Search Publications
Composition of quasi-stationary solar wind flows from Ulysses/Solar Wind Ion Composition Spectrometer
Geiss, J.; Wimmer-Schweingruber, R. F.; Schwadron, N. A. +6 more
Using improved, self-consistent analysis techniques, we determine the average solar wind charge state and elemental composition of nearly 40 ion species of He, C, N, O, Ne, Mg, Si, S, and Fe observed with the Solar Wind Ion Composition Spectrometer on Ulysses. We compare results obtained during selected time periods, including both slow solar wind…
Solar wind observations over Ulysses' first full polar orbit
Balogh, A.; McComas, D. J.; Goldstein, B. E. +7 more
This study examines solar wind plasma and magnetic field observations from Ulysses' first full polar orbit in order to characterize the high-latitude solar wind under conditions of decreasing and low solar activity. By comparing observations taken over nearly all heliolatitudes and two different intervals covering the same radial distances, we are…
Rigidity dependence of cosmic ray proton latitudinal gradients measured by the Ulysses spacecraft: Implications for the diffusion tensor
Potgieter, M. S.; Heber, B.; Burger, R. A.
The latitudinal gradient of cosmic ray protons observed by Ulysses during September 1994 to July 1995 is small, and it increases as function of rigidity up to ~2 GV and then decreases. Although previous drift models could reproduce the observed small positive gradient for an A>0 solar polarity cycle, they produced a maximum at a rigidity well b…
Aspects of the mass distribution of interstellar dust grains in the solar system from in situ measurements
Krüger, H.; Grün, E.; Landgraf, M. +2 more
The in situ detection of interstellar dust grains in the solar system by the dust instruments on-board the Ulysses and Galileo spacecraft as well as the recent measurements of hyperbolic radar meteors give information on the properties of the interstellar solid particle population in the solar vicinity. Especially the distribution of grain masses …
A global MHD solar wind model with WKB Alfvén waves: Comparison with Ulysses data
Goldstein, Melvyn L.; Usmanov, Arcadi V.; Besser, Bruno P. +1 more
We use a steady state global axisymmetric MHD model to reproduce quantitatively the Ulysses observations during its first fast latitude traversal in 1994-1995. In particular, we are able to account for the transformation of a surface dipole magnetic field near the Sun into the configuration observed at large heliocentric distances. The MHD equatio…
Variations of Saturn's radio rotation period measured at kilometer wavelengths
Lecacheux, Alain; Galopeau, Patrick H. M.
The Unified Radio and Plasma Wave (URAP) experiment on the interplanetary spacecraft Ulysses is able to detect the Saturnian kilometric radiation (SKR) thanks to the high sensitivity of the receiver and in spite of the remoteness of the planet (8-13 AU). Our knowledge about Saturn comes essentially from the observations by the two Voyager spacecra…
On the evolution of outward and inward Alfvénic fluctuations in the polar wind
Bavassano, B.; Pietropaolo, E.; Bruno, R.
Plasma and magnetic field measurements by Ulysses are used to investigate the radial evolution of hourly-scale Alfvénic fluctuations in the polar wind. The data span from 1.4 to 4.3 AU in heliocentric distance. Different radial regimes at different distances emerge. Inside about 2.5 AU the large outward traveling fluctuations decrease faster, in t…
Solar wind electron suprathermal strength and temperature gradients: Ulysses observations
Maksimovic, Milan; Gary, S. Peter; Skoug, Ruth M.
We use observations from the Ulysses electron spectrometer to examine global trends of the electron suprathermal population and to study, for the first time, the electron core, halo, and total temperature gradients in the fast solar wind over the poles. We use a data set covering the period from the beginning of the mission (1990, day of year 322)…
Modeling the motion and distribution of interstellar dust inside the heliosphere
Landgraf, M.
The interaction of dust grains originating from the local interstellar cloud with the environment inside the heliosphere is investigated. As a consequence of this interaction, the spatial distribution of interstellar dust grains changes with time. Since dust grains are charged in the interplanetary plasma and radiation environment, the interaction…
Elemental composition of the inner source pickup ions
Geiss, J.; Schwadron, N. A.; Zurbuchen, T. H. +2 more
Observations of the composition of inner source pickup ions in the solar wind, from the Solar Wind Ion Composition Spectrometer on Ulysses, are presented. The composition is similar to that of the solar wind and, in particular, contains volatile elements such as neon. These observations suggest strongly, and perhaps conclusively, that inner source…