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SPRG Seminars - Archive
October 16, 2007:
Novel components of solar flare hard X-ray emission
Alec MacKinnon, University of Glasgow, UK
We discuss the possible contribution to solar flare hard X-rays from two radiation mechanisms: neutron decay inner bremsstrahlung and inverse Compton scattering of optical photons. Neither of these is likely to rival electron-ion bremsstrahlung in producing the bulk of the total flare X-radiation. Their diagnostic implications are quite distinct, however, and it may be possible to discriminate them in spatially resolved observations (particularly from RHESSI). After recalling the physical operation of these two mechanisms we discuss their possible diagnostic use. Inverse Compton radiation might in particular account for some isolated, coronal sources. If diagnosed it would tell us about flare electrons in the MeV energy range. Inner bremsstrahlung from flare energetic neutrons would have a large angular extent and might be best diagnosed in flares on the far side of the Sun. It would provide a new insight into flare ion acceleration.