Publication Date:
2023-07-25
Description:
It is shown that the ratio of the proton convective gyroradius r_{Ep} to the width of the shock ramp D controls the thermalisation process of ions in quasi-perpendicular shocks. When r_{Ep}/D〉1 the solar wind beam energy is rapidly converted to gyration (thermal) energy by an universal, stochastic, transit-time thermalisation (TTT) mechanism that does not require any collisions, waves, or instabilities. The stochastic TTT of ions on magnetic field gradients is followed by the stochastic wave energisation (SWE) on electric field gradients. Ions heated by the TTT and SWE processes are subject to additional ballistic surfing acceleration (BSA) by the convection field in the shock front. These three fundamental ion energisation mechanisms are studied with test-particle simulations in a realistic shock model and are shown to be consistent with Magnetospheric Multiscale (MMS) measurements in the Earth's bow shock.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
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