Wave drag in moving plasmas: Recent developments and prospects

Wave propagation in a medium differs depending on whether this medium is at rest or moving with respect to an observer. Motion can notably lead to modifications of the wave trajectory, of its polarization, or of its transverse structure. Although these effects are well documented in isotropic dielectrics, they remain largely unexplored and unaccounted for in plasmas, despite the fact that simple models suggest they could in fact be large under certain conditions, as well as recent experimental observations. Here, we first review existing models of motion effects on plasma waves, then identify a number of basic challenges that lie in the way of using these models to quantify motion effects in realistic configurations, and finally discuss possible workarounds.