2011 SuperDARN Workshop
MSTIDs observed with SuperDARN
E.S. Miller and E.R. Talaat
Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA
abstract. The term "Medium Scale Traveling Ionospheric Disturbance" (MSTID) can refer to at least two distinct proposed phenomena: 1. a thermospheric acoustic gravity wave that causes density and height variations in the ionosphere via collisional and density/ionization effects; or 2. an electrified structure due to a plasma instability related to the model presented by Perkins. In this work, we present examples of the signatures of both kinds of structures in SuperDARN backscatter data. Finally, we comment on observational support for the recent theory of Kelley that the so-called "Perkins orientation" of electrified MSTIDs is due to minimization of Joule damping as gravity waves reach the middle latitudes.