Auroral Signatures of Ballooning Mode Near Substorm Onset: Open Geospace General Circulation Model Simulations

摘要: Auroral Phenomen Other Planets Geophysical Mon © 2012. American 10.1029/2011GM We present results from Open Geospace General Circulation Model simulations of the 23 March 2007 THEMIS “first light” substorm. investigate relation between ballooning modes in tail and auroral “beads.”Magnetic mapping structures shows an ionosphere signature that closely resembles beads. The close match properties with observations, particular azimuthal wavelength ~0.5 RE, resemblance mapped simulation observed beads provides evidence are a modes. Since aurora is much easier globally than tail, this result allows studying to substorm phases using observations. From simulation, we find no direct connection mode expansion phase onset. However, other instabilities lie somewhere tearing may play important role as trigger.