Oscillatory disintegration of a trans-Alfvenic shock: A magnetohydrodynamic simulation

Nonlinear evolution of a trans-Alfvenic shock wave (TASW), at which the flow velocity passes over the Alfven velocity, is computed in a magnetohydrodynamic approximation. The analytical theory suggests that an infinitesimal perturbation of a TASW results in its disintegration, i.e., finite variation of the flow, or transformation into some other unsteady configuration. In the present paper, this result is confirmed by numerical simulations. It is shown that the disintegration time is close to its minimum value equal to the shock thickness divided by a relative velocity of the emerging secondary structures. The secondary TASW that appears after the disintegration is again unstable with respect to disintegration. When the perturbation has a cyclic nature, the TASW undergoes oscillatory disintegration, during which it repeatedly transforms into another TASW. This process manifests itself as a train of shock and rarefaction waves, which consecutively emerge at one edge of the train and merge at the other edge.Comment: REVTEX, 8 pages, 13 PostScript figures, uses epsfig.st

Collective oscillations in a plasma

International Series of Monographs in Natural Philosophy: Collective Oscillations in a Plasma, Volume 7 presents specific topics within the general field of radio waves propagation. This book contains five chapters that address the theory of linear oscillations in a plasma, the spectra of the eigen oscillations, and the mechanism of high-frequency heating. The opening chapters deal with the self-consistent fields; development of initial perturbation; dispersion permittivity tensor of a plasma in a magnetic field; effect of thermal motion of particles on low-frequency resonances; excitation o