2025/10/09 by Peng, Jingyu, He, Jiansen
#FOS: Physical sciences #Plasma Physics (physics.plasm-ph) #Space Physics (physics.space-ph)
paper · doi:10.48550/arxiv.2510.07875
Finite-amplitude low-frequency Alfvén waves are commonly found in plasma environments, such as space plasmas, and play a crucial role in ion heating. The nonlinear interaction between oblique Alfvén wave spectra and ions has been studied. As the number of wave modes increases, ions are more likely to exhibit chaotic motion and experience stochastic heating. The stochastic heating threshold in the parameter space can be characterized by a single parameter, the effective relative curvature radius Peff.. The results show excellent agreement with the chaotic regions identified through test particle simulations. The anisotropic characteristics of stochastic heating are explained using a uniform solid angle distribution model. The stochastic heating rate Q=T is calculated, and its relationship with wave conditions is expressed as Q/(Ωi mi vA2) = H(α) v3 Bw2 ω1, where α is propagating angle, Ωi is the gyrofrequency, mi is the ion mass, vA is the Alfvén speed, v is the dimensionless speed, Bw is the dimensionless wave amplitude, and ω1 is the lowest dimensionless wave frequency.