Kappa-Maxwellian Electrons and Bi-Maxwellian Protons in a Two-fluid Model for Fast Solar Wind

Abstract

Modeling fast solar wind based on the kinetic theory is an important task for scientists. In this paper, we present a two-fluid model for fast solar wind with anisotropic Kappa-Maxwellian electrons and Bi-Maxwellian protons. In the simulation, the energy exchange between the plasma particles and low-frequency Alfvén waves is considered. A set of eleven coupled equations is derived by applying the zeroth-to fourth-order moments of the Vlasov equation and the modified electromagnetic Maxwell equations. A characteristic of the Kappa distribution (indicated by κ index) is explicit in the equation for the parallel component of the electron heat flux (parallel to the ambient magnetic field line) and differs from the equation derived for the proton heat flux due to the different nature of the distributions. Within the large κ index, the equations for the two-fluid model tend to the equations obtained by the Maxwellian distribution.Using an iterated Crank-Nicolson method, the coupled equations are numerically solved for the fast solar wind conditions. We show that at (0.3 -1) AU from the Sun, the electron density, components of temperature, and components of heat flux follow the power-law behavior. We also showed that near the Earth, the flow speed (electron or proton) increases with decreasing κ. We concluded that applying the small κ index (the non-MaxwellianCorresponding author: Hossein Safari safari@znu.ac.ir Taran, Safari, Daei distribution), the extraordinary nature of the solar atmosphere, with its temperature of several million kelvin temperature for electrons, has been captured.

A Quasi-linear Diffusion Model for Resonant Wave–Particle Instability in Homogeneous Plasma

“…For the numerical evaluation of our theoretical description, we develop a mathematical approach based on the Crank-Nicolson scheme (for numerical details, see Appendix A) that solves the full quasi-linear diffusion equation. Because of its reliable stability, the Crank-Nicolson scheme has been used previously to solve diffusion equations in a variety of fields (Khazanov et al 2002;Albert 2004;Brügmann et al 2004;Yang et al 2009;Klein & Chandran 2016;Taran et al 2019). However, most standard Crank-Nicolson schemes ignore the off-diagonal terms in the diffusion equation.…”

Complex Network for Solar Protons and Correlations With Flares

“…A solar storm is a flux of SEPs which is carried by the solar wind and can be detrimental to astronauts' health or damage the electrical devices in space or even on the Earth (Feynman & Gabriel, 2000; Jiggens et al., 2014). Simply, a geomagnetic storm can be defined as a major disturbance in the Earth's magnetic field that may be the result of sudden and drastic changes in the solar wind (Taran et al., 2019, and references therein), leading to changes in the current, plasma, and magnetic fields of the magnetosphere. It is accepted that the geomagnetic storms on the Earth may affect radio communication and cause hardware damage on satellites and the global positioning system (GPS).…”

A Quasi-Linear Diffusion Model for Resonant Wave-Particle Instability in Homogeneous Plasma

“…For the numerical evaluation of our theoretical description, we develop a mathematical approach based on the Crank-Nicolson scheme (for numerical details, see Appendix A) that solves the full quasi-linear diffusion equation. Because of its reliable stability, the Crank-Nicolson scheme has been used previously to solve diffusion equations in a variety of fields (Khazanov et al 2002;Albert 2004;Brügmann et al 2004;Yang et al 2009;Klein & Chandran 2016;Taran et al 2019). However, most standard Crank-Nicolson schemes neglect the off-diagonal terms in the diffusion equation.…”