Solar Wind Measurements During Intense CMEs from ACE/SWEPAM

We provide solar wind measurements for several intense Coronal Mass Ejections collected by the Solar Wind Electron Proton Alpha Monitor (SWEPAM) instrument (McComas et al. 1998) on the Advanced Composition Explorer (ACE). During these events, the normal SWEPAM solar wind speed track mode with a 64 second cadence did not work owing to the presence of penetrating radiation and rapid changes in the solar wind speed. These data are not archived in the standard archives available at the NASA Coordinated Data Analysis Web (CDAWeb) or ACE Science Center.

However, the search mode which measures the full energy range did work. These search mode observations have about a 33 minute resolution and the energy range coverage spans from 17,900 eV/q with 12% energy resolution. Owing to the presence of penetrating radiation and rapid changes in the solar wind, the analysis for these search mode observations is different. These search mode solar parameters are determined by fitting Maxwellians to the distribution functions after removing any penetrating background radiation. This analysis technique is described in Skoug et al. (2004).

References:

Skoug, R. M., Gosling, J. T., Steinberg, J. T., McComas, D. J., Smith, C. W., Ness, N. F., et al. (2004). Extremely high speed solar wind: 29-30 October 2003. Journal of Geophysical Research: Space Physics, 109(A), 9102. https://doi.org/10.1029/2004JA010494
McComas, D. J., Bame, S. J., Barker, P., Feldman, W. C., Phillips, J. L., Riley, P., & Griffee, J. W. (1998). Solar Wind Electron Proton Alpha Monitor (SWEPAM) for the Advanced Composition Explorer. Space Science Reviews, 86(1), 563-612. "https://doi.org/10.1023/A:1005040232597

Please contact Dr. R. Skoug ( ) with any questions regarding the use of these data.

Last Updated: May 2025

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