Instability of Whistler‐Dominated Laminar Shocks

A large‐amplitude whistler is taken as a model of a collisionless laminar shock and shown to be unstable for perturbations propagating at angles to the whistler. The parameter space of instability is delineated and growth lengths as short as several whistler wavelengths are shown to exist for certain classes of perturbations. The deterioration of a laminar shock structure to a turbulent one, therefore, seems highly probable.