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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 …
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…
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…
SWAN/SOHO H Cell Measurements: The First Year
Bertaux, Jean-Loup; Lallement, Rosine; Quémerais, Eric +3 more
We present here an analysis of one year of data obtained by the SWAN instrument on board the SOHO spacecraft orbiting around the L1 Lagrange point at 1.5 × 106 km sunward from Earth. This instrument is measuring the interplanetary Lyman ca background due to solar photons backscattered by hydrogen atoms in the interplanetary medium. The …
Large-Scale Evolution of the Active Region NOAA 7978, 7981, 7986 Observed by Goes, Soho, and Yohkoh
van Driel-Gesztelyi, L.; Foing, B.; Fludra, A. +3 more
We took part in a joint project aimed to study the large-scale evolution of an active region from its emergence throughout its decay for several solar rotations. Our interest focuses on the understanding of how energy is generated, released, deposited, and transformed in active regions. To this end, we determined physical parameters like intensity…
Coronal Mass Ejections and the Solar Wind: New Results from LASCO
Howard, R. A.; Dere, K. P.; Brueckner, G. E.
The LASCO and EIT experiments on SOHO have provided a revolutionary picture of coronal dynamics. In the past, the corona has largely been thought to be a region where the evolution of the coronal structures occurred on relatively large time scales, aside from the intermittent coronal mass ejection. The outflows in the polar coronal holes were larg…