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arXiv · 1907.10294

Physics of relativistic collisionless shocks: III The suprathermal particles

Martin Lemoine·Guy Pelletier·Arno Vanthieghem·Laurent Gremillet
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Abstract

In this third paper of a series, we discuss the physics of the population of accelerated particles in the precursor of an unmagnetized, relativistic collisionless pair shock. In particular, we provide a theoretical estimate of their scattering length $l_{scatt}(p)$ in the self-generated electromagnetic turbulence, as well as an estimate of their distribution function. We obtain $l_{scatt}(p) \simeq (\gamma_p /\epsilon_B)(p/\gamma_{\infty} mc)^2 (c/\omega_p)$, with p the particle momentum in the rest frame of the shock front, $\epsilon_B$ the strength parameter of the microturbulence, $\gamma_p$ the Lorentz factor of the background plasma relative to the shock front and $\gamma_{\infty}$ its asymptotic value outside the precursor. We compare this scattering length to large-scale PIC simulations and find good agreement for the various dependencies.

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Martin Lemoine, Guy Pelletier, Arno Vanthieghem, Laurent Gremillet. 2019-07-24. Physics of relativistic collisionless shocks: III The suprathermal particles. https://doi.org/10.1103/physreve.100.033210

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