Search Publications
Origins of Anisotropic 40 300 keV Electron Events Observed at Low and High Latitudes
Pick, M.; Gold, R. E.; Hawkins, S. E., III +1 more
Using a survey of anisotropic electron events in the energy range of ∼40 300 keV observed by HI-SCALE on Ulysses, we have selected several time intervals during 1999 when Ulysses traveled from about 20° S at 5.2 AU (January 1999) to 42° S at 4.2 AU (January 2000). We compare these events with observations at ∼1 AU using the nearly identical instru…
Oxygen and Iron Ions at High Heliolatitudes
Lanzerotti, L. J.; Gold, R. E.; Maclennan, C. G.
The fluxes of O and Fe ions at high heliolatitudes measured by the HiScale instrument on Ulysses reflect the dynamical processes that affect the charged particle populations in the heliosphere. Both the O and Fe ions show more latitude dependence in the first (solar minimum) orbit to high southern heliolatitudes than during the second (solar maxim…
Source Region of High and Low Speed Wind during the Spartan 201-05 Flight
Skoug, Ruth; Kucera, Therese; Fisher, Richard +4 more
The large-scale coronal magnetic fields of the Sun are believed to play an important role in organizing the coronal plasma and channeling the high and low speed solar wind along the open magnetic field lines of the polar coronal holes and the rapidly diverging field lines close to the current sheet regions, as has been observed by the instruments …
A Survey of Field-Aligned Mach Number and Plasma Beta in the Solar Wind
De Keyser, Johan; Poedts, Stefaan; Roth, Michel +1 more
We have surveyed solar wind plasma beta and field-aligned Alfvénic Mach number using Ulysses and Wind data. We show the characteristic timescale and occurrence frequency of `magnetically dominated' solar wind, whose interaction with a planetary magnetosphere may produce a bow shock with multiple shock fronts. We discuss radial, latitudinal, and so…
Associating the Solar Wind Measured by Ulysses with its Source at the sun
Habbal, Shadia Rifai; Woo, Richard
Radio occultation, ultraviolet, and white-light measurements have expanded our knowledge of the morphology of density and velocity in polar coronal holes, and made it possible to carry out the first systematic comparisons between the Ulysses solar wind measurements and quantitative white-light observations of the solar corona. This paper summarize…
Comparison of quiet-Sun radiances measured by CDS and SUMER on SOHO
Solanki, S. K.; Wilhelm, K.; Schühle, U. +6 more
Since the beginning of the SOHO (Solar and Heliospheric Observatory) mission an intercalibration programme was carried out which included simultaneous observations of the EUV instruments CDS (Coronal Diagnostic Spectrometer) and SUMER (Solar Ultraviolet Measurements of Emitted Radiation) of common targets on the quiet Sun. The observations in the …
Comparison of ≳40 keV Electron Events at High and Low Heliolatitudes: Ulysses/HI-SCALE and ACE/EPAM
Lario, D.; Roelof, E. C.; Ho, G. C. +2 more
We have performed a joint survey of anisotropic ≳40 keV electron events from August 1997 to September 2000 using the matched detectors on the Ulysses (ULS)/HI-SCALE and the ACE/EPAM instruments. A computer algorithm selected events with strong, statistically significant pitch-angle anisotropies. Electron pitch-angle distributions at ACE (∼1 AU) ar…
Survey of MeV proton anisotropies measured by Ulysses
Balogh, André; Dalla, Silvia
The Anisotropy Telescopes (ATs) instrument, part of the COSPIN experiment on board Ulysses, measures fluxes and anisotropies of protons in the MeV range. We survey data from this instrument throughout the Ulysses mission, with particular emphasis on solar maximum, when large particle intensities were measured. The only significant fluxes detected …
Coronal Heating and Solar Wind Acceleration: Future Work on Observations
Peter, Hardi
The space-based observatories SOHO and TRACE have shown some very interesting results on the structure and dynamics of the Sun and its atmosphere, e.g., the extremely high ion temperatures or the enormous variability in the corona. But one question is still open to debate: how to use these data to distinguish between different types of physical he…
Observations of the Acceleration of Polar Solar Wind Near Solar Maximum
Simnett, G. M.; Tappin, S. J.; Lyons, M. A.
In a previous paper (Tappin et al., 1999) we used cross-correlation analysis of high-cadence observations with the LASCO coronagraphs to trace the acceleration of the solar wind at low latitudes. In this paper we present a similar analysis carried out over the North pole of the Sun. The observations which were made in March 2000 with the C3 corona…