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In Situ Observational Evidence of the Polar Cap Arc at 1500 MLT (15MLT-PCA) Associated With the Lobe Reconnection
Shi, Run; Han, Desheng; Feng, Huiting +4 more
The polar cap arc at 1500 MLT (15MLT-PCA) has been considered as an auroral signature of the cusp's duskside boundary and been speculated to be caused by lobe reconnection. However, no observational evidence has been provided to support this speculation. Here we report a 15MLT-PCA event occurred on 29 November 2017 using multi-instrument observati…
On the Response of Protons to Dynamical Reconfigurations of Mercury's Magnetosphere
Hadid, L. Z.; Aizawa, S.; Delcourt, D.
We examine the dynamics of protons during tail-like to dipole-like reconfigurations of Mercury's magnetosphere. Such reconfigurations that frequently occur in the highly dynamical Hermean environment are accompanied by induced electric fields leading to short-lived convection enhancements. Using test particle calculations, we show that, under the …
Repeated and Long-Lasting Fault Activation on Amazonian Mars as Demonstrated by Tectonically Induced Landslides
Fawdon, P.; Balme, M. R.; Rothery, D. A. +1 more
We identify and analyze a large shortening structure (surface expression of a thrust fault) in western Arabia Terra, Mars, exhibiting recent, repeated, and long-lasting tectonic activity. Where the fault system deforms Marsabit crater rim, four landslides with differing degradation states extend onto the crater floor. We propose these were trigger…
Impact of the Turbulent Vertical Mixing on Chemical and Cloud Species in the Venus Cloud Layer
Marcq, Emmanuel; Stolzenbach, Aurélien; Lefèvre, Franck +3 more
The Venusian atmosphere hosts a 10 km deep convective layer that has been studied by various spacecrafts. However, the impact of the strong vertical mixing on the chemistry of this region is still unknown. This study presents the first realistic coupling between resolved small-scale turbulence and a chemical network. The resulting vertical mixing …
Changes in the Plasma Sheet Conditions at Europa's Orbit Retrieved From Lead Angle of the Satellite Auroral Footprints
Tsuchiya, Fuminori; Kasaba, Yasumasa; Nichols, Jonathan D. +5 more
The electromagnetic interaction between Europa and the plasma sheet in the Jovian magnetosphere generates Alfvén waves, ultimately generating auroral footprints in Jupiter's atmosphere. The position of Europa's auroral footprint is a proxy for travel time of the Alfvén waves. We measured Europa's footprint position using the far-ultraviolet images…
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…
On the Relation Between Jupiter's Aurora and the Dawnside Current Sheet
Wei, Y.; Delamere, P. A.; Badman, S. V. +10 more
Jupiter's auroral emission is a spectacular phenomenon that provides insight into energy release processes related to the coupling of its magnetosphere and ionosphere. This energy release is influenced by solar wind conditions. Using joint observations from Juno and the Hubble Space Telescope (HST), we statistically investigate the relationship be…
Quantification of Carbonates, Oxychlorines, and Chlorine Generated by Heterogeneous Electrochemistry Induced by Martian Dust Activity
Olsen, Kevin S.; Wang, Alian; Jackson, Andrew W. +4 more
Heterogeneous electrochemistry induced by Martian dust activity is an important type of atmosphere-surface interaction that affects geochemical processes at the Martian surface and in the Martian atmosphere. We have experimentally demonstrated that heterogeneous electrochemistry stimulated by mid-strength dust events can decompose common chloride …
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…