An overdamped Langevin approach to parallel diffusion and energy dissipation in the presence of low-frequency circularly polarized electromagnetic waves

Brownian motion of charged particles in the presence of low-frequency, circularly polarized electromagnetic waves is discussed. By using the wave rest frame, the Langevin system including low-frequency waves can be treated as a periodic system with a constant external force. In an overdamped limit, parallel diffusion is formulated by the Brownian motion whose diffusion coefficient includes wave amplitude. The nonequilibrium work by low-frequency waves satisfies a nonequilibrium relation corresponding to the fluctuation–dissipation relation with the effective temperature defined by wave amplitude.