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Heliospheric magnetic field polarity inversions driven by radial velocity field structures
Landi, Simone; Hellinger, Petr; Velli, Marco
Magnetic field polarity inversions embedded in the predominantly unipolar fast solar wind have been observed by the Ulysses spacecraft at high latitudes. Such reversals have the nature of folded back field lines which we suggest are generated by the interaction of standard large amplitude, low frequency, Alfvénic turbulence with velocity shears in…
Do BBFs contribute to inner magnetosphere dipolarizations: Concurrent Cluster and Double Star observations
Zhang, T. L.; Klecker, B.; Nakamura, R. +7 more
We examined the relationship between bursty bulk flow (BBF) events observed by Cluster between -19 RE < X < -12 RE and dipolarization events observed by Double Star TC1 between -13 RE < X < -6 RE. TC1 observed dipolarizations for ~33% of the cases when BBFs were observed by Cluster. During th…
Ulysses observations of very different heliospheric structure during the declining phase of solar activity cycle 23
McComas, D. J.; Gosling, J. T.; Elliott, H. A. +1 more
This study examines the most recent observations from the solar wind experiment (SWOOPS) on the Ulysses spacecraft. In contrast to observations over the same locations in the declining phase of the previous solar activity cycle, these data show a more complicated heliospheric structure. Around the start of 2003, a band of slow solar wind resided a…
Electron temperature of Titan's sunlit ionosphere
Coates, A. J.; Wahlund, J. -E.; Galand, M. +2 more
Titan's upper atmosphere is ionized by solar radiation and particle bombardment from Saturn's magnetosphere. The induced ionosphere plays a key role in the coupling of Titan's atmosphere with the Kronian environment. It also provides unique signatures for identifying energy sources upon Titan's upper atmosphere. Here we focus on observations from …
Low-energy (order 10 eV) ion flow in the magnetotail lobes inferred from spacecraft wake observations
Dandouras, I.; André, M.; Quinn, J. +4 more
Cold ionospheric ions with eV energies are common in the magnetosphere and can travel far out in the magnetotail. However, they are difficult to measure with conventional ion spectrometers mounted on spacecraft, since the potential of a sunlit spacecraft often reaches several tens of volts. In this paper we present two alternative methods of measu…
Cassini observations of planetary-period oscillations of Saturn's magnetopause
André, N.; Lewis, G. R.; Coates, A. J. +8 more
Examination of Cassini magnetic field and plasma data in the outer boundary regions of Saturn's magnetosphere shows that magnetopause oscillations at the planetary period commonly occur, in phase with plasma pressure variations inside the magnetosphere. The peak-to-trough amplitude of the boundary oscillations mapped to the planet-Sun line is esti…
Solar control of radar wave absorption by the Martian ionosphere
Gurnett, D. A.; Morgan, D. D.; Plaut, J. J. +6 more
The MARSIS active sounder aboard the Mars Express spacecraft, under certain conditions in the Martian ionosphere, fails to detect the planetary surface. We have generated a statistical measure of the surface reflection visibility, which we plot as a time series and compare with both in situ particle data taken at Mars and solar x-ray data taken at…
Hydrogen exosphere at Mars: Pickup protons and their acceleration at the bow shock
Barabash, S.; Lundin, R.; Yamauchi, M. +3 more
Pickup protons (PIs) with a ring-beam distribution originating from the extended hydrogen exosphere of Mars are observed by the ASPERA-3 experiment onboard the Mars Express spacecraft at solar minimum conditions. PIs can contribute ~1% to the solar wind number density at close distances to the flank bow shock. The observed fluxes of PIs indicate t…
Substorm associated magnetotail energetic electrons pitch angle evolutions and flow reversals: Cluster observation
Lucek, E.; Fritz, T. A.; Wu, P. +1 more
The Cluster satellites observed a distinct pattern in the evolution of energetic electron pitch angle distributions on November 13, 2003, in the mid-tail (radius >10RE) associated with intensifications of these electron fluxes that accompanied an observed local dipolarization of the magnetic field. The intensity of electrons (20-200 …
Dust devils on Mars observed by the High Resolution Stereo Camera
Greeley, Ronald; Pätzold, Martin; Neukum, Gerhard +2 more
Fourteen active dust devils were observed by the High Resolution Stereo Camera (HRSC) on Mars Express, which enable the first analysis of the forward speed of dust devils on Mars determined from orbit. Results show speeds on the order of 20 m/s, which compares favorably with values of the wind profiles estimated from the Martian Climate Database f…