Search Publications
Latitudinal dependence of outflow velocities from O VI Doppler dimming observations during the Whole Sun Month
Kohl, John L.; Noci, Giancarlo; Gibson, Sarah E. +4 more
Empirical determinations of outflow velocities in the solar corona provide a much needed constraint, along with density and temperature determinations, of the acceleration and heating mechanisms in the extended corona. Much progress has been made on density determinations from white light polarized brightness observations but outflow velocities ha…
Modulation effects of anisotropic perpendicular diffusion on cosmic ray electron intensities in the heliosphere
Ferreira, S. E. S.; Potgieter, M. S.; Heber, B. +1 more
The modulation of cosmic ray electrons provides a useful tool to study the diffusion tensor applicable to heliospheric modulation. Electron modulation responds directly to the assumed energy dependence of the diffusion coefficients below ~500 MeV in contrast to protons which experience large adiabatic energy losses below this energy. As a result o…
Context and heliographic dependence of heliospheric planar magnetic structures
Balogh, A.; Jones, G. H.
An analysis is presented of planar magnetic structures (PMSs) detected in the solar wind by the Ulysses spacecraft between its launch in October 1990 and the end of 1998. In all, 667 such structures were found, with durations between 6 hours (the minimum in the search algorithm) and 66 hours. The total amount of magnetometer data found to represen…
Techniques for galactic dust measurements in the heliosphere
Krüger, Harald; Grün, Eberhard; Landgraf, Markus +5 more
Galactic interstellar dust (ISD) is the major ingredient in planetary formation. However, information on this important material has been extremely limited. Recently, the Ulysses dust detector has identified and measured interstellar dust outside 1.8 AU from the Sun at ecliptic latitudes above 50°. Inside this distance it could not reliably distin…
Wind-driven surface waves on Titan
Ghafoor, Nadeem A. -L.; Zarnecki, John C.; Challenor, Peter +1 more
The surface of Titan represents the largest surface area in the solar system essentially unexplored, although recent observations from Hubble Space Telescope and ground-based telescopes using adaptive optics have given perhaps the first low-resolution indications of its nature. Whilst early models citing global oceans have been all but abandoned, …
Energetic proton observations at 1 and 5 AU: 2. Rising phase of the solar cycle 23
Plunkett, S. P.; Lario, D.; Balogh, A. +7 more
The increasing level of solar activity at the end of 1997 coincides with the observation of solar energetic particle (SEP) events by the Wind and Ulysses spacecraft. The proximity of Ulysses to the ecliptic plane during this period allows us to study the effects of the solar activity at two different heliolongitudinal and heliocentric distances bu…
Model for the mass fractionation in the January 6, 1997, coronal mass ejection
Bochsler, Peter; Wurz, Peter; Lee, Martin A.
For the coronal mass ejection (CME) of January 6, 1997, strong element fractionation of the heavy ions was observed at 1 AU with the Mass Time-of-Flight (MTOF) sensor of the Charge, Element, and Isotope Analysis System (CELIAS) on the Solar and Heliospheric Observatory (SOHO). During the passage of the CME plasma and the passage of the erupted fil…
Oxygen freeze-in temperatures measured with SOHO/CELIAS/CTOF
Bochsler, P.; Grünwaldt, H.; Hefti, S. +1 more
We use the charge time-of-flight (CTOF) mass and charge spectrometer of the charge, element, and isotope analysis system (CELIAS) on board the Solar and Heliospheric Observatory (SOHO) to determine the solar wind oxygen freeze-in temperature T76 from the O7+ and O6+ abundance ratios in the period from days 92 to 22…
The May 1997 SOHO-Ulysses quadrature
Romoli, M.; Goldstein, B. E.; Neugebauer, M. +3 more
We present results from the May 1997 SOHO-Ulysses quadrature (SOHO-Sun-Ulysses angle=90°), near sunspot minimum. Ulysses was at 5.1 AU, 10° north of the solar equator, and off the east limb. It was also at the very northern edge of the streamer belt. Nevertheless, the Solar Wind Observations Over the Poles of the Sun instrument (SWOOPS) detected o…
Connecting the Sun and the solar wind: Source regions of the fast wind observed in interplanetary space
Habbal, Shadia Rifai; Woo, Richard
Highly sensitive radio occultation and white light measurements of path-integrated density have shown that the solar corona comprises three distinct morphological regions, streamer, quiet Sun, and polar coronal hole, which except for the streamer region, extend radially into interplanetary space from 1.15Rs to at least 30Rs. …