Open AccessBeam-plasma instability, the features of HXR spectra and polarization in solar flares
Author(s) -
Yu. E. Charikov,
I. V. Kudryavtsev
Publication year - 2020
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1697/1/012014
Subject(s) - physics , plasma , electron , spectral line , polarization (electrochemistry) , atomic physics , radiation , flare , solar flare , linear polarization , secondary electrons , instability , cathode ray , distribution function , optics , astrophysics , chemistry , laser , quantum mechanics , astronomy , mechanics
A one-dimensional quasi-linear beam relaxation leads to the formation of a plateau-like electron distribution function. Of greatest practical interest is the case when the initial velocity of the beam v 0 greatly exceeds the thermal velocity of the plasma electrons V T , and the initial velocity spread in the beam ∼Δv 0 is small compared with v 0 . These conditions are usually met for solar flares. The article deals with the features of the energy spectra and polarization of hard x-ray radiation (HXR) in the energy range of 20 -150 keV generated by electrons with a plateau-like electron distribution function. Calculations in the framework of a thick target take into account not only the energy losses of electrons interacting with plasma particles, but also changes in their angular distribution. It is shown that the break down energy of the electron spectrum leads to changes in HXR spectra, as well as the degree of linear polarization. There is a characteristic softening of the spectrum near the break-down energy. HXR polarization increases with quanta energy and can reach tens of percent.