Search Publications
Oscillations of the upper chromosphere
Vial, J. -C.; Bocchialini, K.; Lemaire, P. +2 more
Variations of intensity and wavelength in several UV lines have been observed with the SUMER spectroheliometer onboard SOHO, and they have been analysed to obtain oscillation spectra and phase differences between lines of different ions. Lines intensities of neutral or singly ionized atoms (with temperature of formation ≤ 30 000 K) exhibit an incr…
Multiple-Thread Model of a Prominence Observed by SUMER and EIT on SOHO
Wilhelm, K.; Schmieder, B.; Dammasch, I. E. +1 more
A quiescent polar crown prominence was observed at Meudon in Hα and Ca ii lines, and by EIT and SUMER on board SOHO in UV lines from 9 to 10 March 1996. SUMER observed the prominence continuously in a scanning mode between 21:40 UT on 9 March, and 18:13 UT on 10 March, in the nitrogen line N v (λ1238) with a 1 arc sec2 resolution. Altog…
Structure and Dynamics of Interconnecting Loops and Coronal Holes in Active Longitudes
Kosovichev, A. G.; Scherrer, P. H.; Benevolenskaya, Elena E.
Using SOHO/MDI and SOHO/EIT data we study properties and dynamics of interconnected active regions, and the relations between the photospheric magnetic fields and coronal structures in active longitudes during the beginning of solar cycle 23. The emergence of new magnetic flux results in appearance of new interconnecting loops. The existence of st…
Dynamics of polar plumes observed at the 1998 February 26 eclipse
Gurman, J. B.; Lites, B. W.; Elmore, D. F. +5 more
This paper presents first observations of dynamics of the white-light solar corona detected during the few minutes of totality of a solar eclipse. Perturbations of a polar plume associated with an embedded `jet' structure observed simultaneously at 195 Å with the EUV Imaging Telescope (EIT) aboard the SOHO spacecraft lead to estimates of the elect…
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 …