Substorm Identification With The WINDMI Magnetosphere - Ionosphere
Nonlinear Physics Model
Abstract
We investigate the applicability and performance of the plasma physics
based WINDMI model to the analysis and identification of substorm
onsets. There are several substorm onset criteria that have been
developed into event lists, either from auroral observations or from
auroral electrojet features. Five of these substorm onset lists are
available at the SuperMAG website. We analyze these lists, aggregate
them and use the WINDMI model to assess the identified events,
emphasizing the loading unloading mechanism in substorm dynamics. The
WINDMI model employs eight differential equations utilizing solar wind
data measured at L1 by the ACE satellite as input to generate outputs
such as the geotail current, the ring current and the field-aligned
currents (FACs). In particular, the WINDMI model current output $I_1$
represents the westward auroral electrojet, which is related to the
substorm SML index. We analyze a decade of solar wind and substorm onset
data from 1998 to 2007, encompassing over 15,000 onsets. Our findings
reveal a significant correlation, with WINDMI-derived enhancements in
FAC coinciding with the identified substorm events approximately
40\% of the time. This suggests that a substantial
proportion of substorms may be attributed to solar wind driving that
results in the loading and unloading of energy in the magnetotail.