Search Publications
Interstellar pickup ions and quasi-perpendicular shocks: Implications for the termination shock and interplanetary shocks
Zank, G. P.; Webb, G. M.; Pauls, H. L. +1 more
A new mechanism for the acceleration of pickup ions by repeated reflections from the electrostatic cross shock potential of a quasi-perpendicular shock is presented. The acceleration mechanism, multiply reflected ion (MRI) acceleration, offers a resolution to the issue of injecting pickup ions into an efficient particle energization scheme, and th…
Motion of the footpoints of heliospheric magnetic field lines at the Sun: Implications for recurrent energetic particle events at high heliographic latitudes
Fisk, L. A.
The interplay between the differential rotation of the footpoints of heliospheric magnetic field lines in the photosphere and the subsequent nonradial expansion of these same field lines with the solar wind from rigidly rotating coronal holes can result in extensive excursions of heliospheric magnetic field lines with heliographic latitude. Thus m…
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…
Recent results on the parameters of the interstellar helium from the ULYSSES/GAS experiment
Rosenbauer, H.; Witte, M.; Banaszkiewicz, M.
Velocity and direction of the flow of the interstellar helium and its temperature and density have been determined from the measurements of the ULYSSES/GAS experiment for two different epochs: during the in-ecliptic path of ULYSSES, representing solar maximum conditions, and during the south to the north pole transition (11/94-6/95), close to the …
Corotating and Transient Solar Wind Flows in Three Dimensions
Gosling, J. T.
Two types of flows dominate the large-scale structure of the solar wind: corotating flows and transient disturbances. Corotating flows are associated with spatial variability in the coronal expansion and solar rotation, whereas transient disturbances are associated with episodic ejections of material into interplanetary space from coronal regions …
ULYSSES plasma parameters: latitudinal, radial, and temporal variations.
Goldstein, B. E.; Neugebauer, M.; Phillips, J. L. +6 more
Observations by the Ulysses SWOOPS plasma experiment are used to investigate spatial and temporal gradients during the mission, with emphasis on more recent high latitude observations including the recent South Pole to North Pole passage during solar minimum. Compared to lower latitudes, the high latitude solar wind had higher average speed, proto…
Statistical acceleration of interstellar pick-up ions in co-rotating interaction regions
Schwadron, N. A.; Gloeckler, G.; Fisk, L. A.
Observations from the SWICS instrument on Ulysses reveal that there is little evidence for the acceleration of interstellar pick-up ions at the forward and reverse shocks which surround Co-rotating Interactions Regions (CIR's) in the solar wind. Rather, the pick-up ions exhibit strong acceleration in regions within the CIR where there are increase…
Abundance of 3He in the local interstellar cloud
Gloeckler, George; Geiss, Johannes
THE primordial abundances of the light elements and their isotopes provide essential information regarding the nucleosynthetic processes that occurred in the Big Bang1,2. At present the best estimates of the baryon/photon ratio of the Universe, a fundamental cosmological parameter, are extrapolations to primordial times of light-element…
A Solar Polar North-South Asymmetry for Cosmic-Ray Propagation in the Heliosphere: The ULYSSES Pole-to-Pole Rapid Transit
Simpson, J. A.; Bame, S.; Zhang, Ming
The pole-to-pole fast transit of the heliosphere at ~2 AU from the Sun by the international Ulysses spacecraft has made it possible for the first time to investigate in three dimensions the solar wind, interplanetary magnetic field, and---as reported herein---the global propagation of Galactic cosmic rays and anomalous helium. We use measurements …
The heliospheric magnetic field at solar minimum: ULYSSES observations from pole to pole.
Balogh, A.; Horbury, T. S.; Forsyth, R. J. +3 more
The fast transit of the Ulysses spacecraft from the south polar regions of the heliosphere to the north polar regions has allowed us to obtain a unique perspective on the configuration and properties of the heliospheric magnetic field at a time of solar minimum activity. We compare the magnetic field in the northern and southern hemispheres and fi…