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Advanced Composition Explorer Level 2 SWEPAM 64-sec Solar Wind Ion Data, ASCII


Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)

Time span: 1998-01-23 to 2000-07-01


This data collection contains Level 2 data files in ASCII format from the Solar Wind Electron, Proton and Alpha Monitor (SWEPAM) experiment on the Advanced Composition Explorer (ACE) spacecraft. Each file contains solar wind ion data from one Bartel interval of 27 days at a time resolution for individual records of 64 seconds. 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). 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 data set has been converted to ASCII from the original version (NSSDC ID No. 97-045A-07A) provided by the ACE Science Center in NCSA Hierarchical Data Format (HDF).

This collection is available on-line at:

Alternate Names

  • SWEPAM Level-2 64-s Ion Data,ASC


  • Space Physics: Heliospheric Studies


  • 97-045A-07E

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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