2006/11/06 by Eduard P. Kontar, John C. Brown · 2 citations
Physics and Astronomy · #Electron #Electron spectroscopy #History and Developments in Astronomy #Ionosphere and magnetosphere dynamics #Solar and Space Plasma Dynamics #Solar flare #Solar physics #Spacecraft #Spectral line #Spectroscopy #Stereoscopy #astro-ph
paper · pdf · doi:10.1086/510586
published as Astrophys.J.653:L149-L152,2006 · 7 pages, 3 figures, accepted to Astrophysical Journal Letters
arxiv created 2006/11/06 · openalex publication_date 2006/12/04 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Hard X-ray (HXR) spectroscopy is the most direct method of diagnosing energetic electrons in solar flares. Here we present a technique that allows us to use a single HXR spectrum to determine an effectively stereoscopic electron energy distribution. Considering the Sun's surface to act as a "Compton mirror" allows us to look at emitting electrons also from behind the source, providing vital information on downward-propagating particles. Using this technique we determine simultaneously the electron spectra of downward- and upward-directed electrons for two solar flares observed by the Ramaty High Energy Solar Spectroscopic Imager ( RHESSI) . The results reveal surprisingly near-isotropic electron distributions, which contrast strongly with the expectations from the standard model that invokes strong downward beaming, including a collisional thick-target model.