In this article we demonstrated results of the numerical modeling of autowave pulses sequence generation processin thermally unstable plasma medium for the cases of perpendicular and parallel exterior magnetic field

During previous years, the conditions for the negative second (bulk) viscosity existence were found in a large number of nonequilibrium media. The media with negative viscosity possess a number of new properties including acoustical activity. In the present paper, we investigate the nonlinear stage of acoustical perturbation evolution in acoustically active nonequilibrium media using three models: the vibrationally excited gas with the exponential model of relaxation, the chemical active two component mixture with a nonequilibrium reaction and media with the general heat-loss function. The general nonlinear acoustical equation describing stationary density profiles behind the shock wave front in these media is obtained and solved. Its low- and high- frequency limits correspond to the Kuramoto-Sivashinsky equation and the Burgers equation with a source, respectively. Stationary structures of general equation, the conditions of their establishment and all their parameters are found analytically and numerically. In acoustically active media, it is predicted the existence of the stationary solitary pulse. Unstable weak shock waves disintegrate into the sequence of solitary pulses. Their amplitude, form, and speed are rigidly defined by the nonequilibrium degree and do not depend on the initial weak perturbation amplitude. For weak nonequilibrium degree, this solitary pulse is described analytically.

Пермский национальный исследовательский политехнический университет

В статье работе рассмотрена задача об эволюции нелинейных акустических структур в средах, где значимую роль играет наличие магнитного поля.

В работе получены решения дифференциальных уравнений, описывающих стационарные профили ударноволновых структур в неравновесном релаксирующем газе с внешним источником энергии. Исследованы одномерные и двумерные (плоская и цилиндрическая) ударноволновые структуры.