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Simultaneous Global Ionospheric Disturbances Associated With Penetration Electric Fields During Intense and Minor Solar and Geomagnetic Disturbances
Nishimura, Yukitoshi; Zhang, Shun-Rong; Vierinen, Juha +8 more
A new observational phenomenon, named Simultaneous Global Ionospheric Density Disturbance (SGD), is identified in GNSS total electron content (TEC) data during periods of three typical geospace disturbances: a Coronal Mass Ejection-driven severe disturbance event, a high-speed stream event, and a minor disturbance day with a maximum Kp of 4. SGDs …
Electron Heating Scales in Collisionless Shocks Measured by MMS
Johlander, Andreas; Khotyaintsev, Yuri V.; Dimmock, Andrew P. +2 more
Electron heating at collisionless shocks in space is a combination of adiabatic heating due to large-scale electric and magnetic fields and non-adiabatic scattering by high-frequency fluctuations. The scales at which heating happens hints to what physical processes are taking place. In this letter, we study electron heating scales with data from t…
PIC Simulations of Overstretched Ion-Scale Current Sheets in the Magnetotail
Arnold, H.; Sitnov, M. I.
Onset of reconnection in the tail requires the current sheet thickness to be of the order of the ion thermal gyroradius or smaller. However, existing isotropic plasma models cannot explain the formation of such thin sheets at distances where the X-lines are typically observed. Here we reproduce such thin and long sheets in particle-in-cell simulat…
Electron Rolling-Pin Distributions Preceding Dipolarization Fronts
Cao, J. B.; Liu, C. M.; Xing, X. N.
Electron rolling-pin distribution (RPDs), characterized by triple peaks at pitch angles 0°, 90°, and 180°, have recently been discovered in the terrestrial magnetosphere. Since the RPDs' formation is typically attributed to local betatron acceleration, RPDs have been believed to appear primarily inside strong magnetic regions, such as flux pileup …
Simultaneous Mesoscale Polar Cusp Field-Aligned Currents Measured on Mid- and Low-Altitude Satellites
Dunlop, M. W.; Dong, X. -C.; Xiao, C. +3 more
Using a conjunction of Cluster in the mid-altitude dayside magnetosphere and Swarm in the low-altitude ionosphere, we show, by employing multi-spacecraft analysis, that matched, strong magnetic perturbations and the corresponding mesoscale field-aligned current (FAC) structures are measured in the high latitude polar cusp region during the 7 Octob…
Multispacecraft Observations of the Simultaneous Occurrence of Magnetic Reconnection at High and Low Latitudes During the Passage of a Solar Wind Rotational Discontinuity Embedded in the April 9-11, 2015 ICME
Lugaz, Noé; Escoubet, C. Philippe; Wing, Simon +2 more
Numerous questions remain about how solar wind directional discontinuities, for example, rotational discontinuities (RDs), affect energy and transport processes at the magnetopause. The impact on the dayside magnetosphere of a solar wind RD is studied. The study shows that the RD leads to complex structures at the magnetopause, boundary layer, man…
Undulated Shock Surface Formed After a Shock-Discontinuity Interaction
Shen, Chao; Zhou, Yufei; Ji, Yong
Shock ripples and shock-discontinuity interactions (SDIs) have long been proposed to explain the frequent occurrence of high-speed jets (HSJs) in the magnetosheath; however, there is no direct observational evidence for either of them occurring near a shock. Herein, we report a large-scale, long-duration undulated quasi-perpendicular shock surface…
Probing the Magnetospheric Generator of Quiet Electrostatic Auroral Arcs From Ground Based Optical Observations and Magnetosphere-ionosphere Coupling Modeling
De Keyser, J.; Lamy, H.; Cessateur, G. +2 more
Observations of a quiet electrostatic auroral arc by the ALIS network on 5 March 2008 are used to infer a two-dimensional map of the flux of precipitating energy. Among a family of numerical solutions of a stationary magnetosphere—ionosphere coupling model in which the origin of the arc is a magnetospheric generator interface, we find which genera…