Search Publications
Ion energization and transport associated with magnetic dipolarizations
El-Alaoui, Mostafa; Walker, Raymond J.; Ashour-Abdalla, Maha +1 more
Ion energization in the magnetotail during substorms is examined by simulating a modest substorm event that occurred on 7 February 2009. The simulation scheme combines global magnetohydrodynamic (MHD) modeling of the magnetosphere driven by realistic upstream solar wind conditions, with a large-scale kinetics (LSK) simulation. Multiple earthward p…
Discontinuities in the magnetic field near Enceladus
Dougherty, Michele K.; Saur, Joachim; Kriegel, Hendrik +2 more
The plasma interaction of Saturn's icy moon Enceladus generates a hemisphere coupling current system that directly connects the giant planet's northern and southern polar magnetosphere. Based on Cassini magnetometer observations from all 20 targeted Enceladus flybys between 2004 and 2014, we study the magnetic field discontinuities associated with…
Dayside/nightside asymmetry of ion densities and velocities in Saturn's inner magnetosphere
Wahlund, J. -E.; Morooka, M. W.; Holmberg, M. K. G.
We present Radio and Plasma Wave Science Langmuir probe measurements from 129 Cassini orbits, which show a day/night asymmetry in both ion density and ion velocity in the radial region 4-6 RS (1 RS = 60,268 km) from the center of Saturn. The ion densities ni vary from an average of ∼35 cm-3 around noon u…
Saturn's elusive nightside polar arc
Jackman, C. M.; Milan, S. E.; Fear, R. C. +5 more
Nightside polar arcs are some of the most puzzling auroral emissions at Earth. They are features which extend from the nightside auroral oval into the open magnetic field line region (polar cap), and they represent optical signatures of magnetotail dynamics. Here we report the first observation of an arc at Saturn, which is attached at the nightsi…
Kelvin-Helmholtz unstable magnetotail flow channels: Deceleration and radiation of MHD waves
Turkakin, H.; Mann, I. R.; Rankin, R.
The Kelvin-Helmholtz instability (KHI) of magnetotail flow channels associated with bursty bulk flows (BBFs) is investigated. MHD oscillations of the channel in both kink and sausage modes are investigated for KHI, and both the primary and secondary KHIs are found that drive MHD waves. These instabilities are likely to be important for flow channe…
Particle deposition on the saturnian satellites from ephemeral cryovolcanism on Enceladus
Showman, Adam P.; Hirata, Naoyuki; Miyamoto, Hideaki
The geologically active south pole of Enceladus generates a plume of micron-sized particles, which likely form Saturn's tenuous E-ring extending from the orbit of Mimas to Titan. Interactions between these particles and satellites have been suggested, though only as very thin surficial phenomena. We scrutinize high-resolution images with a newly d…
The current system associated with the boundary of plasma bubbles
Parks, George K.; Zong, Qiu-Gang; Zhao, Duo +7 more
The current system associated with the boundary of plasma bubbles in the Earth's magnetotail has been studied by employing Cluster multipoint observations. We have investigated the currents in both the dipolarization front (DF, leading edge of the plasma bubble) and the trailing edge of the plasma bubble. The distribution of currents at the edge i…
Thermal alteration: A possible reason for the inconsistency between OMEGA/CRISM and TES detections of phyllosilicates on Mars?
Glotch, Timothy D.; Che, Congcong
Previous laboratory analyses have shown that high temperatures can modify the crystal structures of some phyllosilicates in such a way that their spectroscopic signatures appear different from various wavelength perspectives. This may be the case in the Nili Fossae region of Mars, where our analyses indicate that thermally altered (~400°C) Fe-rich…
Detection of a strongly negative surface potential at Saturn's moon Hyperion
Coates, A. J.; Krupp, N.; Dougherty, M. K. +7 more
On 26 September 2005, Cassini conducted its only close targeted flyby of Saturn's small, irregularly shaped moon Hyperion. Approximately 6 min before the closest approach, the electron spectrometer (ELS), part of the Cassini Plasma Spectrometer (CAPS) detected a field-aligned electron population originating from the direction of the moon's surface…
Low-altitude electron acceleration due to multiple flow bursts in the magnetotail
Nilsson, H.; Hamrin, M.; Marghitu, O. +12 more
At 10:00 UT on 25 February 2008, Cluster 1 spacecraft crossed the near-midnight auroral zone, at about 2 RE altitude, while two of the Time History of Events and Macroscale Interactions During Substorms (THEMIS) spacecraft, THD and THE, observed multiple flow bursts on the near-conjugate plasma sheet field lines. The flow shear pattern …