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Dynamical and magnetic field time constants for Titan's ionosphere: Empirical estimates and comparisons with Venus
Luhmann, J. G.; Wahlund, J. -E.; Ågren, K. +12 more
Plasma in Titan's ionosphere flows in response to forcing from thermal pressure gradients, magnetic forces, gravity, and ion-neutral collisions. This paper takes an empirical approach to the ionospheric dynamics by using data from Cassini instruments to estimate pressures, flow speeds, and time constants on the dayside and nightside. The plasma fl…
Asymmetry of solar polar fields and the southward shift of HCS observed by Ulysses
Mursula, K.; Virtanen, I. I.
We study the hemispheric asymmetry of high-latitude unipolar fields and the latitudinal shift of the heliospheric current sheet (HCS) using Ulysses magnetic field observations during the perihelion passes in 1994-1995, 2001-2002, and 2007. Using the cumulative flux density and the best fit lines to its high-latitude observations in the two hemisph…
Global magnetohydrodynamic simulation of reconnection and turbulence in the plasma sheet
Goldstein, Melvyn L.; El-Alaoui, Mostafa; Walker, Raymond J. +3 more
Plasma sheet turbulence is examined by using a global MHD simulation. The simulation used idealized purely southward interplanetary magnetic field (IMF) driving conditions to eliminate the effect of solar wind and IMF variations. The results were compared with spacecraft observations of turbulence by computing power spectral densities and probabil…
The 3-D extent of the Io UV footprint on Jupiter
Bonfond, B.
The Io footprint (IFP) is the auroral signature of the electromagnetic interaction between Io and Jupiter's magnetosphere. It consists of several spots followed by an extended tail, which are located close to the feet of the magnetic field lines connecting Io to Jupiter. The size of the main spot is a controversial issue, and previously published …
Comparative analysis and variability of the Jovian X-ray spectra detected by the Chandra and XMM-Newton observatories
Bhardwaj, Anil; Branduardi-Raymont, Graziella; Lisse, Carey M. +6 more
Expanding upon recent work, a more comprehensive spectral model based on charge exchange induced X-ray emission by ions precipitating into the Jovian atmosphere is used to provide new understanding of the polar auroras. In conjunction with the Xspec spectral fitting software, the model is applied to analyze observations from both Chandra and XMM-N…
Pickup hydrogen distributions in the solar wind at ∼11 AU: Do we understand pickup ions in the outer heliosphere?
McComas, D. J.; Schwadron, N. A.; Elliott, H. A.
This study examines the detailed distribution of interstellar pickup hydrogen ions measured by the Surface Wave Process Program instrument on the New Horizons spacecraft en route to Pluto. The observations cover an 8 h interval on 15 October 2008 when the craft was at ∼11.3 AU, constituting the first detailed pickup ion measurements in the outer h…
Cassini INMS observations of neutral molecules in Saturn's E-ring
McNutt, Ralph L.; Mitchell, Donald G.; Waite, J. Hunter +6 more
In 2008, the Cassini ion neutral mass spectrometer (INMS) investigation made in situ measurements of neutral species near Saturn's equatorial plane within 0.5 Saturn radii (RS) of the orbit of Enceladus. After removing the large background and modeling to interpret instrumental effects, the data provide rough constraints on the neutral …
Observation of the multifractal spectrum in solar wind turbulence by Ulysses at high latitudes
Wawrzaszek, Anna; Macek, Wieslaw M.
The aim of our study is to examine the question of multifractal scaling properties of turbulence in the solar wind at high latitudes. We analyze time series of the velocities of the solar wind during solar minimum (1994-1997, 2006-2007) at various heliographic latitudes measured in situ by Ulysses, which is the only mission that has investigated p…
Test of methods to infer the magnetic reconnection geometry from spacecraft data
Baumjohann, W.; Hesse, M.; Birn, J. +5 more
When analyzing data from a cluster of spacecraft (such as Cluster or MMS) crossing a site of magnetic reconnection, it is desirable to be able to determine the orientation of the reconnection site. If the reconnection is quasi-two dimensional, there are three key directions, the direction of inhomogeneity (direction across the reconnection site), …
Nature of the ring current in Saturn's dayside magnetosphere
Persoon, A. M.; Coates, A. J.; Dougherty, M. K. +6 more
We employ magnetic field and plasma particle data from two equatorial passes of the Cassini spacecraft spanning the radial range between ∼3 and ∼20 RS to investigate the nature of the ring current in Saturn's dayside magnetosphere (RS is Saturn's equatorial radius, equal to 60,268 km). We examine plasma parameters obtained by…