Alfvén waves in shear flows revisited

Abstract

We revisit our earlier study of the evolution of an initial propagating Alfvén wave in a magnetic-field-aligned flow with a cross-field velocity shear. Our goal is to show how the Alfvén wave drives up plasma density fluctuations which might be observed and serve as a signature of the presence of Alfvén waves in regions such as the solar corona which are inaccessible to direct observations. Here, we introduce a new initial condition which takes into account the initial distortion of the streamlines by the Alfvén wave, and we present new analytical results for the driven waves. We find that the density fluctuations of a properly placed linearly polarized Alfvén wave in a shear flow are much smaller than we originally estimated. © 2012 The American Astronomical Society. All rights reserved.