Search Publications
Three-dimensional reconstruction of UV emissivities in the solar corona using Ultraviolet Coronagraph Spectrometer data from the Whole Sun Month
Panasyuk, Alexander V.
UV coronal intensity data collected by the Ultraviolet Coronagraph Spectrometer on SOHO in a daily synoptic program during the Whole Sun Month are used to reconstruct the three-dimensional distribution of emissivities in the solar corona for H I Ly α and the O VI doublet at 1032 and 1037 Å. We discuss the specifics that complicate a tomographic re…
On the determination of electron polytrope indices within coronal mass ejections in the solar wind
Gosling, J. T.
Electron temperature and density often appear to be negatively correlated with one another as a coronal mass ejection, CME, in the solar wind passes over a spacecraft at 1 AU and beyond. It has been suggested that this negative correlation within magnetic clouds, which form a subset of all CMEs, implies that the electron polytropic index for the p…
Solar wind ionic charge states during the Ulysses pole-to-pole pass
Galvin, Antoinette B.; Gloeckler, George; Ko, Yuan-Kuen +1 more
We analyze and compare the ionic charge composition data for different types of the solar wind (slow wind from equatorial regions, fast wind from low-latitude coronal hole and fast wind from both south and north polar coronal hole) which the Solar Wind Ion Composition Spectrometer (SWICS) on Ulysses observed during the pole-to-pole pass of its pri…
Energetic (~10-65 MeV) protons observed by ERNE on August 13-14, 1996: Eruption on the solar back side as a possible source of the event
Laitinen, T.; Vainio, R.; Valtonen, E. +6 more
The onset of the >10-MeV proton event of August 13-14, 1996, revealed a velocity dispersion, which is a signature of its solar origin, but no associated soft X ray flare was observed. The LASCO CME observations, the presence of AR 7981 beyond the west limb, and type II and IV radio burst timing with respect to the proton event onset indicate th…
Evidence for Langmuir envelope solitons in solar type III burst source regions
MacDowall, R. J.; Goldstein, M. L.; Stone, R. G. +2 more
We present observational evidence for the generation of Langmuir envelope solitons in the source regions of solar type III radio bursts. The solitons appear to be formed by electron beams which excite either the modulational instability or oscillating two-stream instability (OTSI). Millisecond data from the Ulysses Unified Radio and Plasma Wave Ex…
The Fe/O elemental abundance ratio in the solar wind as observed with SOHO CELIAS CTOF
Wurz, P.; Bochsler, P.; Ipavich, F. M. +4 more
Using data of the Charge Time-of-Flight (CTOF) mass spectrometer of the Charge, Element, and Isotope Analysis System (CELIAS) on board the Solar and Heliospheric Observatory (SOHO) from ~80 days of observation around solar minimum we derive a value for the Fe/O abundance ratio for the inecliptic solar wind of 0.11+/-0.03. Since Fe has a low first …
Can Kelvin-Helmholtz instabilities of jet-like structures and plumes cause solar wind fluctuations at 1 AU?
Suess, S. T.; Parhi, S.; Sulkanen, M.
The long high-latitude sampling of Ulysses provides the opportunity to study fine structures. At latitudes poleward of ~-60° the solar wind had fluctuations in velocity gradients which were attributed to ``microstreams.'' The data also suggested fluctuations characterized by magnetic plus thermal pressure balance structures ('PBS'). At higher freq…
Whole Sun Month at solar minimum: An introduction
Kohl, John L.; Galvin, Antoinette B.
The Whole Sun Month was a collaborative project of the IACG Campaign 4 and the SOHO Joint Observing Programs to characterize and model the structure of the global corona during solar minimum conditions. This introduction provides a brief description of the campaign objectives, the missions, and observatories involved and highlights some of the sci…
Combined Ulysses solar wind and SOHO coronal observations of several west limb coronal mass ejections
Schwenn, R.; Forsyth, R. J.; Riley, P. +4 more
From October 1996 to January 1997, Ulysses was situated roughly above the west limb of the Sun as observed from Earth at a heliocentric distance of about 4.6 AU and a latitude of about 25°. This presents the first opportunity to compare Solar and Heliospheric Observatory (SOHO) limb observations of coronal mass ejections (CMEs) directly with their…
Observations of Jovian upstream events by Ulysses
Armstrong, T. P.; Haggerty, Dennis
The heliosphere instrument for spectra composition and anisotropy at low energy (HISCALE) experiment on board the Ulysses spacecraft, during the Jovian flyby, measured 192 distinct 61-77 keV upstream ion events of probable Jovian origin. Event-averaged characteristics such as intensities, anisotropies, power law spectral exponents, averaged event …