Physical Mechanism of Wave‐Particle Resonances in an Inhomogeneous Magnetic Field. I. Linear Theory

Phys. Fluids 24, 1650 (1981)https://ireap.umd.edu/10.1063/1.8635881981Journal ArticlePlasma, Accelerator, and Nuclear Physics

A physical description is given of the wave‐particle resonance which can occur when particles undergoing a ∇ B drift are in phase with a wave propagating across the magnetic field (i.e., ω ∼ k⋅V_∇ B, where V_∇ B is the ∇ B drift velocity). Specifically, the physics of the energy exchange mechanism is discussed and a general equation for the wave damping/growth rate is derived based upon physical arguments. The theory is applied to the lower‐hybrid‐drift instability and collisionless trapped electron instability.