Quasilinear Analysis of Electromagnetic Electron Cyclotron and Electron Firehose Instabilities in Homogeneous and in Inhomogeneous Solar Wind Plasmas

A macroscopic quasilinear approach along with standard methodology of kinetic fluid modeling adopted to investigate the details of excitation, damping and saturation of electron temperature anisotropy-driven electromagnetic electron cyclotron (EMEC) and electron firehose (EFH) instabilities in homogeneous and in inhomogeneous (density and magnetic field profiles) solar wind plasmas. We constructed a closing set of self-consistent quasilinear equations constituting the particle kinetic, wave energy density and linearized Vlasov equations with the aid of single electrons component and halo component bi-Maxwellian model distributions except that electrons temperatures may evolve in time t. In literature, the threshold conditions of microinstabilities are obtained from linear theory, hybrid simulations, or directly from observational fits. While, in our present technique, the solutions of kinetic equations inherently contain the so-called anisotropy-beta inverse relationship such that the empirical fitting is automatically reproduced at the end of each quasilinear calculation. Nevertheless, the empirical formula, which is built from consideration of linear analysis, cannot predict the timescale of instability saturation or the asymptotic wave energy density. Such an approach amounts to global-kinetic solar wind modeling suggested in the literature, and to reproduce the so-called ``Bale'' diagram.