Open AccessDetermination of Auroral Electrodynamic Parameters From AMPERE Field‐Aligned Current Measurements
Author(s) -
Robinson R. M.,
Zanetti Larry,
Anderson Brian,
Vines Sarah,
Gjerloev Jesper
Publication year - 2021
Publication title -
space weather
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 56
ISSN - 1542-7390
DOI - 10.1029/2020sw002677
Subject(s) - substorm , ampere , electric field , physics , ionosphere , computational physics , magnetic field , magnetosphere , current (fluid) , geophysics , field (mathematics) , latitude , mathematics , quantum mechanics , astronomy , pure mathematics , thermodynamics
We calculate high latitude electrodynamic parameters using global maps of field‐aligned currents from the Active Magnetosphere and Planetary Response Experiment (AMPERE). The model is based on previous studies that relate field‐aligned currents to auroral Pedersen and Hall conductances measured by incoherent scatter radar. The field‐aligned currents and conductances are used to solve for the electric potential at high latitudes from which electric fields are computed. The electric fields are then used with the conductances to calculate horizontal ionospheric currents. We validate the results by simulating the SuperMAG magnetic indices for 30 geomagnetically active days. The correlation coefficients between derived and actual magnetic indices were 0.68, 0.76, and 0.84 for the SMU, SML, and SME indices, respectively. We show examples of times when the simulations differ markedly from the measured indices and attribute them to either small‐scale, substorm‐related current structures or the effects of neutral winds. Overall, the performance of the model demonstrates that with few exceptions, auroral electrodynamic parameters can be accurately deduced from the global field‐aligned current distribution provided by AMPERE.