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The Sun and the Solar Wind Close to the Sun
Suess, S. T.
One of the benefits of the Ulysses, SOHO, and YOHKOH missions has been a strong stimulus to better understand the magnetohydrodynamic processes involved in coronal expansion. Three topics for which this has been especially true are described here. These are: (i) The observed constancy of the radial interplanetary magnetic field strength (as mapped…
3-D Magnetic Configurations for Filaments and Flares: The Role of ``Magnetic Dips'' and ``Bald Patches''
Vial, J. -C.; van Driel-Gesztelyi, L.; Aulanier, G. +8 more
The 3-D magnetic configuration of a filament and of a low energy flare is reconstructed, using linear mag- netohydrostatic (lmhs) extrapolations. In both cases, we find observational signatures of energy release at the locations of computed ``bald patches'' separatrices, characterised by field lines which are tangent to the photosphere.The filamen…
On the Sources of Jovian Hectometric Radiation
Misawa, H.; Morioka, A.; Nakagawa, F.
Jovian hectometric radiation(HOM) emitted from the polar region of the Jovian magnetsphere reflects the information on the electro-magnetic environment of the source region. Using the Ulysses URAP and SWOOPS data, the occurrence characteristics of HOM and its relation to the solar wind were investigated. As a result, we found that HOM can be class…
Study of CME Structure and Evolution Deduced from Ulysses/Hi-Scale Energetic Particle Observations
Malandraki, O.; Sidiropoulos, N.; Saris, E. T. +1 more
In this work, we study the anisotropy characteristics of solar energetic electron (E > 53 keV) fluxes observed by the ULYSSES/HI-SCALE instrument during the passage of a well-identified Coronal Mass Ejection. On the basis of the energetic electron observations, firm conclusions are drawn on whether the detected Coronal Mass Ejection has been de…
Numerical Simulations of Trapped Slow Magnetosonic Waves in Solar Coronal Plumes
Ofman, L.; Deforest, C. E.
Recent observations of polar plumes in the southern solar coronal hole by the Extreme ultraviolet Imaging Telescope (EIT) on board the SOHO spacecraft show signatures of quasi-periodic compressional waves. Here, we present the results of a nonlinear, 2D MHD simulation of the slow magnetosonic waves in plumes for typical coronal conditions consiste…
Solar Prominences Observed by Soho (SUMER, CDS, EIT) and Ground-Based Observatories (GBO)
Heinzel, P.; Schmieder, B.; Rudawy, P. +1 more
We present two sets of prominence observations in higher lines of the hydrogen Lyman series (from Lδ to L-9), together with some other UV lines. These data have been obtained by the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) onboard the SOHO satellite in June 1997. Coordinated observations were also taken by other SOHO instruments…
Search for Velocity Variations in Fe XIV 5304 A&ring Coronagraph Observations Near Activity Minimum
Howard, R. A.; Wood, B. E.; Karovska, M. +4 more
The LASCO C1 coronagraph on the SOHO satellite observes the solar corona from 1.1 to 3.0 Ro, and contains a Fabry-Perot interferometer which can image the corona in the 1.8 million K Fe XIV green line. We designed an observing program with reduced spatial coverage and reduced profile coverage at only three wavelengths to study coronal heating in o…
Structure and Dynamics in the Atmosphere Above Sunspot Regions
Kjeldseth-Moe, O.; Haugan, S. V. H.; Brekke, P. +3 more
Based on simultaneous observations of 10 EUV emission lines with the Coronal Diagnostic Spectrometer - CDS on the Solar and Heliospheric Observatory - SOHO we study the spatial distributions of both line emission and line-of-sight velocity in the atmosphere above 17 sunspots. We find that both the enhanced EUV line emissions and the velocities are…
The Dynamical and Time Variable Solar Transition Region Observed with the Coronal Diagnostic Pectrometer (CDS) on Soho
Kjeldseth-Moe, O.
CDS on SOHO has detected an upper solar atmosphere that is more dynamic and time variable than previously expected. Exciting and unexpected is the strongly time variable and dynamic active region loops at transition region temperatures. Loops in the temperature range of 1-5 × 105 K, extending 20 000 - 90 000 km above the solar surface, …
Interplanetary Disturbances Through the Minimum to the Maximum Solar Activities
Kojima, Masayoshi; Tokumaru, Munetoshi; Watanabe, Takashi
A comparative study of three-dimensional propagation properties of transient interplanetary disturbances is made for two different phases of 11-year solar activity; early ascending phase (November 1997) and the maximum phase (June 1991). These events were apparently associated with solar flares. Principal data source is solar wind speed measuremen…