Initial Observations of Storm-Time and Disturbance Electric Fields in the Subauroral and Mid-Latitude Ionospheres Using the SuperDARN-Storm Radar at Wallops Island, VA

In May of 2005, the Johns Hopkins University Applied Physics Laboratory in collaboration with the Goddard Space Flight Center Wallops Flight Facility began operation of a new SuperDARN radar located near the Wallops Island sounding rocket launch site. The radar is the first of the SuperDARN network that has been sited at a mid-latitude location from which it can detect electron density irregularities produced by ionospheric electric fields and density gradients during disturbed geomagnetic conditions with particular emphasis on geomagnetic storms. The radar scans over a 52 degree azimuth sector that extends over much of the North Atlantic Ocean and has spatial and temporal resolutions of ~50 km and 1-2 minutes. Doppler information from the backscattered signals is used to determine the spatial structure and temporal variability of electric fields and plasma convection in the low-latitude portion of the auroral, subauroral and mid-latitude ionospheres. Since the radar began operations, there have been significant geomagnetic storms on May 15th, June 12th, June 23rd, August 24th, and August 31st of the present year. There have also been a number of other days that have displayed strong non-storm disturbances. Using these events we have been able to identify storm-enhanced convection electric fields at all local times and a broad range of latitudes extending from 50-70 degrees geomagnetic. In this paper, we present examples of penetrating electric fields at a number of local times as well as midnight sector subauroral flow enhancements that are very similar to the SAID events observed with low-altitude spacecraft. One of the unique aspects of the later phenomena is that the Wallops radar allows us to observe the growth and decay of SAID-type flows.