Self-distortion of a whistler pulse in a plasma


  • V. K. Tripathi


Following the technique used by Akhmanov et al. to solve the nonlinear wave equation, we have investigated the propagation of temporally and spatially gaussian whistler pulses in a plasma. In the linear case the temporal width of the pulse is enhanced (due to dispersion) at a distance R ˜ τ2v3g/(∂2ω/∂k2) whereas its size is enhanced (due to diffraction) over a length Rd ∼ 2kr20/(1 + ϵ+zz); τ, r0, k, vg, ϵ+, and ϵzz are the initial time width, size, wave vector, group velocity, and the components of the dielectric tensor of the plasma. In the case of a high-power whistler, the ponderomotive nonlinearity causes self-focusing (for all values of ω/ωc) of the whistler and results in severe distortion of the pulse shape.