Self-organization of magnetoacoustic waves in a thermally unstable environment

Abstract

The nonlinear evolution of magnetoacoustic waves in a nonadiabatic plasma is investigated analytically. The effect of plasma activity due to linear and quadratic heating and radiative cooling on propagating magnetoacoustic waves in a uniform plasma is considered. A nonlinear evolution equation is derived and stationary solutions are looked for the various combination of signs of the linear and quadratic heating-cooling terms, which determine the thermal activity of the plasma. It is shown that self-organizing magnetoacoustic waves (autowaves) exist in an active plasma. These wave have amplitudes that are independent from the initial conditions and function of plasma properties only. Their potential diagnostic purposes are discussed. Furthermore, magnetoacoustic autosolitary waves are shown to exist. They have been modeled using a novel perturbative technique, which allows to determine their propagation speed and shape.