Open AccessPlasma Emission versus Electron Cyclotron Maser Emission due to Power-law Energetic Electrons in Differently Magnetized Coronal Plasmas
Author(s) -
Xiaowei Zhou,
D. J. Wu,
L. Chen
Publication year - 2022
Publication title -
astrophysical journal/the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.3847/1538-4357/ac5aae
Subject(s) - physics , atomic physics , electron , plasma , maser , electromagnetic radiation , cyclotron , waves in plasmas , plasma oscillation , excited state , computational physics , astrophysics , nuclear physics , optics
By using self-consistent 2.5-dimensional particle-in-cell simulations, we study the excitation efficiency of electromagnetic waves by power-law energetic electrons with an anisotropic pitch-angle velocity distribution, which can simultaneously trigger the Langmuir and electron cyclotron maser instabilities, in differently magnetized coronal plasmas. It is found that the (transverse) electromagnetic waves can be excited much more efficiently in the case of strongly magnetized plasmas with ω ce > ω pe than that of weakly magnetized plasmas with ω ce < ω pe , where ω ce and ω pe are the electron cyclotron frequency and the electron plasma frequency, respectively. In particular, in a weakly magnetized plasma the electromagnetic wave is hardly excited effectively via the nonlinear coupling of Langmuir waves; although the Langmuir waves can be generated by the power-law energetic electrons, implying that the so-called plasma emission does not effectively work. These results can be helpful for us to better understand the physical mechanism of solar radio bursts.