Multi-Instrument Characterization of Magnetospheric Cold Plasma Dynamics in the June 22, 2015 Geomagnetic Storm.
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ABSTRACT: We present a comparison of magnetospheric plasma mass/electron density observations during an 11-day interval which includes the geomagnetic storm of June 22, 2015. For this study we used: Equatorial plasma mass density derived from geomagnetic field line resonances (FLRs) detected by Van Allen Probes and at the ground-based magnetometer networks EMMA and CARISMA; in situ electron density inferred by the Neural-network-based Upper hybrid Resonance Determination algorithm applied to plasma wave Van Allen Probes measurements. The combined observations at L ∼ 4, MLT ∼ 16 of the two longitudinally separated magnetometer networks show a temporal pattern very similar to that of the in situ observations: A density decrease by an order of magnitude about 1 day after the Dst minimum, a partial recovery a few hours later, and a new strong decrease soon after. The observations are consistent with the position of the measurement points with respect to the plasmasphere boundary as derived by a plasmapause test particle simulation. A comparison between plasma mass densities derived from ground and in situ FLR observations during favorable conjunctions shows a good agreement. We find however, for L < ∼3, the spacecraft measurements to be higher than the corresponding ground observations with increasing deviation with decreasing L, which might be related to the rapid outbound spacecraft motion in that region. A statistical analysis of the average ion mass using simultaneous spacecraft measurements of mass and electron density indicates values close to 1 amu in plasmasphere and higher values (∼2-3 amu) in plasmatrough.
SUBMITTER: Vellante M
PROVIDER: S-EPMC8365745 | biostudies-literature |
REPOSITORIES: biostudies-literature
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