Auroral Signatures of Solar wind Magnetospheric Coupling.

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

The dayside magnetosphere plays a crucial role in controlling the mass and energy in-flow from the solar wind (ionized plasma blown from the Sun). NASA's THEMIS spacecraft were launched into favorable orbits to study the interaction of solar wind with the Earth's magnetosphere. These spacecraft are often positioned so that geomagnetic field lines connect them to the upper atmospheric regions in view of the ground-based observing stations. Relating the satellite data to their auroral footprints has revolutionized abilities to study dynamic processes in the solar wind and geospace. During winter times the high-latitude regions can be permanently in dark permitting optical observations of the aurora even at magnetic midday. As two-dimensional dynamic images of the aurora are signatures of plasma processes operating on the flux tube at some distance above the Earth, the joint studies of the THEMIS plasma data and optical instruments deployed at the South Pole and Automatic Geophysical Observatories in the Antarctic provide a unique opportunity to answer four specific questions: (1) Do existing geomagnetic field models accurately map the dayside magnetospheric boundaries? (2) Are the dayside soft aurora "footprints" of the magnetospheric cusp and whether they occur on open field lines? (3) When do latitudinal motions of the dayside aurora represent in-out motion of the Earth's magnetopause? (4) What is the mechanism responsible for the production of the frequently observed Poleward Moving Auroral Forms? The Antarctic optical observations provide a high-resolution dynamic view of the auroral context related to the in situ satellite measurements; such coordinated data exists from the austral winter of 2007 to today. This research also contributes to the training and education of both the graduate and undergraduate students.