Search Publications
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 …
Surface and Sub-surface Electrical Measurement of Titan with the PWA-HASI Experiment on Huygens
Rodrigo, R.; López-Moreno, J. J.; Fulchignoni, M. +11 more
The Permittivity Waves and Altimetry (PWA) experiment is part of the Huygens Atmospheric Structure Instrument (HASI) presently `en route' toTitan as a part of the HUYGENS Probe carried by the Saturn orbiter CASSINI. When HUYGENS lands upon Titan, the Mutual Impedance (MI) probe, part of the PWA experiment will be set to a special mode to measure t…
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…
Non-Radial Unipolar Coronal Streamers in Magnetically High Latitudes and Radial Bipolar Streamers at the Magnetic Equator of the Sun
Shibata, K.; Dere, K. P.; Saito, Takao +1 more
The complex structure of coronal streamers can be better understood by their classification into two classes: non-radial unipolar streamers emanating from magnetically high latitudes, and radial bipolar streamers emanating from the magnetic equator. The coronal streamers observed during the total solar eclipses of July 11,1991 and February 26, 199…
Comparisons of Interplanetary Scintillation and Optical Measurements of Solar Wind Acceleration with Model Results
Thompson, B. J.; Breen, A. R.; de Forest, C. F. +4 more
Observations of the fast, high latitude solar wind show that acceleration of the fast wind is complete by 10 solar radii (R), while measurements from the LASCO instrument on SOHO show that most of the acceleration takes place inside 5 R. A series of observations were made in September 1997 using EISCAT and the C2 and C3 coronagraphs aboard SOHO to…
Energetic Particle Signatures of a Corotating Interaction Region from a High Latitude Coronal Hole: SOHO, Wind and Ulysses Observations
Thompson, B. J.; Lazarus, A. J.; Kunow, H. +10 more
In mid 1996 the Comprehensive Suprathermal and Energetic Particle Analyser (COSTEP) onboard the Solar and Heliospheric Observatory, at 1 AU in the ecliptic plane, detected recurrent periods of enhanced MeV ions in association with a corotating interaction region (CIR). Measurements of energetic ions from the Cosmic Ray and Solar Particle Instrumen…