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MLT Plasmapause Characteristics: Comparison Between THEMIS Observations and Numerical Simulations
Ist Teil von
Journal of geophysical research. Space physics, 2018-03, Vol.123 (3), p.2000-2017
Ort / Verlag
Washington: Blackwell Publishing Ltd
Erscheinungsjahr
2018
Link zum Volltext
Quelle
Wiley Online Library
Beschreibungen/Notizen
We perform a statistical comparison of the global behavior of the THEMIS observed and simulated plasmapause in the geomagnetic equatorial plane. Simulation is based on the interchange instability mechanism. Analyzing plasmapause positions (LPPs) from the period July 2008 to December 2012, we derived formation and propagation characteristics of the main plasmapause, which reflect the most probable global plasmapause behavior. The results suggest a global eastward azimuthal plasmapause propagation and a radial plasmapause motion limited to the 21–07 MLT sector. The formation of the plasmapause takes place with the highest probability at postmidnight. It is likely that the erosion occurs in a range of MLTs simultaneously. On the dayside, the plasmapause moves almost entirely azimuthally. We suggest that the plasmapause propagates azimuthally with a mean angular velocity close to the corotation speed at all MLTs, at least during periods of lower geomagnetic activity. The results also show that the experimental plasmapause characteristics are in accordance with the interchange instability mechanism. Along with the proposed suggestions for future works, this study contributes to making a further step toward resolving some of the long‐lasting, unresolved issues related to plasmapause dynamics.
Key Points
Formation (radial movement) of the main plasmapause (PP) is triggered between 21 and 07 MLT with the highest probability at postmidnight
Main PP moves azimuthally with the velocity close to corotational one
Main PP characteristics inferred from THEMIS measurements and from model predictions based on interchange mechanism are in agreement