Plasma Seminar: Magnetotail-Ionosphere Coupling in Fast Flow Channels

Oliver Brambles, Thayer School of Engineering

Tuesday, March 6, 2012, 3:30pm

Cummings 200

The closure of open magnetic flux in the magnetotail by magnetic reconnection generates fast flows in the plasma sheet. These flows occur in a sequence of short bursts and have been found to be localized between 2100 and 0100 MLT, peaking in the duskside, pre-midnight sector. Auroral substorm expansions and the Alfvénic aurora show similar local time distributions to the fast flows in the plasma sheet. Controlled simulations using the LFM global model show that the dawn-dusk asymmetry of the fast flow channels and Alfvénic aurora is regulated by the spatial variation in ionospheric conductance. This asymmetry disappears when the conductance is taken to be spatially uniform. Furthermore, non-physical spatial variations in the ionospheric conductances can be used to produce fast flows which are predominantly on the dawn side. This talk will examine how the gradients in the ionospheric conductance affect the distribution of fast flows in the plasma sheet.