Solar electron beam transport in the inner heliosphere

QB Astronomy;QC Physics

Reid, Hamish Andrew Sinclair ; Kontar, Eduard

University:University of Glasgow

Department:School of Physics and Astronomy

关键词: Energetic electrons, sun, Langmuir wave, radio emission, solar flare, x-ray emission, heliosphere;   

Others  :  http://theses.gla.ac.uk/2370/1/2011ReidPhd.pdf

来源: University of Glasgow

【 摘 要 】

Impulsive solar electron beams have an attractive diagnostic potential for poorly understood particle acceleration processes in solar flares.Solar flare accelerated electron beams propagating away from the Sun can interact with the turbulent interplanetary media, producing Langmuir waves and type III radio emission.In this thesis, we simulate electron beam propagation from the Sun to the Earth in the weak turbulent regime taking into account the self-consistent generation of Langmuir waves.We show that an injected single power-law spectrum will be detected at 1 AU as a broken power-law due to wave-particle interaction in the inhomogeneous plasma.We further extend these results by investigating the Langmuir wave interaction with background electron density fluctuations from low frequency MHD turbulence.We find a direct correlation between the spectra of the double power-law below the break energy and the turbulent intensity of the background plasma.Solar flares are believed to accelerate both upward and downward propagating electron beams which can radiate emission at radio and X-ray wavelengths correspondingly. The correlation between X-ray and radio emissions in a well observed solar flare allowed us detailed study of the electron acceleration region properties. We used the Nancay Radioheliograph, Phoenix-2 and RHESSI to infer the type III position, type III starting frequency and spectral index of the HXR emission respectively. Using these datasets and numerical simulations of the electron beam transport in the corona plasma, we were able to infer not only the location (the height in the corona), but to estimate the spatial length of the electron acceleration site.