Ion and relativistic electron acceleration and transport, and gamma ray production, in solar flares.

摘要

Observations made with the Gamma-Ray Spectrometer on Solar Maximum Mission have yielded a wealth of data on gamma-ray production in solar flares. In this dissertation, we develop acceleration and transport models for ions and relativistic electrons, and employ both Monte Carlo simulations and the Fokker-Planck formalism to calculate gamma-ray emission and compare with available data.;We consider the transport of relativistic electrons in a realistic solar flare magnetic loop model, consisting of a semicircular coronal segment and two convergent flux tubes which extend into the photosphere. In a simplified thick-target interaction region, we also consider pion production by a variety of proton distributions. We calculate the spectra of gamma rays resulting from the decay of neutral pions and the interactions of the secondary electrons and positrons. We find that pion radiation can account for the preferential detection of flares with ;We then address steady-state particle acceleration. For stochastic Fermi acceleration, we relate the acceleration efficiency and the spectral parameter to physical quantities, discuss the implication of assuming an energy-independent escape time, and present relativistically-correct spectra. We then develop a gyroresonant acceleration model in which turbulent Alfven and whistler waves are able to account for the simultaneous acceleration of protons and relativistic electrons.;Lastly, we develop a time-dependent gyroresonant acceleration model for ions which employs the realistic solar flare magnetic loop mentioned above and in which the damping of the turbulence is taken into account. We can account for both the energy spectra of protons and the time profiles of the nuclear-deexcitation line emission. We have also identified an efficient preacceleration mechanism for protons in nonlinear Landau damping.