Workshop on Laboratory Astrophysics

Radiation-driven diffusive transport of fast electrons in solar flares

20 Jun 2023, 14:55

25m

Conference Room (1st floor)

Talk Contributed talks

Speaker

Vladimir Tikhonchuk (Centre Lasers Intenses et Applications, Université de Bordeaux-CNRS-CEA, 33405 Talence, France; Extreme Light Infrastructure ERIC, ELI Beamlines Facility, 25241 Dolní Brežany, Czech Republic)

Description

Fast electron scattering on plasma ions due to stimulated Bremsstrahlung is investigated and modelled. Comparison with Coulomb scattering, at non-relativistic energies, suggests that stimulated Bremsstrahlung scattering can be dominant and observable in radiation-driven, low density, large scale astrophysical plasmas. The conditions are met in the flaring solar corona. The effect of the solar microwave radiation on fast-electron scattering is evaluated from a parameterized flaring corona model. We find that stimulated Bremsstrahlung greatly enhances the fast-electron scattering frequency in the flare magnetic loop, leading the transport of deka-keV electrons to occur in the diffusion regime, characterized by significant precipitation rates. This prediction is consistent with the interpretation of the above-loop-top hard X-ray and microwave emissions from the X3.1 flare of August 24, 2002. Our analysis indicates that stimulated Bremsstrahlung may play an essential role in the dynamics of fast electrons trapped in solar flare loops.