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D/H and O-18/O-16 ratio in the hydronium ion and in neutral water from in situ ion measurements in comet Halley
Altwegg, K.; Balsiger, H.; Geiss, J.
The D/H ratio and the O-18/O-16 ratio in hydronium ions in the gas coma of comet Halley have been determined from ion data obtained by the high intensity sensor (HIS) of the ion spectometer (IMS) on board the spacecraft Giotto in 1986. The HIS instrument measured the reliable data for the water group ions over a large distance range from the nucle…
Ulysses observations of microstreams in the solar wind from coronal holes
Balogh, A.; McComas, D. J.; Goldstein, B. E. +2 more
During its south polar passage in 1994, the Ulysses spacecraft continuously sampled the properties of the solar wind emanating from the south polar coronal hole. At latitudes poleward of ~-60°, the solar wind speed had an average value of 764 km/s and a range of 700-833 km/s. The principal variations in the vector velocity were associated with eit…
Ulysses observation of a noncoronal mass ejection flux rope: Evidence of interplanetary magnetic reconnection
Balogh, A.; McComas, D. J.; Forsyth, R. J. +5 more
A well-defined, small-scale (~0.05 AU) magnetic flux rope was observed by Ulysses at about 5 AU in close proximity to a heat flux dropout (HFD) at the heliospheric current sheet (HCS). This magnetic flux rope is characterized by a rotation of the field in the plane approximately perpendicular to the ecliptic (and containing the Sun and the spacecr…
C+ pickup ions in the heliosphere and their origin
Geiss, J.; Gloeckler, G.; Fisk, L. A. +1 more
C+ pickup ions were discovered with the solar wind ion composition spectrometer flying on Ulysses. Whereas the other nonlocally occurring pickup ions are produced from the interstellar gas penetrating deep into the heliosphere, C+ comes from an ``inner source'' which is located at a solar distance of a few AU and extends over…
The albedo spectrum of Europa from 2200 Å to 3300 Å
Weaver, H. A.; Noll, Keith S.; Gonnella, A. M.
We obtained a spectrum of Europa from 2224 to 3302 Å with high signal to noise and a resolution of 6.3 Å with the Hubble space telescope faint object spectrograph. We detect a broad absorption feature centered at 2800 Å, seen previously at lower signal to noise in International Ultraviolet Explorer spectra of Europa. No additional absorption featu…
Intermittent turbulence in solar wind from the south polar hole
Balogh, A.; Smith, E. J.; Goldstein, B. E. +2 more
The magnetic fields measured by the Ulysses spacecraft are used to study solar wind turbulence in the fast solar wind from the south polar hole. The spacecraft was at about 46 deg south latitude and 3.9 AU. For a magnetic field with a Gaussian distribution the power spectrum (second-order structure function) is sufficient to completely characteriz…
Structures in the polar solar wind: Plasma and field observations from Ulysses
Balogh, A.; McComas, D. J.; Forsyth, R. J. +5 more
Ulysses has frequently observed solar wind structures lasting from several hours to several days since it passed into the region of solar wind emanating from the southern polar coronal hole at ~36°S. In addition to previously reported Alfven waves and coronal mass ejections, two other sorts of structures are routinely evident. This paper provides …
Solar wind electron parameters from quasi-thermal noise spectroscopy and comparison with other measurements on Ulysses
Maksimovic, M.; Phillips, J. L.; Canu, P. +4 more
Plasma thermal noise spectroscopy was used for the first time on a large scale on the Ulysses radio receiver data to measure the solar wind electron density and temperature in the ecliptic plane. The validity and limitations of the results obtained with this method are discussed. nearly simultaneous measurements of the electron density and tempera…
Dispersion of electrostatic waves in the Io plasma torus and derived electron temperature
Moncuquet, M.; Meyer-Vernet, N.; Hoang, S.
We present a detailed analysis of the set of radio spectra acquired during the Ulysses spacecraft passage through the outer part of the Io plasma torus (at ~8 RJ). Since Ulysses is the first spacecraft to explore the torus far from the equator and the onboard plasma analyzers were shut off, these wave data are the only ones providing an…
Flow downstream of the heliospheric terminal shock: Magnetic field line topology and solar cycle imprint
Suess, S. T.; Nerney, Steven; Schmahl, E. J.
The topology of the magnetic field in the heliosheath is illustrated using plots of the field lines. It is shown that the Archimedean spiral inside the terminal shock is rotated back in the heliosheath into nested spirals that are advected in the direction of the interstellar wind. The 22-year solar magnetic cycle is imprinted onto these field lin…