Collisionless ion-electron energy exchange in magnetized shocks.

Zhang, Y; Heuer, P V; Wen, H; Davies, J R; Ren, C; Schaeffer, D B; Blackman, E G; Zhang, J et al. · Phys Rev E · 2026

basic_science · Level V

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Abstract

Energy partition between ions and electrons in collisionless shocks has been a long-standing unsolved fundamental physical question. We show that kinetic simulations of moderate Alfvénic Mach number, magnetized, collisionless shocks reveal rapid, faster-than-Coulomb, energy exchange between ions and electrons when the plasma is sufficiently magnetized. Using kinetic and multifluid models with counter-streaming ions, we identify resonances between electron whistler and ion magnetohydrodynamic waves that account for this rapid energy exchange.