Electron heating in quasi‐perpendicular shocks: A Monte Carlo Simulation

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Abstract
To study the problem of electron heating in quasi‐perpendicular shocks, under the combined effects of “reversible” motion, in the shock electric potential and magnetic field, and wave‐particle interactions we have derived a diffusion equation, in the drift (adiabatic) approximation and we have solved it, using a Monte Carlo method. The results show that most of the observations can be explained within this framework. Our simulation has also definitively shown that the electron parallel temperature is determined by the dc electromagnetic field and not by any wave particle induced heating. Wave‐particle interactions are effective in smoothing out the large gradients in phase space produced by the “reversible” motion of the electrons, thus producing a “cooling” of the electrons. Some constraints on the wave‐particle interaction process may be obtained from a detailed comparison between the simulation and observations. In particular, it appears that the adiabatic approximation must be violated in order to explain the observed evolution of the perpendicular temperature.