15 A) versus channel number and energy (eV). This data set is for the PLS Lmode covering H+ ion energies of 10  5950 eV at low energy resolution in 16 logarithmic energy channels. PLS samples only one mode of electron (E1, E2) or ion (L, M) spectra in each time interval, so the Lmode data are not continuous but consecutive with the other modes in time. Reference: Bridge et al. (1977). The Plasma Experiment on the the 1977 Voyager Mission, Space Science Reviews, 21, 259287.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 20  11900 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 20  11900 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 20  11900 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 20  11900 eV.
These ion current spectra in the jovian magnetosphere are from the Plasma Spectrometer (PLS) instrument on Voyager 1 during the March 1979 flyby of Jupiter. The instrument has four Faraday Cups A  D, the electron data come only from D. The data are specified in terms of current per cup in femtoamps (10^15 A) versus channel number and energy (eV). This data set is for the PLS Mmode covering H+ ion energies of 10  5950 eV at high energy resolution in 128 logarithmic energy channels. PLS samples only one mode of electron (E1, E2) or ion (L, M) spectra in each time interval, so the Mmode data are not continuous but consecutive with the other modes in time. Reference: Bridge et al. (1977). The Plasma Experiment on the the 1977 Voyager Mission, Space Science Reviews, 21, 259287.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 10  5950 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 10  5950 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 10  5950 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 10  5950 eV.
This data set includes the Voyager spacecraft number (1 or 2), the datetime in decimal year (90.00000 is day 1 of 1990), the magnetic field strength F1 computed from highresolution magnitudes, the elevation and azimuth angles (degrees) in heliographic (RTN) coordinates, and the magnetic field strength F2 computed from hour averages of the components. The vector components of B can be computed from F2 and the two angles. Elevation angle is the latitude angle above or below the solar equatorial plane, and azimuth angle is in the direction orbital motion around the Sun from the projection of the Suntospacecraft axis into the solar equatorial plane. The Voyager MAG experiment and coordinates are further described in the following publication: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977...At the time of experiment proposal, it was expected that the required accuracy of the measurements would be 0.1 nT, determined by the combined noise of the sensors and the spacecraft field. The spacecraft magnetic field at the outboard magnetic field sensor, referred to as the primary unit, was expected to be 0.2 nT and highly variable, consistent with current estimates. Hence, the dual magnetometer design (Ness et al., 1971, 1973; Behannon et al. 1977). ..At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. ..References: ..Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977. ..Burlaga, L.F., Merged interaction regions and largescale magnetic field fluctuations during 1991  Voyager2 observations, J. Geophys. Res., 99 (A10), 1934119350, 1994. ..Burlaga, L.F., N.F. Ness, Y.M. Wang, and N.R. Sheeley Jr., Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002. ..Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., 76, 3564, 1971. ..Ness et al., 1973 At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. COORDINATE SYSTEMS: Interplanetary magnetic field studies make use of two important coordinate systems, the Inertial Heliographic (IHG) coordinate system and the Heliographic (HG) coordinate system. The IHG coordinate system is use to define the spacecraft's position. The IHG system is defined with its origin at the Sun. There are three orthogonal axes, X(IHG), Y(IHG), and Z(IHG). The Z(IHG) axis points northward along the Sun's spin axis. The X(IHG)  Y(IHG) plane lays in the solar equatorial plane. The intersection of the solar equatorial plane with the ecliptic plane defines a line, the longitude of the ascending node, which is taken to be the X(IHG) axis. The X(IHG) axis drifts slowly with time, approximately one degree per 72 years. Magnetic field orientation is defined in relation to the spacecraft. Drawing a line from the Sun's center (IHG origin) to the spacecraft defines the X axis of the HG coordinate system. The HG coordinate system is defined with its origin centered at the spacecraft. Three orthogonal axes are defined, X(HG), Y(HG), and Z(HG). The X(HG) axis points radially away from the Sun and the Y(HG) axis is parallel to the solar equatorial plane and therefore parallel to the X(IHG)Y(IHG) plane too. The Z(HG) axis is chosen to complete the orthonormal triad. An excellent reference guide with diagrams explaining the IHG and HG systems may be found in Space and Science Reviews, Volume 39 (1984), pages 255316, MHD Processes in the Outer Heliosphere, L. F. Burlaga.
Hardcoded V2/2 component uncertainty of 0.02 nT
Matrix 1 transforms three element vector from Inertial Heliographic to heliographic coordinates.
Matrix 2 transforms three element vector from Earth Mean ecliptic, Equinox of 1950 (EME 50) to Heliographic (HG) coordinates.
Matrix 3 transforms three element vector from payload coordinates to Heliographic coordinates.
This data set includes the Voyager spacecraft number (1 or 2), the datetime in decimal year (90.00000 is day 1 of 1990), the magnetic field strength F1 computed from highresolution magnitudes, the elevation and azimuth angles (degrees) in heliographic (RTN) coordinates, and the magnetic field strength F2 computed from hour averages of the components. The vector components of B can be computed from F2 and the two angles. Elevation angle is the latitude angle above or below the solar equatorial plane, and azimuth angle is in the direction orbital motion around the Sun from the projection of the Suntospacecraft axis into the solar equatorial plane. The Voyager MAG experiment and coordinates are further described in the following publication: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977...At the time of experiment proposal, it was expected that the required accuracy of the measurements would be 0.1 nT, determined by the combined noise of the sensors and the spacecraft field. The spacecraft magnetic field at the outboard magnetic field sensor, referred to as the primary unit, was expected to be 0.2 nT and highly variable, consistent with current estimates. Hence, the dual magnetometer design (Ness et al., 1971, 1973; Behannon et al. 1977). ..At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. ..References: ..Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977. ..Burlaga, L.F., Merged interaction regions and largescale magnetic field fluctuations during 1991  Voyager2 observations, J. Geophys. Res., 99 (A10), 1934119350, 1994. ..Burlaga, L.F., N.F. Ness, Y.M. Wang, and N.R. Sheeley Jr., Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002. ..Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., 76, 3564, 1971. ..Ness et al., 1973 At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. COORDINATE SYSTEMS: Interplanetary magnetic field studies make use of two important coordinate systems, the Inertial Heliographic (IHG) coordinate system and the Heliographic (HG) coordinate system. The IHG coordinate system is use to define the spacecraft's position. The IHG system is defined with its origin at the Sun. There are three orthogonal axes, X(IHG), Y(IHG), and Z(IHG). The Z(IHG) axis points northward along the Sun's spin axis. The X(IHG)  Y(IHG) plane lays in the solar equatorial plane. The intersection of the solar equatorial plane with the ecliptic plane defines a line, the longitude of the ascending node, which is taken to be the X(IHG) axis. The X(IHG) axis drifts slowly with time, approximately one degree per 72 years. Magnetic field orientation is defined in relation to the spacecraft. Drawing a line from the Sun's center (IHG origin) to the spacecraft defines the X axis of the HG coordinate system. The HG coordinate system is defined with its origin centered at the spacecraft. Three orthogonal axes are defined, X(HG), Y(HG), and Z(HG). The X(HG) axis points radially away from the Sun and the Y(HG) axis is parallel to the solar equatorial plane and therefore parallel to the X(IHG)Y(IHG) plane too. The Z(HG) axis is chosen to complete the orthonormal triad. An excellent reference guide with diagrams explaining the IHG and HG systems may be found in Space and Science Reviews, Volume 39 (1984), pages 255316, MHD Processes in the Outer Heliosphere, L. F. Burlaga.
Matrix 1 transforms three element vector from Inertial Heliographic to heliographic coordinates.
Matrix 2 transforms three element vector from Earth Mean ecliptic, Equinox of 1950 (EME 50) to Heliographic (HG) coordinates.
Matrix 3 transforms three element vector from payload coordinates to Heliographic coordinates.
This data set includes the Voyager spacecraft number (1 or 2), the datetime in decimal year (90.00000 is day 1 of 1990), the magnetic field strength F1 computed from highresolution magnitudes, the elevation and azimuth angles (degrees) in heliographic (RTN) coordinates, and the magnetic field strength F2 computed from hour averages of the components. The vector components of B can be computed from F2 and the two angles. Elevation angle is the latitude angle above or below the solar equatorial plane, and azimuth angle is in the direction orbital motion around the Sun from the projection of the Suntospacecraft axis into the solar equatorial plane. The Voyager MAG experiment and coordinates are further described in the following publication: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977...At the time of experiment proposal, it was expected that the required accuracy of the measurements would be 0.1 nT, determined by the combined noise of the sensors and the spacecraft field. The spacecraft magnetic field at the outboard magnetic field sensor, referred to as the primary unit, was expected to be 0.2 nT and highly variable, consistent with current estimates. Hence, the dual magnetometer design (Ness et al., 1971, 1973; Behannon et al. 1977). ..At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. ..References: ..Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977. ..Burlaga, L.F., Merged interaction regions and largescale magnetic field fluctuations during 1991  Voyager2 observations, J. Geophys. Res., 99 (A10), 1934119350, 1994. ..Burlaga, L.F., N.F. Ness, Y.M. Wang, and N.R. Sheeley Jr., Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002. ..Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., 76, 3564, 1971. ..Ness et al., 1973 At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. [1994] and in Appendix A of Burlaga et al. [2002]. COORDINATE SYSTEMS: Interplanetary magnetic field studies make use of two important coordinate systems, the Inertial Heliographic (IHG) coordinate system and the Heliographic (HG) coordinate system. The IHG coordinate system is use to define the spacecraft's position. The IHG system is defined with its origin at the Sun. There are three orthogonal axes, X(IHG), Y(IHG), and Z(IHG). The Z(IHG) axis points northward along the Sun's spin axis. The X(IHG)  Y(IHG) plane lays in the solar equatorial plane. The intersection of the solar equatorial plane with the ecliptic plane defines a line, the longitude of the ascending node, which is taken to be the X(IHG) axis. The X(IHG) axis drifts slowly with time, approximately one degree per 72 years. Magnetic field orientation is defined in relation to the spacecraft. Drawing a line from the Sun's center (IHG origin) to the spacecraft defines the X axis of the HG coordinate system. The HG coordinate system is defined with its origin centered at the spacecraft. Three orthogonal axes are defined, X(HG), Y(HG), and Z(HG). The X(HG) axis points radially away from the Sun and the Y(HG) axis is parallel to the solar equatorial plane and therefore parallel to the X(IHG)Y(IHG) plane too. The Z(HG) axis is chosen to complete the orthonormal triad. An excellent reference guide with diagrams explaining the IHG and HG systems may be found in Space and Science Reviews, Volume 39 (1984), pages 255316, MHD Processes in the Outer Heliosphere, L. F. Burlaga. Support data calib_flag_on, calib_flag_MF and calib_flag_offset are added to file version 2. Variable calib_flag_on consists of points where bit 4 or 5 in variable magStatus equal 1. Variable calib_flag_MF represents observations where magnetometer was in cailbration mode. Variable calib_flag_offset represent delay between data points where magnetometer was in calibration mode and data points where magStatus variable indicated calibration periods.Due to specific shape of magnetometer data profile variable calibration_flag_MF may cover larger intervals than calibration_flag_on.
Matrix 1 transforms three element vector from Inertial Heliographic to heliographic coordinates.
Matrix 2 transforms three element vector from Earth Mean ecliptic, Equinox of 1950 (EME 50) to Heliographic (HG) coordinates.
Matrix 3 transforms three element vector from payload coordinates to Heliographic coordinates.
The main science objectives for the VOYAGER interplanetary mission are as follows:  investigate the structure of the solar wind magnetic fields and plasma in the inner and outer heliosphere;  conduct long term study of heliospheric evolution during different phases of the twentytwo year solar magnetic cycle and the elevenyear solar activity cycle;  study the long term solar modulation and determine the elemental and isotopic abundances of galactic cosmic ray particles in the heliosphere;  measure radial gradients, spectra, and nuclear abundances of the anomalous component of cosmic rays from acceleration at the solar wind termination shock;  investigate local particle acceleration in the interplanetary medium from solar flare shocks and corotating interaction regions;  study propagation of solar energetic particles in the heliosphere. The average magnetic field strength produced by the spacecraft at the location of the outboard magnetometer of the dual magnetometers system on V1 and V2 is about 0.1  0.2 nT, comparable to the most probable magnetic field strength in the inner heliosheath and significantly larger than the most probable magnetic field strength in the distant supersonic solar wind. The spacecraft magnetic field is a complex, timedependent signal that must be removed from the measured magnetic field signal in order to derive the ambient magnetic fields of the solar wind and heliosheath. Corrections must also be made for spurious magnetic signals and noise associated with the telemetry system, ground tracking systems, and other factors. Extracting the signal describing the solar wind and heliosheath from the many sources of uncertainty is a complex and partly subjective process that requires understanding of the instrument and judgment based on experience in dealing with the everchanging extraneous signals. We estimate that for the V1 MAG data the 1sigma the uncertainty the 48 sec averages for each of the components of the magnetic field BR, BT, and BN is typically +/ 0.02 nT; the uncertainty in magnitude F1 is typically +/ 0.03 nT. F1, BR, BT, and BN can differ from one another and they may vary with time, but there is no practical way to determine these uncertainties more precisely at present. References Daniel B. Berdichevsky, Voyager Mission, Detailed processing of weak magnetic fields; I  Constraints to the uncertainties of the calibrated magnetic field signal in the Voyager missions , 2009; https://vgrmag.gsfc.nasa.gov/BerdichevskyVOY_sensor_opu090518.pdf Behannon, K.W., M.H. Acu..a, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, MagneticField Experiment for Voyager1 and Voyager2, Space Science Reviews, 21 (3), 235257, 1977. Burlaga, L.F., Merged interaction regions and largescale magnetic field fluctuations during 1991  Voyager2 observations, J. Geophys. Res., 99 (A10), 1934119350, 1994. Burlaga, L.F., N.F. Ness, Y.M. Wang, and N.R. Sheeley Jr., Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002. Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., , 76, 3564, 1971.
The main science objectives for the VOYAGER interplanetary mission are as follows:  investigate the structure of the solar wind magnetic fields and plasma in the inner and outer heliosphere;  conduct long term study of heliospheric evolution during different phases of the twentytwo year solar magnetic cycle and the elevenyear solar activity cycle;  study the long term solar modulation and determine the elemental and isotopic abundances of galactic cosmic ray particles in the heliosphere;  measure radial gradients, spectra, and nuclear abundances of the anomalous component of cosmic rays from acceleration at the solar wind termination shock;  investigate local particle acceleration in the interplanetary medium from solar flare shocks and corotating interaction regions;  study propagation of solar energetic particles in the heliosphere. This directory contains hourly averages of parameters for the interplanetary magnetic field, solar wind plasma and spacecraft trajectory coordinates VOYAGER1 data have been reprocessed to ensure a uniformity of content and coordinate systems relative to data from other deepspace missions:  All spacecraft trajectory data were transformed to a Heliographic Inertial (HGI) coordinate system.  calculation of the RTN Cartesian components of interplanetary magnetic field from the RTN spherical components: BR=B*cos(THETA)*cos(PHI) BT=B*cos(THETA)*sin(PHI) BN=B*sin(THETA) where THETA  spherical RTN latitude, PHI spherical RTN longtitude  calculation of RTN Spherical components of the solar wind velocity from RTN cartesian components: V = (Vr^2 + Vt^2 + Vn^2)^0.5 THETA=asin(Vn/V) PHI=atan(Vt/Vr) where THETA  spherical RTN latitude, PHI spherical RTN longtitude  calculation of given thermal speed Vth into temperature T (Kelvin): T=60.5*Vth^2 (Vth in km/s)  merging of trajectory coordinates, magnetic field data, and plasma data files into a single annual file VY1_YR.DAT, where YR is the year  Data gaps were filled with dummy numbers for the missing hours or entire days to make all files of equal length. The character \Ə\' is used to fill all fields for missing data according to their format, e.g. \' 9999.9\' for a field with the FORTRAN format F7.1. Note that format F7.1 below really means (1X,F6.1),etc.a Notes on Voyager 1 and 2 Magnetometer Data After 1989. At the time of experiment proposal, it was expected that the required accuracy of the measurements would be 0.1 nT, determined by the combined noise of the sensors and the spacecraft field. The spacecraft magnetic field at the outboard magnetic field sensor, referred to as the primary unit, was expected to be 0.2 nT and highly variable, consistent with current estimates. Hence, the dual magnetometer design (Ness et al., 1971; Behannon et al. 1977). At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is ..0.15 nT and ..0.05 nT, respectively. The use of roll calibrations lasting ..6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis (which is nearly parallel to the radius vector to the Sun) at intervals of ..3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 nT  0.05 nT. further informaion look at https://omniweb.gsfc.nasa.gov/coho/html/cw_data.html The Heliographic Inertial (HGI) coordinates are Suncentered and inertially fixed with respect to an Xaxis directed along the intersection line of the ecliptic and solar equatorial planes. The solar equator plane is inclined at 7.25 degrees from the ecliptic. This direction was towards ecliptic longitude of 74.36 degrees on 1 January 1900 at 1200 UT; because of precession of the celestial equator, this longitude increases by 1.4 degrees/century. The Z axis is directed perpendicular and northward from the solar equator, and the Yaxis completes the righthanded set. This system differs from the usual heliographic coordinates (e.g. Carrington longitudes) which are fixed in the frame of the rotating Sun. The RTN system is fixed at a spacecraft (or the planet). The R axis is directed radially away from the Sun, the T axis is the cross product of the solar rotation axis and the R axis, and the N axis is the cross product of R and T. At zero Heliographic Latitude when the spacecraft is in the solar equatorial plane the N and solar rotation axes are parallel. Hour averages of the interplanetary solar wind data from, and hourly heliocentric coordinates of, Voyager1/2 and other interplanetary spacecraft may be also be accessed and plotted online through the COHOWeb service http://cohoweb.gsfc.nasa.gov/ Acknowledgement: Use of these data in publications should be accompanied at minimum by acknowledgements of the National Space Science Data Center and the responsible Principal Investigator defined in the experiment documentation provided here. Citation of NSSDC's Coordinated Heliospheric Observations (COHO) data base would also be appreciated, so that other potential users will be made aware of this service. For questions about this data set, please contact: Dr. N. Papitashvili, natalia.e.papitashvili@nasa.gov, GSFCCode 672
No TEXT global attribute value.
These data are from a reanalysis of the Voyager Plasma Spectrometer (PLS) data at Jupiter by the PLS group at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado. Density, temperature, and flow velocity fits for total and individual ions were done using the Voyager Ion PLS Experiment Response (VIPER) code and error analysis as described at http://lasp.colorado.edu/home.mop/missions/voyager/viper/. Fits are determined from processing of the ion currents from the A, B, C, and D cups of the instrument.. As per the Fit Case variable, one of five different constraints were used in the VIPER fits for each 96sec time interval: (1) free variation of all parameters (mainly for the cold ion torus); (2) constraint of the ion abundances for the five major species (O+, O++, S+, S++, S+++) to standard composition as determined from Delamere et al. (2005); (3) fixed ion composition and flow speed; (4) cold blobs in the plasma sheet where resolved peaks can be fit with allowance for some variance in composition; (5) interpolation between composition of cold torus and standard abundances at 6 RJ from Delamere et al. (2005). Reference: Delamere, P. A., Bagenal, F., and Steffl, A. (2005), Radial Variations in the Io Plasma Torus During the Cassini Era, Journal of Geophysical Research Space Physics, 110(A12), A12223, doi: 10.1029/2005JA011251.
Spacecraft location in Right handed System III coordinate frame (RHSII) in absolute distances from Jupiter's center. RJ = 71,492 km.
RHSIII = Right Handed System III coordinates in Jovian magnetosphere
RHSII = RightHanded SystemIIII coordinates in Jovian magnetosphere
Methods of how the parameters being fit were handled by VIPER 1: Variation of all parameters (mostly the inner cold torus); 2: Constraining the ion abundances of the five main ion species (O+, O++, S+, S++, S+++) to the standard composition based on Delamere et al. [2005]; 3. Fixed ion composition plus fixed flow speed; 4. cold blobs in the plasma sheet where resolved peaks can be fit allowing some variations in composition; 5. Interpolation between the composition of the cold torus and the standard composition at 6 Jovian Radii from Delamere et al. [2005].
RHSIII = RightHanded System III coordinate system for spacecraft position in the Jovian magnetosphere.
RHSIII = RightHanded System III coordinate system for spacecraft position in the Jovian magnetosphere.
RHSIII = RightHanded System III coordinates of spacecraft position. Northward is in northern direction of the planetary spin axis.
These electron current spectra in the jovian magnetosphere are from the Plasma Spectrometer (PLS) instrument on Voyager 1 during the March 1979 flyby of Jupiter. The instrument has four Faraday Cups A  D, the electron data come only from D. The data are specified in terms of current per cup in femtoamps (10^15 A) versus channel number and energy (eV). This data set is for the PLS E1 mode covering electron energies of 10  140 eV in 16 energy channels. PLS samples only one mode of electron (E1, E2) or ion (L, M) spectra in each time intervals, so the E1 data are not continuous but consecutive with the other modes in time. Reference: Bridge et al. (1977). The Plasma Experiment on the the 1977 Voyager Mission, Space Science Reviews, 21, 259287.
1 femtoamp = 10^15 amps
These electron current spectra in the jovian magnetosphere are from the Plasma Spectrometer (PLS) instrument on Voyager 1 during the March 1979 flyby of Jupiter. The instrument has four Faraday Cups A  D, the electron data come only from D. The data are specified in terms of current per cup in femtoamps (10^15 A) versus channel number and energy (eV). This data set is for the PLS E1 mode covering electron energies of 10  140 eV in 16 energy channels. PLS samples only one mode of electron (E1, E2) or ion (L, M) spectra in each time intervals, so the E1 data are not continuous but consecutive with the other modes in time. Reference: Bridge et al. (1977). The Plasma Experiment on the the 1977 Voyager Mission, Space Science Reviews, 21, 259287.
1 femtoamp = 10^15 amps
The files in this directory contain the Voyager fine resolution plasma data. The plasma parameters are obtained by finding the best fit of a convected isotropic Maxwellian distribution to the data. One sigma errors are typically less than 0.5% in the speed and VR, less than 5% for the density and thermal speed, and vary greatly for VT and VN. Sampling times range from 12 to 192 sec., with sampling generally more frequent early in the mission. The velocity components are given in the RTN coordinate system, where R is radially outward, T is in a plane parallel to the solar equatorial plane and positive in the direction of solar rotation, and N completes a righthanded system. (WARNING: V_t, and V_n parameters are often NOT reliable after 1989) Please consult with us, or at least send preprints, when you use this data to prevent grievous errors or misconceptions. (John Richardson, jdr@space.mit.edu)
The files in this directory contain the Voyager fine resolution plasma data. The plasma parameters are obtained by finding the best fit of a convected isotropic Maxwellian distribution to the data. One sigma errors are typically less than 0.5% in the speed and VR, less than 5% for the density and thermal speed, and vary greatly for VT and VN. Sampling times range from 12 to 192 sec., with sampling generally more frequent early in the mission. The velocity components are given in the RTN coordinate system, where R is radially outward, T is in a plane parallel to the solar equatorial plane and positive in the direction of solar rotation, and N completes a righthanded system. (WARNING: V_t, and V_n parameters are often NOT reliable after 1989) Please consult with us, or at least send preprints, when you use this data to prevent grievous errors or misconceptions. (John Richardson, jdr@space.mit.edu)
a measure of how good the fit to the data is, lower is better
These ion current spectra in the jovian magnetosphere are from the Plasma Spectrometer (PLS) instrument on Voyager 2 during the July 1979 flyby of Jupiter. The instrument has four Faraday Cups A  D, the electron data come only from D. The data are specified in terms of current per cup in femtoamps (10^15 A) versus channel number and energy (eV). This data set is for the PLS Lmode covering H+ ion energies of 10  5950 eV at low energy resolution in 16 logarithmic energy channels. PLS samples only one mode of electron (E1, E2) or ion (L, M) spectra in each time interval, so the Lmode data are not continuous but consecutive with the other modes in time. Reference: Bridge et al. (1977). The Plasma Experiment on the the 1977 Voyager Mission, Space Science Reviews, 21, 259287.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 20  11900 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 20  11900 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 20  11900 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 20  11900 eV.
These ion current spectra in the jovian magnetosphere are from the Plasma Spectrometer (PLS) instrument on Voyager 2 during the July 1979 flyby of Jupiter. The instrument has four Faraday Cups A  D, the electron data come only from D. The data are specified in terms of current per cup in femtoamps (10^15 A) versus channel number and energy (eV). This data set is for the PLS Mmode covering H+ ion energies of 10  5950 eV at high energy resolution in 128 logarithmic energy channels. PLS samples only one mode of electron (E1, E2) or ion (L, M) spectra in each time interval, so the Mmode data are not continuous but consecutive with the other modes in time. Reference: Bridge et al. (1977). The Plasma Experiment on the the 1977 Voyager Mission, Space Science Reviews, 21, 259287.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 10  5950 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 10  5950 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 10  5950 eV.
1 femtoamp = 10^15 amps. The equivalent energy coverage for He++ is 10  5950 eV.