Search Publications
Ulysses electron distributions fitted with Kappa functions
Maksimovic, Milan; Riley, Pete; Pierrard, Viviane
We fit Kappa functions to 16,000 velocity distribution functions measured in the solar wind by the electron plasma instrument on board Ulysses. Statistically, the electron distributions are observed to have important high velocity tails in the fast solar wind but are closer to a Maxwellian in the slow wind. We also discuss how this result could su…
SWICS/Ulysses observations: The three-dimensional structure of the heliosphere in the declining/minimum phase of the solar cycle
Livi, S.; Woch, J.; Geiss, J. +5 more
The ESA/NASA spacecraft Ulysses provides the first in-situ observation of the solar wind at high solar latitudes. Data obtained with the Solar Wind Ion Composition Spectrometer (SWICS) during the first orbit of Ulysses around the Sun can be used to obtain a global view of the solar wind pattern within the heliosphere during the declining/minimum p…
Extension of coronal structure into interplanetary space
Habbal, Shadia Rifai; Woo, Richard
We investigate the extension and evolution of the solar corona into interplanetary space by comparing 1995 Ulysses radio occultation measurements of path-integrated electron density and density fluctuations measured between 21 and 32 Ro, with simultaneous white-light measurements made by the HAO Mauna Loa K-coronameter below 2.5 Ro…
Detection of SO2 on Callisto with the Hubble Space Telescope
Johnson, Robert E.; McGrath, Melissa A.; Noll, Keith S. +1 more
We have detected SO2 in ultraviolet spectra of Callisto obtained with the Hubble Space Telescope's Faint Object Spectrograph. An absorption band centered at 280 nm appears in the spectrum of Callisto's leading hemisphere, but is not apparent in the spectrum of the trailing hemisphere. The band is similar to the SO2 band on Eu…
The Pele Plume (Io): Observations with the Hubble Space Telescope
Ballester, Gilda E.; McGrath, Melissa A.; Spencer, John R. +3 more
In July 1996, with the Hubble Space Telescope (HST), we observed the Pele plume silhouetted against Jupiter at a wavelength of 0.27µm, the first definitive observation of an Io plume from Earth. The height, 420 ± 40 km, was greater than any plume observed by Voyager. The plume had significantly smaller optical depth at 0.34 and 0.41µm, where it wa…
The northern edge of the band of solar wind variability: Ulysses at ∼4.5 AU
McComas, D. J.; Goldstein, B. E.; Bame, S. J. +4 more
Ulysses observations reveal that the northern edge of the low-latitude band of solar wind variability at ∼4.5 AU was located at N30° in the latter part of 1996 when solar activity was at a minimum. This edge latitude is intermediate between edge latitudes found during previous encounters with the band edge along different portions of Ulysses' pola…
Venus tail ray observation near Earth
Livi, S.; Hsieh, K. C.; Wurz, P. +23 more
In June, 1996, Venus passed through a very close inferior conjunction with the Sun. At that time the CTOF detector of the CELIAS mass spectrometer experiment on the SOHO spacecraft near Earth's L1 Lagrangian point was measuring heavy ions in the solar wind ∼4.5 × 107 km downstream of Venus. Close to the time predicted by simple geometri…
Ulysses observations of the northward extension of the heliospheric current sheet
Balogh, A.; Forsyth, R. J.; Smith, E. J. +1 more
After passing through the northern polar regions of the heliosphere during the summer of 1995, the Ulysses spacecraft has been gradually returning towards lower equatorial latitudes, reaching 30°N in August 1996 at about which time low speed solar wind from the streamer belt was once again observed. This paper reports on the Ulysses magnetic field…
Is the geoeffectiveness of the 6 January 1997 CME predictable from solar observations?
Hoeksema, J. T.; Zhao, X. P.
We present a prediction scheme for specifying the duration and maximum strength of the southward IMF within a magnetic cloud from observations of the disappearing filament associated with the coronal mass ejection and the photospheric magnetic field made near the filament disappearing. Using this scheme we were able to predict that the Earth direc…
Particle acceleration at corotating reverse shocks in the southern hemisphere: Ulysses results
Balogh, A.; Forsyth, R. J.; Desai, M. I. +3 more
We have correlated the ∼1 MeV proton intensity (J) measured at corotating reverse shocks detected by Ulysses in the southern hemisphere with two parameters that characterise the strength of the shock. Between 6°-29°S J is essentially independent of the shock strength, whereas between 29°-41°S J is well correlated with the same. The poor correlatio…