Particle-In-Cell Simulations of a Nonlinear Transverse Electromagnetic Wave in a Pulsar Wind Termination Shock

Abstract

A 2.5-dimensional particle-in-cell code is used to investigate the propagation of a large-amplitude, superluminal, nearly transverse electromagnetic (TEM) wave in a relativistically streaming electron-positron plasma with and without a shock. In the freestreaming, unshocked case, the analytic TEM dispersion relation is verified, and the streaming is shown to stabilize the wave against parametric instabilities. In the confined, shocked case, the wave induces strong, coherent particle oscillations, heats the plasma, and modifies the shock density profile via ponderomotive effects. The wave decays over $\gtrsim 10^2$ skin depths; the decay length scale depends primarily on the ratio between the wave frequency and the effective plasma frequency, and on the wave amplitude. The results are applied to the termination shock of the Crab pulsar wind, where the decay length-scale (at least 0.05") might be comparable to the thickness of filamentary, variable substructure observed in the optical and X-ray wisps and knots.

arXiv comment10 pages, 4 figures. Accepted for publication in ApJ (2005)

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Cited by in corpus (8)

• Pulsar Wind Nebulae as Cosmic Pevatrons: A Current Sheet's Tale
• The Role of Superluminal Electromagnetic Waves in Pulsar Wind Termination Shocks
• Electric Current Circuits in Astrophysics
• Superluminal waves in pulsar winds
• Propagation and stability of superluminal waves in pulsar winds
• Radiation from Comoving Poynting Flux Acceleration
• Electromagnetic spin down of a transient accreting millisecond pulsar during quiescence
• The stability of strong waves and its implications for pulsar wind shocks