Effects Of Langmuir Waves On Flare-accelerated Electrons In The Inhomogeneous Coronal Plasma
Abstract
Solar flares accelerate beams of electrons, the number and energy of which may be estimated from the hard X-rays (HXR) they emit. The standard collisional thick target model assumes the emitting electrons are modified only by collisions. However, the electron beam produces Langmuir waves as it propagates through the inhomogeneous solar corona. The interaction between these Langmuir waves and density fluctuations, in the limit of fluctuations with spatial scale much larger than the Langmuir wavelength, can be described by a diffusion equation. We evaluate the diffusion coefficient for various spectra of density fluctuations, considering both those due to waves with a defined dispersion relation, and those with arbitrary frequency and wavenumber spectra. Simulations for the case of a 1-dimensional electron beam generating Langmuir waves which then diffuse, showed an acceleration effect on the electrons, increasing the number at high energies in the time-integrated distribution. The magnitude and form of the diffusion coefficient may therefore be important in the interpretation of HXR observations of non-thermal electrons, as the increased number of electrons at high energies could lead to an overestimate of the total number and energy of the originally accelerated electrons.
- Publication:
-
American Astronomical Society Meeting Abstracts #220
- Pub Date:
- May 2012
- Bibcode:
- 2012AAS...22052101R