Search Publications
Deflected propagation of a coronal mass ejection from the corona to interplanetary space
Wang, Yuming; Shen, Fang; Shen, Chenglong +2 more
Among various factors affecting the space weather effects of a coronal mass ejection (CME), its propagation trajectory in the interplanetary space is an important one determining whether and when the CME will hit the Earth. Many direct observations have revealed that a CME may not propagate along a straight trajectory in the corona, but whether or…
Consequences of geomagnetic activity on energization and loss of radiation belt electrons by oblique chorus waves
Krasnoselskikh, V.; Artemyev, A. V.; Agapitov, O. V. +1 more
Statistics of amplitudes and obliquity of lower band chorus whistler mode waves have been obtained from Cluster measurements in Earth's outer radiation belt and fitted as functions of L, latitude, magnetic local time, and three geomagnetic activity ranges for Dst∈[+10,-80] nT. Very oblique chorus waves have generally a much smaller average intensi…
Field-aligned currents in Saturn's southern nightside magnetosphere: Subcorotation and planetary period oscillation components
Coates, A. J.; Dougherty, M. K.; Alexeev, I. I. +6 more
We investigate magnetic data showing the presence of field-aligned magnetosphere-ionosphere coupling currents on 31 Cassini passes across Saturn's southern postmidnight auroral region. The currents are strongly modulated in magnitude, form, and position by the phase of the southern planetary period oscillations (PPOs). PPO-independent currents are…
Evolution of the 12 July 2012 CME from the Sun to the Earth: Data-constrained three-dimensional MHD simulations
Hess, Phillip; Wang, Yuming; Shen, Fang +5 more
The dynamic process of coronal mass ejections (CMEs) in the heliosphere provides us the key information for evaluating CMEs' geoeffectiveness and improving the accurate prediction of CME-induced shock arrival time at the Earth. We present a data-constrained three-dimensional (3-D) magnetohydrodynamic (MHD) simulation of the evolution of the CME in…
The kinetic ballooning/interchange instability as a source of dipolarization fronts and auroral streamers
Pritchett, P. L.; Coroniti, F. V.; Nishimura, Y.
The possibility that the dipolarization fronts (DFs) observed in the plasma sheet could be produced by the ballooning/interchange instability is explored using three-dimensional electromagnetic particle-in-cell simulations. The localized interchange heads produced in the nonlinear stage of the instability exhibit the main near-equatorial propertie…
Interaction of magnetic reconnection and Kelvin-Helmholtz modes for large magnetic shear: 1. Kelvin-Helmholtz trigger
Ma, Xuanye; Otto, Antonius; Delamere, Peter A.
At the Earth's magnetopause, both magnetic reconnection and the Kelvin-Helmholtz (KH) instability can operate simultaneously for southward interplanetary magnetic field conditions. The dynamic evolution of such a system can be expected to depend on the importance of KH wave evolution versus reconnection and therefore on the respective initial pert…
Saturn's dynamic magnetotail: A comprehensive magnetic field and plasma survey of plasmoids and traveling compression regions and their role in global magnetospheric dynamics
Dougherty, M. K.; Thomsen, M. F.; Jackman, C. M. +8 more
We present a comprehensive study of the magnetic field and plasma signatures of reconnection events observed with the Cassini spacecraft during the tail orbits of 2006. We examine their "local" properties in terms of magnetic field reconfiguration and changing plasma flows. We also describe the "global" impact of reconnection in terms of the contr…
Magnetic reconnection, buoyancy, and flapping motions in magnetotail explosions
Merkin, V. G.; Sitnov, M. I.; Mauk, B. H. +5 more
A key process in the interaction of magnetospheres with the solar wind is the explosive release of energy stored in the magnetotail. Based on observational evidence, magnetic reconnection is widely believed to be responsible. However, the very possibility of spontaneous reconnection in collisionless magnetotail plasmas has been questioned in kinet…
The substorm current wedge: Further insights from MHD simulations
Hesse, M.; Birn, J.
Using a recent magnetohydrodynamic simulation of magnetotail dynamics, we further investigate the buildup and evolution of the substorm current wedge (SCW), resulting from flow bursts generated by near-tail reconnection. Each flow burst generates an individual current wedge, which includes the reduction of cross-tail current and the diversion to r…
Observation of large-amplitude magnetosonic waves at dipolarization fronts
Nishimura, Yukitoshi; Yuan, Zhigang; Huang, Shiyong +6 more
Various plasma waves have been observed in the vicinity of dipolarization fronts (DFs) and the rarefaction regions behind them. It was suggested that these waves not only play crucial roles in regulating particle kinetics at the DFs but also may potentially affect the large-scale dynamics of the magnetotail. In this paper, we present the observati…