Empirical Orthogonal Functions, IMF Dependence, and other Statistics for Auroral Poynting Flux derived from FAST Data, with a Cusp Signature

Abstract:

An IMF-dependent empirical model for the Poynting flux (PF) associated with Auroral processes has been contructed from FAST satellite data, along with various statistical characterizations, such as empirical orthoganol functions for the spatial distribution, and an IMF-compensated variability histrogram. Basic findings to be presented include verification of the importance of the auroral electrojets as features of auroral PF deposition and identification of the cusp as a third important feature. The cusp makes an important contribution to the overall energy budget when the IMF is north of ˙90 degrees. The statistical distribution of the PF about the model is heavy tailed, suggesting that there are important and complex dynamical processes not directly controlled by the IMF. For illustration, certain individual PF events from the Polar cap and elsewhere will be presented and compared with the statistical model prediction.