Search Publications
Abundance variations in the solar wind
Geiss, J.; Gloeckler, G.; von Steiger, R. +1 more
The solar wind (SW) allows us to probe the solar material in situ, particularly its composition, without the need to fly a spacecraft to inhospitably small heliocentric distances. However, it turns out that this plasma source is biased with respect to the photosphere. Elements with a low first ionization potential (FIP) are overabundant by a facto…
ULYSSES observations of latitude gradients in the heliospheric magnetic field
Phillips, J.; Balogh, A.; Tsurutani, B. T. +3 more
Several parameters measured by Ulysses as it traveled southward to heliographic latitudes of -50 deg are presented and analyzed. The radial component of the magnetic field, averaged over 5 deg latitude increments and extrapolated back to 1 AU, is found to agree with baseline measurements provided by IMP-8. There is little, if any, evidence of a la…
ULYSSES solar wind plasma observations during the declining phase of solar cycle 22
McComas, D. J.; Goldstein, B. E.; Bame, S. J. +5 more
Since launch in October 1990, the Ulysses mission has included an in-ecliptic cruise enroute to Jupiter encounter in February 1992 and a post-Jupiter transit through a wide range of southerly latitudes and heliocentric distances. Here we present results from the solar wind plasma experiment through June 14, 1994, at which time Ulysses was at -68.2…
Solar wind plasma electron parameters based on aligned observations by ICE and ULYSSES
Scime, E. E.; Phillips, J. L.; Gosling, J. T. +1 more
During November-December 1991, the International Cometary Explorer and Ulysses spacecraft were aligned in solar longitude, with an angular offset as small as 1 deg and a radial offset of 3.8 to 4.0 AU. Both spacecraft carry spectrometers which measure the thermal and suprathermal solar wind electron distributions. During the alignment interval, bo…
Cometary ion pickup processes: Halley and Grigg-Skjellerup compared
Johnstone, A. D.
After Giotto's encounters with two comets of quite different gas production rates we attempt to compare the results to see:- a) to what extent theories which fitted the results at Halley could be applied to the much smaller Grigg-Skjellerup; b) whether the different relationship between the various scale lengths involved created any observable eff…
The anomalous nuclear component in the three-dimensional heliosphere
Simpson, J. A.
The anomalous nuclear component is neither of solar nor galactic cosmic ray origin. Its presence in the heliosphere is an independent probe for both interplanetary electrodynamical investigations--especially solar modulation--and probably the most direct means for determining the elemental and isotopic composition of those neutral atoms in the loc…
Comparison of the main magnetic and plasma features in the environments of comets Grigg-Skjellerup and Halley
Glassmeier, K. -H.; Neubauer, F. M.; Reme, H. +1 more
The successful flyby of Giotto at the weakly active comet P/Grigg-Skjellerup on July 10, 1992 has added a new set of observations to those obtained at the active comet P/Halley in March 1986 for the study of the solar wind - comet interaction. Despite the very different scales of the interaction regions for the two comets (10^6 km for Halley and 1…
Interplanetary shocks observed by ULYSSES in the ecliptic plane as a function of the heliocentric distance
Balogh, A.; Pantellini, F.; Forsyth, R. J. +5 more
During its mission in the ecliptic plane, the Ulysses spacecraft crossed many heliospheric large-scale structures. Several interplanetary (IP) shocks were identified and characterized using the radio receiver, magnetometer and proton analyser aboard. The spectroscopy of the thermal noise measured by the radio receiver gives the plasma electron den…
HST UV observations of the accretion disk corona X-ray binary X1822-371
Mason, K. O.; Cordova, F. A.; Puchnarewicz, E. M.
The Faint Object Spectrograph on the Hubble Space Telescope has provided the first ultraviolet orbital light curve of the low-mass X-ray binary X1822-371. The shape of the UV light curve changes with wavelength providing the first direct clues to the temperature of the various system components. The data support the idea that the system contains a…
Magnetic observations during the recent declining phase of solar activity
Smith, E. J.
Changes in the heliospheric magnetic field during the recent declining phase in solar activity are reviewed and compared with observations during past sunspot cycles. The study is based principally on data obtained by IMP-8 and Ulysses. The field magnitude is found to have increased during the declining phase until it reached a maximum value of 11…