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Alfvén waves, alpha particles, and pickup ions in the solar wind
Smith, E. J.; Goldstein, B. E.; Neugebauer, M.
Past studies of the properties of Alfvén waves in the solar wind have indicated that (1) the amplitude of the velocity fluctuations is almost always smaller than expected on the basis of the amplitude of the field fluctuations, even when the anisotropy of the plasma is taken into account, and (2) the alpha particles often do not participate in the…
Variation of fractional electron density fluctuations inside 40 Ro observed by Ulysses ranging measurements
Bird, M. K.; Woo, Richard; Armstrong, J. W. +1 more
The first measurements of fractional electron density fluctuations δne/ne, where δne is rms electron density fluctuation and ne is the mean electron density, have been carried out inside 40 Ro using 1991 Ulysses dual-frequency S- and X-band (13 and 3.6 cm) ranging (time delay) measurements. In…
Results of the Ulysses fast latitude scan: Magnetic field observations
Balogh, A.; Forsyth, R. J.; Burton, M. E. +2 more
The rapid crossing of the solar equatorial region by Ulysses as it returned from the south pole resulted in 7 crossings of the heliospheric current sheet between 10°S and 20°N and 10 distinct solar wind interaction regions between 18°S and 22°N. Both the extent of the current sheet and the latitude interval containing the interaction regions are a…
Observations of evolving turbulence in the polar solar wind
Balogh, A.; Horbury, T. S.; Forsyth, R. J. +1 more
The Ulysses magnetic field experiment has measured the heliospheric magnetic field in solar wind flows from the Sun's Southern polar coronal hole over a wide range of heliolatitudes and distances. We present an analysis of more than one year of data, covering a latitude range of 40° to 80°S and a distance range of 4.0 to 1.7 AU. We extend an earli…
The underlying magnetic field direction in Ulysses observations of the southern polar heliosphere
Balogh, A.; McComas, D. J.; Forsyth, R. J. +2 more
Between April and November 1994 the Ulysses spacecraft explored heliographic latitudes above 60°S in the southern polar heliosphere and had returned to 20°S by February 1995. We have used hourly averages of the magnetic field measurements made by Ulysses to study the underlying heliospheric field direction. In contrast to data previously reported …
The Ulysses south polar pass: Energetic ion observations
Balogh, A.; Forsyth, R. J.; Goldstein, B. E. +5 more
We present here a preliminary analysis of observations of energetic ions during the first polar pass of the Ulysses spacecraft, concentrating mainly on the region where the spacecraft was continually immersed in high speed flow from the polar coronal hole. During the ascent to high latitudes, a single recurrent peak was observed once per solar rot…
Observations of plasma waves in magnetic holes
Pick, M.; Balogh, A.; Forsyth, R. J. +5 more
We report the first observations of Langmuir waves excited within magnetic holes, which are characterized by a depression of magnetic field strength. This phenomenon is very common in the solar wind. In addition to Langmuir waves, waves at a few kHz, which are typical of Doppler-shifted ion acoustic frequencies in the solar wind, and low frequency…
Anisotropy of inertial range turbulence in the polar heliosphere
Balogh, A.; Horbury, T. S.; Forsyth, R. J. +1 more
A variance analysis of high frequency, inertial range fluctuations in the polar magnetic field as recorded by the Ulysses spacecraft indicates that they are largely transverse to the ambient magnetic field direction and highly anisotropic. Despite large changes in the mean field direction caused by the presence of large amplitude Alfvén waves, ali…
Simultaneous observations of the Saturnian aurora and polar haze with the HST/FOC
Waite, J. H.; Grodent, D.; Gladstone, G. R. +3 more
Near simultaneous observations of the Saturnian H2 north ultraviolet aurora and the polar haze were made at 153 nm and 210 nm respectively with the Faint Object Camera on board the post-COSTAR Hubble Space Telescope. The auroral observations cover a complete rotation of the planet and, when co-added, they reveal the presence of an auror…
The latitude gradients of galactic cosmic ray and anomalous helium fluxes measured on Ulysses from the Sun's south polar region to the equator
Simpson, J. A.; McKibben, R. B.; Zhang, M. +2 more
Measurements from the Ulysses COSPIN (Cosmic Ray and Solar Particle INvestigations) High Energy Telescope between 80.2°S solar latitude and the sun's equator from September 1994 to March 1995 confirm that the modulated fluxes of galactic cosmic rays and anomalous components depend only weakly on heliographic latitude in the inner heliosphere at th…