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Structure and Dynamics of the Corona Surrounding an Eruptive Prominence
Gopalswamy, N.; Hudson, H. S.; Hanaoka, Y.
We report on the 1997 December 14 prominence eruption event that was accompanied by eruptive signatures in X-rays, EUV and white light: coronal dimming, X-ray arcade formation , X-ray brightenings, EUV eruption, and a white light CME. The data used were obtained by the Nobeyama Radioheliograph, Yohkoh Soft X-ray Telescope (SXT) and SOHO/LASCO and …
Recent Observations of the Heliospheric Magnetic Field at Ulysses: Return to Low Latitude
Balogh, A.; Tsurutani, B. T.; Smith, E. J. +2 more
Ulysses recently completed a second slow latitude scan of the northern heliosphere, a descent from 80.2°N in July 1995 to the solar equator in December 1997. These recent magnetic field observations complement those from the south hemisphere and reveal new features as well as the effect of the changing solar cycle. Five topics are emphasized in th…
Hot Cores in Coronal Filament Cavities
Schwenn, R.; Hudson, H.
Filaments represent cold intrusions in the corona, embedded in magnetic configurations termed ``filament cavities.'' Such cavities may occur without actually containing prominence material. A cavity then may erupt, leading to a coronal mass ejection (CME). Studies of Yohkoh soft X-ray images have previously shown that such eruptions may contain el…
Multispectral Observations of Jupiter's Aurora
Walker, R. J.; Trafton, L. M.; Clarke, J. T. +10 more
Remote sensing of Jupiter's aurora from x-ray to radio wavelengths has revealed much about the nature of the jovian aurora and about the impact of ionosphere-magnetosphere coupling on the upper atmosphere of Jupiter. As indicated by the combination of x-ray and ultraviolet observations, both energetic heavy ions and electrons energized in the oute…
Galactic Cosmic Ray Observations at Different Heliospheric Latitudes
Heber, Bernd; Potgieter, Marius S.
The local interstellar spectra (LIS) of galactic cosmic rays at low energies cannot be determined from measurements made near Earth, because of strong solar modulation processes from the heliospheric boundary to the observer. Computations done in the seventies based on Parker's cosmic ray modulation theory taking into account diffusion, convection…
Hydrogen and Oxygen Temperatures in Coronal Holes
Giordano, S.; Antonucci, E.; Dodero, M. A.
The analysis of the O VI λ 1032 and 1037 and H I Ly⋋a ⋋l 1216 line profiles, observed with the Ultraviolet Coronagraph Spectrometer (UVCS) onboard the Solar Heliospheric Observatory (SOHO) in a polar coronal hole within 1.5 Rsolar and 3.5 Rsolar during the solar activity minimum, indicates the existence of a large anisotropy in the velocity distri…
Heliospheric 3d Structure and CME Propagation as Seen from SOHO: Recent Lessons for Space Weather Predictions
Schwenn, R.
Observations from Skylab, Helios, Ulysses, and SOHO have demonstrated how closely the 3D heliosphere is related to the underlying coronal structure. Around solar activity minimum, the large polar coronal holes dominate the major part of the heliosphere, through the high-speed solar wind streams emanating from them. A distinctively different type o…
On the Electron Temperatures, Densities and Hot Ions in Coronal Hole Plasma Observed by Sumer on SOHO
Dwivedi, B. N.; Mohan, A.; Wilhelm, K.
Making use of high-resolution ultraviolet observations obtained with SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on the spacecraft SOHO (Solar and Heliospheric Observatory), we study plasma temperatures, densities and hot ions in polar coronal holes (source region of the high-speed solar wind). In particular, we present spectroscop…
Observation of Shock Waves Associated with Coronal Mass Ejections from SOHO/LASCO
Kosovichev, A. G.; Stepanova, T. V.
Theoretical models of coronal mass ejections (CME) predict formation of shock waves in front of eruptive magnetic structures, loops and arches. These shock waves have been detected in the solar wind at large distances from the Sun. However, their observation at short distances in the solar corona has been difficult. We have attempted to identify t…
Oxygen Outflow Velocities in a Polar Coronal Hole
Giordano, S.; Antonucci, E.; Dodero, M. A.
The expansion velocity of the solar corona in a polar coronal hole during the minimum of solar activity is inferred from an analysis of the intensities and profiles of the O VI λ 1032, 1037 lines observed with the Ultraviolet Coronagraph Spectrometer (UVCS), operating onboard the Solar Heliospheric Observatory (SOHO). The outflow velocity of the o…