Advanced Composition Explorer (ACE) Solar Wind Electron, Proton, and Alpha Monitor (SWEPAM) Level 2 Data

The electrostatic analyzers measure the energy per charge of each particle by bending their flight paths through the system. The fields-of-view are swept across all solar wind directions by the rotation of the spacecraft. WEPAM level 2 data is organized into 27-day time periods (Bartels Rotations - roughly one solar rotation period).

For each Bartels Rotation, the level 2 data contains time averages of solar wind parameters over the following time periods: - 64 seconds (ion data only) - 128 seconds (electron data only) - hourly - (all data) daily - (all data) 27 days (1 Bartels rotation) (all data) SWEPAM level 2 data consists of the following data items: - Ion data o Proton Density (np in cm -3) o Radial Component of the Proton Temperature (TP,rr in o Kelvin) o Ratio of Alpha Density to proton Density (nHe/nP) o Proton Speed (VP in km/s) o Proton Velocity Vector in GSE coordinates (in km/s) o Proton Velocity Vector in RTN coordinates (in km/s) o Proton Velocity Vector in GSM coordinates (in km/s) - Electron data o Electron Temperature (in o Kelvin) (not yet available) See: srl.caltech.edu/ACE/ASC/level2/swepam_l2desc.html