2011 SuperDARN Workshop       

Hemispheric Comparison of Signatures of Flux Transfer Events

K.A. McWilliams and M.R. Wessel
University of Saskatchewan, Saskatoon, Canada

abstract. A previous statistical study of flux transfer events (FTEs) observed by spacecraft during magnetopause crossings has noted that FTEs were observed only in the winter hemisphere (Korotova & Sibeck, GRL, 2008). It was expected that, since an open field line is created in both the summer and the winter hemispheres, FTE signatures would be observed in both hemispheres. The present study is an investigation of the SuperDARN signature of FTEs. Ten years of northern hemisphere data were inspected to assess the seasonal occurrence rate of poleward moving radar auroral forms (PMRAFs). The occurrence of PMRAFs follows very closely the overall occurrence of ionospheric echoes. In addition to this, simultaneous and magnetically conjugate observations of PMRAFs do occur. These ground-based results suggest that the assymmetry in FTE occurrence at the magnetopause is not indicative of a lack of reconnected flux tubes in the winter hemisphere; rather it indicates that the commonly used 'bipolar' magnetic field oscillation that is used to identify reconnected flux tubes is not present.

Sakaguchi KaoriNICT Japan