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.

arXiv commentto be published in Physical Review D

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Cited by in corpus (8)

• Relativistic Fluid Dynamics: Physics for Many Different Scales
• Relativistic fluid dynamics: physics for many different scales
• Generalized Relativistic Magnetohydrodynamic Equations for Pair and Electron-Ion Plasmas
• Generalized General Relativistic MHD Equations and Distinctive Plasma Dynamics around Rotating Black Holes
• Resistive relativistic magnetohydrodynamics from a charged multi-fluids perspective
• Linear Wave Propagation for Resistive Relativistic Magnetohydrodynamics
• Generalized general-relativistic magnetohydrodynamic equations for plasmas of active galactic nuclei in the era of the Event Horizon Telescope
• Group velocity and causality in standard relativistic resistive magnetohydrodynamics