Search Publications
Highly structured electron anisotropy in collisionless reconnection exhausts
Torbert, R. B.; Li, G.; Chen, L. -J. +6 more
Results from two-dimensional particle-in-cell simulations of collisionless magnetic reconnection with zero guide field discussed in this paper reveal that around the time when the reconnection rate peaks, electron velocity distributions become highly structured in magnetic islands and open exhausts. Rings, arcs, and counterstreaming beams are gene…
Enhanced ionization of the Martian nightside ionosphere during solar energetic particle events
Gurnett, D. A.; Futaana, Y.; Němec, F. +2 more
Electron densities in the Martian nightside ionosphere are more than 90% of time too low to be detected by the Mars Advanced Radar for Subsurface and Ionosphere Sounding radar sounder on board the Mars Express spacecraft. However, the relative number of ionograms with peak electron density high enough to be detected represents a good statistical p…
Increases in plasma sheet temperature with solar wind driving during substorm growth phases
Jackman, C. M.; Dandouras, I.; Fazakerley, A. N. +10 more
During substorm growth phases, magnetic reconnection at the magnetopause extracts ~1015 J from the solar wind which is then stored in the magnetotail lobes. Plasma sheet pressure increases to balance magnetic flux density increases in the lobes. Here we examine plasma sheet pressure, density, and temperature during substorm growth phase…
Evidence of strong energetic ion acceleration in the near-Earth magnetotail
Fränz, M.; Wei, Y.; Daly, P. W. +6 more
Until now it is still questionable whether ions are accelerated to energies above 100 keV in the near-Earth current sheet (CS), in the vicinity of a possible near-Earth neutral line. By using 11 years of 3-D energetic ion flux data for protons, helium, and oxygen (~150 keV-1 MeV) from the RAPID instrument on board Cluster 4, we statistically study…
Can magnetopause reconnection drive Saturn's magnetosphere?
Coates, A. J.; Russell, C. T.; Dougherty, M. K. +3 more
While solar wind-driven compression of Saturn's magnetosphere is an important trigger of magnetospheric dynamics, the importance of magnetopause reconnection has been the subject of debate. Here we use Cassini observations at Saturn's magnetopause to address this open issue. Measured conditions at the boundary suggest a typical reconnection electr…
Fresh exposures of hydrous Fe-bearing amorphous silicates on Mars
Weitz, Catherine M.; Bishop, Janice L.; Baker, Leslie L. +1 more
We have discovered relatively fresh exposures of a hydrated, amorphous material along the wall rock slopes in Coprates Chasma, Mars. Visible and near-infrared reflectance spectra extracted from the deposits exhibit broad absorptions around 1.42, 1.94, and 2.25 µm that are most consistent with laboratory spectra of nanophase hydrated Fe-rich alloph…
The scale of the magnetotail reconnecting current sheet in the presence of O+
Kistler, L. M.; Mouikis, C. G.; Liu, Y. H. +2 more
The reconnection current layer thickness is expected to scale with either the ion inertial length or the ion gyroradius. Both of these quantities scale with the mass of the ions present. During geomagnetically disturbed times, the reconnection layer in the magnetotail can contain a significant amount of O+. Using Cluster multi-spacecraf…
Discrepancy between ionopause and photoelectron boundary determined from Mars Express measurements
Barabash, S.; Wei, Y.; Andrews, D. J. +9 more
The Martian ionosphere directly interacts with the solar wind due to lack of a significant intrinsic magnetic field, and an interface is formed in between. The interface is usually recognized by two kinds of indicators: the ionopause identified from ionospheric density profiles and the photoelectron boundary (PEB) determined from the electron ener…
Nanodust detection near 1 AU from spectral analysis of Cassini/Radio and Plasma Wave Science data
Schippers, P.; André, N.; Kurth, W. S. +3 more
Nanodust grains of a few nanometers in size are produced near the Sun by collisional breakup of larger grains and picked up by the magnetized solar wind. They have so far been detected at 1 AU by only the two STEREO spacecraft. Here we analyze the spectra measured by the radio and plasma wave instrument onboard Cassini during the cruise phase clos…
The ionosphere of Saturn as observed by the Cassini Radio Science System
Anabtawi, Aseel; Barbinis, Elias; Fleischman, Don +5 more
Fifty-nine ionsopheric radio occultation observations of the vertical electron density profile in the Saturn ionosphere have been made since the Cassini spacecraft was inserted in orbit around Saturn in 2004. Significant orbit to orbit variations were observed, but the general trend noted in earlier orbits, namely, increasing electron densities wi…