Particle acceleration in Alfv\'enic turbulence with a strong guide field

Daniel Humphrey; Stanislav Boldyrev; Vadim Roytershteyn

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arXiv · 2608.25985

Particle acceleration in Alfv\'enic turbulence with a strong guide field

Daniel Humphrey·Stanislav Boldyrev·Vadim Roytershteyn

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Abstract

Magnetically dominated Alfv\'enic turbulence creates an effective environment for particle acceleration. However, when a strong mean field is present, traditional mechanisms like mirror and curvature acceleration become inefficient at explaining non-thermal particle energy distributions. Based on numerical and phenomenological study, we propose that in such turbulence, particles are accelerated in charge-starved current sheets, corresponding to current velocities approaching the speed of light. The distributions of the electric currents, plasma density, fluctuations of electric charge, as well as the energy distributions of accelerated particles, approximately follow log-normal statistics. Non-thermal particle distributions thus arise from particle acceleration in these charge-starved current sheets rather than from conventional Fermi-type particle acceleration by turbulent eddies.

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Daniel Humphrey, Stanislav Boldyrev, Vadim Roytershteyn. 2026-08-26. Particle acceleration in Alfv\'enic turbulence with a strong guide field. https://arxiv.org/abs/2608.25985

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