Search Publications
Evidence for an Io plasma torus influence on high-latitude Jovian radio emission
Brown, M. E.; Kaiser, M. L.; Desch, M. D.
We report the discovery with the Ulysses unified radio and plasma wave (URAP) instrument of features in the Jovian hectometer (HOM) wavelength radio emission spectrum which recur with a period about 2-4% longer than the Jovian System III rotation period. We conclude that the auroral HOM emissions are periodically blocked from ``view'' by regions i…
Three-dimensional multiscale MHD model of cometary plasma environments
Gombosi, Tamas I.; De Zeeuw, Darren L.; Häberli, Roman M. +1 more
First results of a three-dimensional multiscale MHD model of the interaction of an expanding cometary atmosphere with the magnetized solar wind are presented. The model starts with a supersonic and super-Alfvènic solar wind far upstream of the comet (25 Gm upstream of the nucleus) with arbitrary interplanetary magnetic field orientation. The solar…
A large polar crown coronal mass ejection and a ``problem'' geomagnetic storm: April 14-23, 1994
Dryer, M.; Weiss, L.; Singer, H. +2 more
In the 1960s and 1970s, systematic programs to associate geomagnetic storms with solar flares gave rise to a category of ``problem storms'' for which there were no clear associations or for which the associations were with solar activity that seemed too insignificant to properly account for the magnitude of the geomagnetic events. In the last 2 de…
Ulysses observations of differential alpha-proton streaming in the solar wind
Smith, E. J.; Goldstein, B. E.; Neugebauer, M. +1 more
Data from the solar wind spectrometer on the Ulysses spacecraft are used to study the differential streaming between the alpha particles and protons in the solar wind over the heliographic distance range of 1.3 to 5.4 AU and latitudes from 0° to +/-80° during the period December 1990 through September 1995. The study is based on 6-hour averages of…
Statistical properties of mirror mode structures observed by Ulysses in the magnetosheath of Jupiter
Balogh, A.; Erdős, G.
During the outbound pass of the Jovian magnetosheath in February 1992, a large number of magnetic depressions, without a significant change in the direction of the magnetic field vector, were observed by the Ulysses magnetometer. These low-frequency fluctuations, identified earlier as mirror mode waves, lasted about 1 day. The largest amplitude fl…
Interaction of a nonuniform solar wind with the local interstellar medium
Zank, G. P.; Pauls, H. L.
Results from a fully time dependent three-dimensional gasdynamic model of the interaction of the solar wind with the local interstellar medium are presented. Both subsonic and supersonic interstellar winds are considered, while the mediating effects of interstellar neutrals, magnetic fields, and cosmic rays are ignored. In accord with solar minimu…
Wavelength and direction filtering by magnetic measurements at satellite arrays: Generalized minimum variance analysis
Glassmeier, K. H.; Motschmann, U.; Southwood, D. J. +2 more
The main goal of the Cluster mission, consisting of four identical spacecraft, is the spatial resolution of plasma structures. For the determination of the wave vectors of a wave field from four positions, classical Fourier analysis is inappropriate. We develop a generalized minimum variance technique which gives a high wave vector resolution thou…
Volumetric heating in coronal streamers
Wu, S. T.; Suess, S. T.; Wang, A. -H.
The addition of a volumetric heat source to a coronal streamer model produces distinct, important changes in the model. Originally, such heating was added to meet the observational requirement for a thin current sheet above streamers. Here we report additional consequences of a volumetric heat source, together with the effects of redistribution of…
Interplanetary discontinuities and Alfvén waves at high heliographic latitudes: Ulysses
Balogh, A.; Goldstein, B. E.; Neugebauer, M. +5 more
This paper presents the results of the first statistical study of interplanetary directional discontinuities at both low and high heliographic latitudes measured by the Ulysses magnetometer. There is a gradual decrease in the rate of occurrence of interplanetary discontinuities (ROIDs) with increasing radial distance. From 1 to 5 AU, an e-(r-…
The underlying Parker spiral structure in the Ulysses magnetic field observations, 1990-1994
Balogh, A.; McComas, D. J.; Forsyth, R. J. +2 more
The fundamental aim of the Ulysses space mission is to extend our understanding of the heliosphere into three dimensions. By April 1994 the spacecraft had reached a heliographic latitude of 60°S. Hourly averages of the Ulysses heliospheric magnetic field observations have been analyzed to determine to what extent the underlying field direction wit…