Weak turbulence theory of the non-linear evolution of the ion ring distribution
Abstract
The nonlinear evolution of an ion ring instability in a low-beta magnetospheric plasma is considered. The evolution of the two-dimensional ring distribution is essentially quasilinear. Ignoring nonlinear processes the time-scale for the quasilinear evolution is the same as for the linear instability 1/t_ql gamma_l. However, when nonlinear processes become important, a new time scale becomes relevant to the wave saturation mechanism. Induced nonlinear scattering of the lower-hybrid waves by plasma electrons is the dominant nonlinearity relevant for plasmas in the inner magnetosphere and typically occurs on the timescale 1/t_ql w(M/m)W/nT, where W is the wave energy density, nT is the thermal energy density of the background plasma, and M/m is the ion to electron mass ratio, which has the consequence that the wave amplitude saturates at a low level, and the timescale for quasilinear relaxation is extended by orders of magnitude.
Keywords
Cite
@article{arxiv.1103.3715,
title = {Weak turbulence theory of the non-linear evolution of the ion ring distribution},
author = {M. Mithaiwala and L. Rudakov1 and G. Ganguli and C. Crabtree},
journal= {arXiv preprint arXiv:1103.3715},
year = {2015}
}