Compton Getting Correction for STEREO SEPT
Abstract
STEREO was launched on October 25, 2006. The Solar Electron and Proton Telescope (SEPT) consists of two dual double-ended magnetic/foil particle telescopes: SEPT-E in the ecliptic plane and SEPT-NS perpendicular to the ecliptic plane. This setup provides four looking directions for each spacecraft: one looking to the Sun along the nominal Parker spiral 45 degrees west from the spacecraft-Sun line, another looking along the Parker spiral but in the anti-solar direction, and two additional apertures looking North and South in a plane perpendicular to the ecliptic. The nominal energy range is 70 keV to 6.5 MeV for ions, mainly protons and helium, and 30-400 keV for electrons. Since the velocity of several 10 keV protons and helium is of the same magnitude as the solar wind speed, an isotropic pitch angle distribution in the solar wind frame is expected to become anisotropic in the spacecraft frame. This is the so-called Compton Getting effect. This effect is negligible for electrons in the observed energy range due to their high speeds. Based on the work of Ipavich (1974) we developed a method to correct the SEPT ion data accordingly. As SEPT cannot resolve elements, the method is also designed to account for helium contribution. We will show that the data can be transformed successfully and apply the method to a number of selected CIR events.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMSM11B1616G
- Keywords:
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- 2104 Cosmic rays;
- 2114 Energetic particles (7514);
- 2194 Instruments and techniques