Search Publications
An investigation of the fine ray structure of the coronal streamer belt using LASCO data
Eselevich, M. V.; Eselevich, V. G.
It is shown that within R>3-4 R⊙from the solar center the coronal streamer belt consists in a sequence of radial brightness rays. A minimum angular size of the individual ray d≈2.0°-2.5°, which is about the same in the directions normal to and along the streamer-belt, is independent of the distance from the Sun at R=4-6 R⊙…
SOHO/SUMER observations and analysis of hydrogen Lyman lines in a quiescent prominence
Heinzel, P.; Schmieder, B.; Rudawy, P. +1 more
A quiescent prominence was observed in June 1997 by instruments onboard the SOHO spacecraft: the Solar Ultraviolet Measurements of Emitted Radiation (SUMER), Coronal Diagnostic Spectrometer (CDS) and Extreme-Ultraviolet Imaging Telescope (EIT), along with the coronagraph of the Wrocław University Observatory at Bialków and the spectrograph of the …
Resonance Scattering of 30.4 NM Chromospheric Radiation by Coronal Singly Ionized Helium Observed with EIT
Delaboudinière, J. P.
A diffuse emission is observed above the solar limb in the `304 Å' channel of the Extreme-Ultraviolet Imaging Telescope (EIT) onboard the SOHO spacecraft. Part of this emission is attributed to the presence of residual singly-ionized helium in the solar corona, which resonantly scatters the intense helium `Lyman alpha' radiation of the chromospher…
Coronal velocity measurements with Ulysses: multi-link correlation studies during two superior conjunctions
Pätzold, M.; Plettemeier, D.; Janardhan, P. +5 more
A well-known method for studying the solar wind very close to the Sun (heliocentric distances: 4 to 40 solar radii) is by radio sounding between a spacecraft at superior conjunction and the Earth. The Ulysses Solar Corona Experiment was performed at the spacecraft's two solar conjunctions in summer 1991 and winter 1995, during which dual-frequency…
Coronal Radiation and Helium λ584 Emission in Active Regions
Fredvik, T.; Maltby, P.
Based on EUV observations of eleven sunspot regions obtained with the Coronal Diagnostic Spectrometer, CDS, on SOHO we have studied the spatial distribution, temporal variation and wavelength shift of the He i λ584 line. We find a relatively high spatial correlation between the coronal line Fe xvi λ360 and the He i λ584 line. This points to corona…
Multiresolution wavelet analysis of SUMER/SOHO observations in a solar prominence
Vial, J. -C.; Bocchialini, K.; Rovira, M. +3 more
We have studied through a multiresolution wavelet analysis the oscillations in a limb prominence. Intensity fluctuations in time and height corresponding to different lines of Si iv and O iv observed with SUMER on board SOHO have been analyzed in the wavelet bands of J3= 1 min 36 s to 3 min 12 s and J4=3 min 12 s to 6 min 24 …
Forward modeling of the coronal response to reconnection in an X-ray bright point
Longcope, Dana; Kankelborg, Charles
We use MDI magnetic field observations and the theory of reconnection through a separator to constrain a numerical simulation of an X-ray bright point observed in EUV by TRACE. A gasdynamic model is employed to describe the corona and transition region in the bright point loop. Nonlocal effects such as opacity and ambipolar diffusion are important…
Multiple CME Events Observed With LASCO
Simnett, G. M.; Lyons, M. A.
Observations are reported of two multiple CME events which were detected on 2-3 June 1997 and 9-10 June 1998, using the LASCO instrument on board SOHO. Each event consists of a group of four related CMEs which emerge from progressively higher latitudes over a time period of approximately 16 hours. In both cases there is on-disk activity visible in…
Filament channel structures in a SI IV line related to a 3d magnetic model
Vial, J. -C.; Aulanier, G.; Schmieder, B. +2 more
A recent 3D magnetic model of filament support (Aulanier and Démoulin, 1998) has shown that specific morphologies derived from the model, based on SOHO/MDI magnetograms, match quite well with the observations of a filament observed in Hα and Ca ii lines with the German telescope VTT in Tenerife on 25 September 1996 (Aulanier et al., 1998, 1999a). …
Observations and Modeling of an Explosive Coronal Mass Ejection as Observed by LASCO
Wu, S. T.; Andrews, M. D.; Wang, A. -H.
We present a qualitative and quantitative comparison of a single coronal mass ejection (CME) as observed by LASCO on 5 October 1996 with the results of a two-dimensional magnetohydrodynamic (MHD) model. This event was selected as a clear example of a CME that is not caused by the disruption of a helmet streamer. This CME occurs against the backgro…