ASHLEY: A new empirical model for the high-latitude electron
precipitation and electric field
Abstract
In this study, a new high-latitude empirical model is introduced, named
for Auroral energy Spectrum and High-Latitude Electric field variabilitY
(ASHLEY). This model aims to improve specifications of soft electron
precipitations and electric field variability that are not well
represented in existing high-latitude empirical models. ASHLEY consists
of three components, ASHLEY-A, ASHLEY-E and ASHLEY-Evar, which are
developed based on the electron precipitation and bulk ion drift
measurements from the Defense Meteorological Satellite Program (DMSP)
satellites during the most recent solar cycle. On the one hand, unlike
most existing high-latitude electron precipitation models, which have
assumptions about the energy spectrum of incident electrons, the
electron precipitation component of ASHLEY, ASHLEY-A, provides the
differential energy fluxes in the 19 DMSP energy channels under
different geophysical conditions without making any assumptions about
the energy spectrum. It has been found that the relaxation of spectral
assumptions significantly improves soft electron precipitation
specifications with respect to a Maxwellian spectrum (up to several
orders of magnitude). On the other hand, ASHLEY provides consistent mean
electric field and electric field variability under different
geophysical conditions by ASHLEY-E and ASHLEY-Evar components,
respectively. This is different from most existing electric field models
which only focus on the large-scale mean electric field and ignore the
electric field variability. Furthermore, the consistency between the
electric field and electron precipitation is better taken into account
in ASHLEY.