Numerical Construction of Magnetosphere with Relativistic Two-fluid Plasma Flows

TL;DR

This paper develops a numerical model to simulate relativistic two-fluid plasma flows in pulsar magnetospheres, capturing electromagnetic fields and plasma dynamics without assuming ideal MHD conditions.

Contribution

It introduces a self-consistent numerical approach for modeling relativistic plasma flows in pulsar magnetospheres without pair creation or radiation loss assumptions.

Findings

Demonstrates plasma acceleration and deceleration due to electric fields.

Successfully models weak magnetic fields and highly relativistic flows.

Highlights the importance of boundary conditions for realistic pulsar magnetosphere simulations.

Abstract

We present a numerical model in which a cold pair plasma is ejected with relativistic speed through a polar cap region and flows almost radially outside the light cylinder. Stationary axisymmetric structures of electromagnetic fields and plasma flows are self-consistently calculated. In our model, motions of positively and negatively charged particles are assumed to be determined by electromagnetic forces and inertial terms, without pair creation and annihilation or radiation loss. The global electromagnetic fields are calculated by the Maxwell's equations for the plasma density and velocity, without using ideal MHD condition. Numerical result demonstrates the acceleration and deceleration of plasma due to parallel component of the electric fields. Numerical model is successfully constructed for weak magnetic fields or highly relativistic fluid velocity, i.e, kinetic energy dominated outflow. It is found that appropriate choices of boundary conditions and plasma injection model at the polar cap should be explored in order to extend present method to more realistic pulsar magnetosphere, in which the Poynting flux is dominated.