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Advanced Composition Explorer Level 2 SWEPAM 1-Day Solar Wind Plasma, HDF


Availability: At NSSDC, Ready for Electronic Access

Time span: 1998-01-23 to 2004-05-05


This data collection contains Level 2 data files in NCSA Hierarchical Data Format (HDF) from the Solar Wind Electron, Proton and Alpha Monitor (SWEPAM) experiment on the Advanced Composition Explorer (ACE) spacecraft. Each file contains all solar wind data from one Bartel interval of 27 days with individual records averaged over one day of data. Each record contains solar wind proton density (cm-3), radial component of the proton temperature (Kelvin), alpha/proton density ratio, and proton speed (km/s). Electron temperature will later be included but is not yet available. The proton velocity vector components (km/s) are given in Geocentric Solar Ecliptic (GSE), Heliographic (RTN), and Geocentric Solar Magnetospheric (GSM) coordinates. The ACE spacecraft position is included in GSE and GSM coordinates. A data value of -9999.9 indicates bad or missing data for the given time period. Release notes on Level 2 processing are given in the text file swepam_release_notes.txt.

This collection is available on-line at:

Alternate Names

  • SWEPAM Level-2 1day SW Plasma,HDF


  • Space Physics: Heliospheric Studies


  • 97-045A-07C

Additional Information



Questions and comments about this data collection can be directed to: Dr. John F. Cooper



NameRoleOriginal AffiliationE-mail
Dr. Andrew J. DavisGeneral ContactCalifornia Institute of
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