Observation of Small-Scale Magnetic and Current Structures During Prolonged Dipolarizations in the Near Geomagnetic Tail by MMS Mission

• Published in: Plasma physics reports 2021-05, Vol.47 (5), p.427-439
• Main Authors: Malykhin, A. Yu, Grigorenko, E. E.
• Format: Article
• Language: English
• Subjects: Atomic; Geomagnetic tail; Geomagnetism; Molecular; Optical and Plasma Physics; Physics; Physics and Astronomy; Propagation; Propagation velocity; Space Plasma
• ISSN: 1063-780X; 1562-6938
• DOI: 10.1134/S1063780X21050068

Observations of two successive prolonged dipolarizations in the geomagnetic tail (at a distance of X ~ –18.3 R E from the Earth, where R E is the Earth’s radius) according to the data obtained by the MMS mission are presented and analyzed. Eight dipolarization fronts (DF) were identified during these dipolarizations, and their propagation velocities and spatial scale were determined. The DF propagation velocities were found to be in the range between 130 and 360 km/s. The spatial scale of quasi-isolated DFs in the direction of their propagation at the beginning of the first dipolarization was ~1ρ i (where ρ i is the ion gyroradius), while the spatial scale of DFs observed in the flux pile up region was ~5ρ i . Using methods of multi-spacecraft observation, densities of electric currents related to DFs were determined on a sub-ion scale. It is demonstrated that thin ( ) intense electron current structures with amplitudes of current density varying from 10 to 60 nA/m 2 that form complex multi-scale three-dimensional configurations are observed simultaneously with the DFs.