Thresholdless stochastic particle heating by a single wave

Abstract

Stochastic heating is a well-known mechanism through which magnetized particles may be energized by low-frequency electromagnetic waves. In its simplest version, under spatially homogeneous conditions, it is known to be operative only above a threshold in the normalized wave amplitude, which may be a demanding requisite in actual scenarios, severely restricting its range of applicability. In this work we show, by numerical simulations supported by inspection of the particle Hamiltonian, that allowing for even a very weak spatial inhomogeneity completely removes the threshold, trading the requirement upon the wave amplitude with a requisite upon the duration of the interaction between wave and particle. The thresholdless chaotic mechanism considered here is likely to be applicable to other inhomogeneous systems.

V2. Some minor mistakes corrected

References in corpus (4)

• Nature of stochastic ion heating in the solar wind: testing the dependence on plasma beta and turbulence amplitude
• The Enhancement of Proton Stochastic Heating in the near-Sun Solar Wind
• Stochastic ion and electron heating on drift instabilities at the bow shock
• Radial evolution of stochastic heating in low-$\beta$ solar wind

Cited by in corpus (2)

• Charged particle energization by low-amplitude electrostatic waves at cyclotron harmonics
• Geometric investigation of chaos unfolding in Hamiltonian systems