Mirror instability: From quasi-linear diffusion to coherent structures
Résumé
A model for the nonlinear dynamics of mirror modes near the instability threshold is presented. By matching the quasi-linear theory for the space-averaged distribution function with a reductive perturbative description of the mirror modes, the model reproduces the early-time flattening of the distribution function and the development of magnetic humps from an initial noise, in agreement with Vlasov-Maxwell numerical simulations. It suggests a possible mechanism at the origin of the mirror structures observed in planetary magnetosheaths and in the solar wind.
Domaines
Planète et Univers [physics]
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