Search Publications
Warm flux tubes in the E-ring plasma torus: Initial Cassini magnetometer observations
André, N.; Russell, C. T.; Dougherty, M. K. +2 more
Initial Cassini magnetometer observations in the E-ring plasma torus reveal the presence of previously unreported diamagnetic decreases in the magnetic field. The decrease in magnetic pressure on these flux tubes implies the presence of additional plasma energy densities up to 1 keV/cm3. They are less stretched than surrounding flux tub…
Discovery of nitrogen in Saturn's inner magnetosphere
Johnson, R. E.; Sittler, E. C.; Smith, H. T. +6 more
We detected N+ in Saturn's magnetosphere in the range L ~ 3.5 to ~9.5 Saturn Radii (Rs) using data collected by the Cassini Plasma Spectrometer during Saturn Orbit Insertion and the following orbit (Rev A). The presence of N+ in Saturn's magnetosphere has been a source of much debate since Voyager's detection of unresolved ma…
Evidence of Enceladus and Tethys microsignatures
Livi, S.; Krupp, N.; Woch, J. +7 more
We present evidence of two icy satellite microsignatures in the Cassini LEMMS data. Just upstream of Enceladus, a deep and narrow decrease in the flux of several MeV electrons is consistent with a recent absorption by that moon. This microsignature is collocated with a deep depletion in the MeV proton flux. The proton feature is much wider than th…
Low energy electron microsignatures at the orbit of Tethys: Cassini MIMI/LEMMS observations
Livi, S.; Krupp, N.; Woch, J. +10 more
We report on low energy electron microsignature observations by the Low Energy Magnetospheric Measurement System (LEMMS) in the vicinity of Tethys's L-shell, during the first seven orbits of the Cassini mission. Tethys, due to its large size, is the source of strong microsignatures. Shallower absorption features seen are the result of aged Tethys …
Magnetosheath variations during the storm main phase on 20 November 2003: Evidence for solar wind density control of energy transfer to the magnetosphere
Ebihara, Y.; Kataoka, R.; Sibeck, D. G. +4 more
Energy transfer from the solar wind into the magnetosphere and ionosphere is controlled by the southward magnetic field in the magnetosheath which under normal high Mach number conditions is about four times the solar wind southward field. In a low Mach number regime, however, the magnetosheath compression is diminished by a low solar wind density…
Generation of downshifted oscillations in the electron foreshock: A loss-cone instability
Schwartz, S. J.; Fazakerley, A.; Décréau, P. +4 more
Measurements performed aboard Cluster spacecraft near Earth's bow shock on 24 January 2001 provide convincing evidence of a loss-cone feature within the electron foreshock region. This feature is formed by suprathermal electrons with energies 15-45 eV and pitch angles 130°-150° and is always accompanied by electrostatic waves with frequencies well…
High spectral and temporal resolution observations of Saturn kilometric radiation
Gurnett, D. A.; Hospodarsky, G. B.; Kurth, W. S. +7 more
This paper presents the first high-resolution dynamic spectra of Saturn kilometric radiation acquired upon Cassini's approach and first orbits of Saturn. The emissions display upward and downward drifting features with bandwidths down to ~200 Hz and drift rates of a few kHz per second. At other times, the emissions are much more diffuse or continu…
A new model of total solar irradiance based on sunspot areas
Walton, Stephen R.; Preminger, Dora G.
We show that daily sunspot area can be used in a simple model to reconstruct daily variations in the total solar irradiance, S. The model assumes that all fluctuations in S are correlated with the emergence of sunspots on the solar disk. Cotemporal data for S and sunspot area are analysed to extract the finite impulse response function that descri…
An update on the ring exosphere and plasma disc of Saturn
Ip, W. -H.
A re-examination of the mass budget of the ring exosphere of Saturn - as prompted by the most recent Cassini measurements in the vicinity of the ring system - indicates that the corresponding number density could reach the level of 2-3 × 105 cm-3 at maximum. Such extended exospheric structure in equilibrium with a thin ring p…
Small rampart craters in an equatorial region on Mars: Implications for near-surface water or ice
Jaumann, R.; Neukum, G.; Hauber, E. +3 more
Small onset diameters (1 km) of rampart craters were identified in High Resolution Stereo Camera (HRSC) imagery in the equatorial region of the Valles Marineris plateaus. This is in contrast to previous global studies based on Viking imagery, which showed onset diameters in the range of 4 km to 7 km in equatorial regions. The observed small rampar…