Flux Ropes, Turbulence, and Collisionless Perpendicular Shock Waves

An outstanding question that has received surprisingly little attention has been how turbulence interacts with collisionless shock waves. Turbulence in the supersonic solar wind is described frequently as a superposition of a majority 2D and a minority slab component. We formulate a collisional perpendicular shock-turbulence transmission problem in a way that enables investigation of the interaction and transmission of quasi-perpendicular fluctuations such as magnetic flux ropes/islands and vortices as well as entropy and acoustic modes in the large plasma beta regime. We find that the downstream spectral amplitude is typically increased significantly, and that the upstream spectral index of the inertial range, and the general spectral shape, is unchanged for the downstream magnetic variance, kinetic energy, and density variance. A comparison of the theoretically predicted downstream magnetic variance, kinetic energy, and destiny variance spectra with those observed by Wind, Ulysses, and Voyager 2 shows excellent agreement. We present a more extensive statistical comparison of the theory with several hundred shocks in the solar wind finding surprisingly good agreement. We conclude with some recent simulations of the interaction of current sheets and turbulence with perpendicular shocks.