Earth's ion upflow associated with polar cap patches: Global and in situ observations

Qing‐He Zhang,Evan G Thomas,Yong‐Liang Zhang,Rui‐Yuan Liu,Jøran Moen,Yu‐Zhang Ma,Roderick A Heelis,J Michael Ruohoniemi,Yong C.‐M Liu,Jun Liang,Marc Hairston,Qiu‐Gang Zong,Ian Mccrea,Shun‐Rong Zhang,Michael Lockwood,Mark Lester,Bei‐Chen Zhang,Malcolm W Dunlop

doi:10.1002/2016gl067897

Abstract

AbstractWe report simultaneous global monitoring of a patch of ionization and in situ observation of ion upflow at the center of the polar cap region during a geomagnetic storm. Our observations indicate strong fluxes of upwelling O+ ions originating from frictional heating produced by rapid antisunward flow of the plasma patch. The statistical results from the crossings of the central polar cap region by Defense Meteorological Satellite Program F16–F18 from 2010 to 2013 confirm that the field‐aligned flow can turn upward when rapid antisunward flows appear, with consequent significant frictional heating of the ions, which overcomes the gravity effect. We suggest that such rapidly moving patches can provide an important source of upwelling ions in a region where downward flows are usually expected. These observations give new insight into the processes of ionosphere‐magnetosphere coupling.

Highlights

Ion outflow from the Earth’s ionosphere is an important aspect of magnetosphere-ionosphere-thermosphere coupling, as it provides a significant, and at times dominant, source of magnetospheric plasma [Shelley et al, 1972; Lockwood and Titheridge, 1981; Yau and Andre, 1997; Andre and Yau, 1997; Moore et al, 1997; Chappell et al, 2000]
Our observations indicate strong fluxes of upwelling O+ ions originating from frictional heating produced by rapid antisunward flow of the plasma patch
Southward interplanetary magnetic field (IMF) intervals favor rapid reconnection at the dayside magnetopause and are expected to generate pulsed ionospheric flows [Zhang et al, 2011b], which have frequently been implicated in patch production [Lockwood and Carlson, 1992; Zhang et al, 2011a]

Summary

Introduction

Ion outflow from the Earth’s ionosphere is an important aspect of magnetosphere-ionosphere-thermosphere coupling, as it provides a significant, and at times dominant, source of magnetospheric plasma [Shelley et al, 1972; Lockwood and Titheridge, 1981; Yau and Andre, 1997; Andre and Yau, 1997; Moore et al, 1997; Chappell et al, 2000]. Such outflow potentially has a global impact on the entire Sun-Earth system through its ability to affect plasma transport and convection in the magnetosphere. Ion upflow occurs mainly at low altitude with thermal velocities and serve as the source for ion outflow at high altitudes where the ions achieve escape velocities

Results

Discussion

Conclusion