Search Publications
Enceladus's internal ocean and ice shell constrained from Cassini gravity, shape, and libration data
Bourgeois, Olivier; Massé, Marion; Čadek, Ondřej +8 more
The intense plume activity at the South Pole of Enceladus together with the recent detection of libration hints at an internal water ocean underneath the outer ice shell. However, the interpretation of gravity, shape, and libration data leads to contradicting results regarding the depth of ocean/ice interface and the total volume of the ocean. Her…
Mass loading at 67P/Churyumov-Gerasimenko: A case study
Behar, E.; Nilsson, H.; Richter, I. +3 more
We study the dynamics of the interaction between the solar wind ions and a partially ionized atmosphere around a comet, at a distance of 2.88 AU from the Sun during a period of low nucleus activity. Comparing particle data and magnetic field data for a case study, we highlight the prime role of the solar wind electric field in the cometary ion dyn…
Flux transfer event observation at Saturn's dayside magnetopause by the Cassini spacecraft
Coates, Andrew J.; Arridge, Christopher S.; Waite, J. Hunter +6 more
We present the first observation of a flux rope at Saturn's dayside magnetopause. This is an important result because it shows that the Saturnian magnetopause is conducive to multiple X-line reconnection and flux rope generation. Minimum variance analysis shows that the magnetic signature is consistent with a flux rope. The magnetic observations w…
A comparative study of dipolarization fronts at MMS and Cluster
Russell, C. T.; Anderson, B. J.; Nakamura, R. +15 more
We present a statistical study of dipolarization fronts (DFs), using magnetic field data from MMS and Cluster, at radial distances below 12 RE and 20 RE, respectively. Assuming that the DFs have a semicircular cross section and are propelled by the magnetic tension force, we used multispacecraft observations to determine the …
Weakening of Jupiter's main auroral emission during January 2014
Fujimoto, M.; Yoshioka, K.; Steffl, A. J. +13 more
In January 2014 Jupiter's FUV main auroral oval decreased its emitted power by 70% and shifted equatorward by ∼1°. Intense, low-latitude features were also detected. The decrease in emitted power is attributed to a decrease in auroral current density rather than electron energy. This could be caused by a decrease in the source electron density, an…
Estimation of bounce resonant scattering by fast magnetosonic waves
Shprits, Yuri Y.
In this study we present calculation of bounce resonant scattering of near equatorially mirroring electrons by fast magnetosonic waves. We first explore the sensitivity of the scattering rates and estimated time scales to a different number of resonances included into calculations. We then explore the sensitivity of calculated rates to the assumed…
Cold ion heating at the dayside magnetopause during magnetic reconnection
Lavraud, B.; André, M.; Vaivads, A. +5 more
Cold ions of ionospheric origin are known to be present in the magnetospheric side of the Earth's magnetopause. They can be very abundant, with densities up to 100 cm-3. These cold ions can mass load the magnetosphere, changing global parameters of magnetic reconnection, like the Alfvén speed or the reconnection rate. In addition they i…
Effects of the crustal magnetic fields on the Martian atmospheric ion escape rate
Barabash, Stas; Nilsson, Hans; Holmström, Mats +2 more
Eight years (2007-2015) of ion flux measurements from Mars Express are used to statistically investigate the influence of the Martian magnetic crustal fields on the atmospheric ion escape rate. We combine all Analyzer of Space Plasmas and Energetic Atoms/Ion Mass Analyzer (ASPERA-3/IMA) measurements taken during nominal upstream solar wind and sol…
Mirror mode structures ahead of dipolarization front near the neutral sheet observed by Cluster
Zhang, T. L.; Nakamura, R.; Baumjohann, W. +4 more
Magnetic compressional structures ahead of a dipolarization front (DF) on 30 August 2002 are investigated by using Cluster data. Our findings are as follows: (1) the structures, observed near the neutral sheet, are mainly compressional and dominant in BZ; (2) they are almost nonpropagating relative to the local ion bulk flow and their l…
Transient, small-scale field-aligned currents in the plasma sheet boundary layer during storm time substorms
Russell, C. T.; Lavraud, B.; Anderson, B. J. +39 more
We report on field-aligned current observations by the four Magnetospheric Multiscale (MMS) spacecraft near the plasma sheet boundary layer (PSBL) during two major substorms on 23 June 2015. Small-scale field-aligned currents were found embedded in fluctuating PSBL flux tubes near the separatrix region. We resolve, for the first time, short-lived …