Plasmapause location under quiet geomagnetic conditions (<i>K</i><i>p</i> ≤ 1): THEMIS observations

Abstract

Abstract We statistically examined the plasmapause location ( L pp ) under quiet geomagnetic conditions ( K p ≤ 1) using the electron density inferred from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft potential for 2 year period (2008 and 2009). Five hundred forty‐three L pp samples were identified under steady quiet conditions with K p values ≤ 1 during 12 h prior to the plasmapause crossing. From our large data set, we determined the medians and means of L pp in L and magnetic local time (MLT). They are located near geosynchronous orbit and nearly circular. The L pp medians show a slight bulge located in postdusk sector. Comparing with previous models, our median or mean L pp is extended ∼1–2 L from the Earth than the model L pp along the local time from 0800 to 2400 MLT. That is, L pp locations in the previous models are underestimated during quiet geomagnetic conditions.