HR: 10:43h
AN: SH22A-02 INVITED     [Abstracts]
TI: What Have we Learnt From Three Solar Cycles of Gamma-ray Observations?
AU: * Trottet, G
EM: gerard.trottet@obspm.fr
AF: LESIA, Observatoire de Paris, 5, Place J. Janssen, Meudon, 92190, France
AB: Gamma-ray observations of solar flares are the most direct and quantitative diagnostics of high-energy electrons and ions accelerated at the Sun. The theory of solar gamma-rays has been established in the late 1960's and pioneer observations of nuclear gamma-ray lines have been obtained in the early 1970's by OSO-7. Since 1980 observations of gamma-ray line and continuum emissions have been continuously performed by instruments on board various satellites. The aim of this presentation is to outline what has been learnt on the characteristics of energetic electrons and ions accelerated and interacting at the Sun during flares, e.g.: energy spectra of electrons and ions, chemical composition of accelerated ions, characteristic time-scales of acceleration/transport, location of electron and ion interaction regions and angular distribution of interacting ions. Although this large amount of observations has allowed us to make substantial progress in our understanding of particle acceleration during solar flares, some open questions remain like.: what are the low- and high-energy cut-offs of accelerated ions and how do they vary from flare to flare; do flares of all sizes accelerate ions?. We briefly discuss how future measurements of low energy neutrons and sub-millimeter/far-infrared emissions will contribute to answer the above questions.
DE: 7514 Energetic particles (2114)
DE: 7519 Flares
DE: 7534 Radio emissions
DE: 7536 Solar activity cycle (2162)
DE: 7554 X-rays, gamma rays, and neutrinos
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Joint Assembly