Propagation of Electromagnetic Waves in Resistive Pair Plasma and Causal Relativistic Magnetohydrodynamics

Abstract

We investigate the propagation of electromagnetic waves in resistive pair plasmas using a onefluid theory derived from the relativistic two-fluid equations. When the resistivity normalized by the electron/positron inertia variable exceeds a critical value, the dispersion relation for electromagnetic waves shows that the group velocity is larger than the light speed in vacuum. However, in such a case, it also is found that the plasma parameter is less than unity: that is, the electron-positron pair medium no longer can be treated as plasma. Thus the simple two-fluid approximation is invalid. This confirms that superluminal propagation of electromagnetic wave is forbidden in a plasma -- a conclusion consistent with the relativistic principle of causality. As an alternative, we propose a new set of equations for ``causal relativistic magnetohydrodynamics", which both have non-zero resistivity and yet are consistent with the causality principle.

to be published in Physical Review D

References in corpus (4)

• Multi-dimensional Numerical Scheme for Resistive Relativistic MHD
• "Meissner effect" and Blandford-Znajek mechanism in conductive black hole magnetospheres
• Two-dimensional MHD simulations of relativistic magnetic reconnection
• Energy Extraction from a Rotating Black Hole by Magnetic Reconnection in Ergosphere

Cited by in corpus (2)

• Generalized Relativistic Magnetohydrodynamic Equations for Pair and Electron-Ion Plasmas
• Generalized general-relativistic magnetohydrodynamic equations for plasmas of active galactic nuclei in the era of the Event Horizon Telescope