Search Publications
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…
Excitation of Saturnian ECH Waves Within Remote Plasma Injections: Cassini Observations
Ni, Binbin; Gu, Xudong; Cao, Xing +7 more
Based on Cassini observations, we report representative electrostatic electron cyclotron harmonic (ECH) wave events observed in Saturn's magnetosphere within remote plasma injections. Unlike local injections, remote injections are "older" injection events that have evolved to form a dispersed signature in particle energy spectrum. We show that Sat…
A Tectonic Origin for the Largest Marsquake Observed by InSight
Wilson, Colin; Lucas, Antoine; Tirsch, Daniela +23 more
The S1222a marsquake detected by InSight on 4 May 2022 was the largest of the mission, at MwMa 4.7. Given its resemblance to two other large seismic events (S1000a and S1094b), which were associated with the formation of fresh craters, we undertook a search for a fresh crater associated with S1222a. Such a crater would be exp…
Solar Control of the Pickup Ion Plume in the Dayside Magnetosheath of Venus
Xu, Qi; Zuo, Pingbing; Xu, Xiaojun +3 more
Using the 8.5-year Venus Express measurements, we demonstrate the asymmetric plasma distributions in the Venusian magnetosheath. An escaping plume is formed by pickup oxygen ions in the hemisphere where the motional electric field points outward from Venus, while the velocity of solar wind protons is faster in the opposite hemisphere. The pickup O…
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 …
Global Spatial Distribution of Hack's Law Exponent on Mars Consistent With Early Arid Climate
Luo, W.; Howard, A. D.; Craddock, R. A. +2 more
Widespread valley networks (VNs) on Mars and other evidence point to an early warm and wet climate. However, ongoing debates still exist about VN's formation processes and associated climatic conditions. The power law relationship between basin length and area (Hack's Law) can be diagnostic of different fluvial processes related to climatic condit…