Search Publications
Long- and short-term variability of Saturn's ionic radiation belts
Krupp, N.; Dougherty, M. K.; Jones, G. H. +7 more
Earlier studies of Saturn's inner ionic radiation belts revealed that their content was surprisingly constant while their evolution appeared decoupled from dynamics of the Saturnian magnetosphere. Saturn's icy moons in combination with the neutral gas and dust that surround the planet seem to effectively restrict radial transport of energetic ions…
Kinetic simulations of magnetic reconnection in presence of a background O+ population
Andersson, L.; Lapenta, G.; Markidis, S. +3 more
Particle-in-Cell simulations of magnetic reconnection with an H+ current sheet and a mixed background plasma of H+ and O+ ions are completed using physical mass ratios. Four main results are shown. First, the O+ presence slightly decreases the reconnection rate and the magnetic reconnection evolution dep…
Auroral electron distributions within and close to the Saturn kilometric radiation source region
Schippers, P.; André, N.; Gurnett, D. A. +11 more
On 17 October 2008, Cassini observed for the first time the electron populations associated with the crossing of a Saturn kilometric radiation source region and its surroundings. These observations allow for the first time the constraint and quantification of the high-latitude acceleration processes, the current systems, and the origin of the low-…
Statistics of plasma sheet convection
Østgaard, N.; Juusola, L.; Tanskanen, E.
Determining the characteristics of plasma sheet convection and their response to changes in various solar wind parameters is important for understanding the energy and mass transport, as well as disturbance propagation, through geospace. We use 15 years of data obtained by Geotail, Cluster, and THEMIS to study statistically the characteristics of …
The role of ULF waves interacting with oxygen ions at the outer ring current during storm times
Zong, Q. -G.; Reme, H.; Korth, A. +5 more
The modulations of the outer ring current O+ ion fluxes by ULF Pc5 waves are investigated by multisatellite observations during storm times. The O+ ions have energies up to tens of keV. We concentrate on the process in terms of drift-bounce resonance of O+ ions with ULF standing waves to understand whether the ring…
Dynamics and seasonal variations in Saturn's magnetospheric plasma sheet, as measured by Cassini
Coates, A. J.; Krupp, N.; Dougherty, M. K. +6 more
We analyze electron plasma, energetic ion, and magnetic field data from four almost vertical Cassini passes through the nightside plasma sheet of Saturn (segments of the high-latitude orbits of the spacecraft) separated in two subsets: two passes of identical geometry from January 2007 with Cassini crossing the equatorial plane in the postmidnight…
Energetic storm particle events in coronal mass ejection-driven shocks
Gopalswamy, N.; Yashiro, S.; Mäkelä, P. +2 more
We investigate the variability in the occurrence of energetic storm particle (ESP) events associated with shocks driven by coronal mass ejections (CMEs). The interplanetary shocks were detected during the period from 1996 to 2006. First, we analyze the CME properties near the Sun. The CMEs with an ESP-producing shock are faster ($\langle$VCME…
Proton and hydrogen atom transport in the Martian upper atmosphere with an induced magnetic field
Barabash, S.; Futaana, Y.; Nilsson, H. +6 more
We have applied the Direct Simulation Monte Carlo method to solve the kinetic equation for the H/H+ transport in the upper Martian atmosphere. We calculate the upward H and H+ fluxes, values that can be measured, and the altitude profile of the energy deposition to be used to understand the energy balance in the Martian atmos…
Development of parallel electric fields at the plasma sheet boundary layer
Lysak, Robert L.; Song, Yan
Many measurements of auroral particles, in particular recent measurements from the FAST satellite, indicate that the auroral electron distribution is often broad in energy and field-aligned in pitch angle. Such electrons are seen in conjunction with strong kinetic Alfvén waves with small perpendicular wavelength, and so the aurora produced by thes…
Direct evidence of differences in magnetic rotation rate between Saturn's northern and southern polar regions
Southwood, David
The discovery of a difference in apparent rotation rate between Saturn kilometric radio emission from northern and southern hemispheres leads immediately to the question of whether there is a counterpart detectable in the Saturnian magnetic field. We report direct detection of a difference in the rotating magnetic signal measured by the Cassini sp…