New regimes of stochastic wave growth: Theory, simulation, and comparison with data

Abstract

Stochastic growth theory (SGT) of bursty waves is generalized and it is shown that the theory of “elementary bursts,” previously used to describe bursty emission in certain solar plasmas, is a limiting case of the generalized theory. New regimes of strong and weak stochastic growth are found, the boundaries separating the regimes are elucidated, and a reduced-parameter quasilinear model is used to constrain growth dynamics. The analytic results are then compared with simulations using the reduced-parameter model. Upon re-analysis of data from situations previously studied using SGT or other theories, including spacecraft data and results of particle-in-cell and quasilinear simulations, good agreement is found with the predictions of the generalized theory. In particular, data collapse of stochastic wave statistics is accomplished onto a universal curve with no free parameters.