Search Publications
SUMER spectral observations of post-flare supra-arcade inflows
Innes, D. E.; McKenzie, D. E.; Wang, Tongjiang
On 21 April 2002 a large eruptive flare on the west limb of the Sun developed a bright, very dynamic, post-flare arcade. In TRACE 195 Å images, a series of dark, sunward moving flows were seen against the bright extreme ultraviolet (EUV) arcade. SUMER obtained a series of spectra of the dark EUV flows in the lines C ii, Fe xii, and Fe xxi at a fix…
Observations of 1000 km s−1 Doppler shifts in 107 K solar flare supra-arcade
Innes, D. E.; McKenzie, D. E.; Wang, Tongjiang
An X1.5 flare on the west limb of the Sun on 21 April 2002 developed a large supra-arcade about 30 min after flare onset. The growth of the supra-arcade can be followed in both TRACE 195 Å images and SUMER spectra. Its growth seems to be associated with dark (in TRACE images), sunward moving channels that descend onto the arcade from above. SUMER …
The Siberian Solar Radio Telescope: the current state of the instrument, observations, and data
Grechnev, V. V.; Uralov, A. M.; Altyntsev, A. T. +8 more
The Siberian Solar Radio Telescope (SSRT) is one of the world's largest solar radio heliographs. It commenced operation in 1983, and since then has undergone several upgrades. The operating frequency of the SSRT is 5.7 GHz. Since 1992 the instrument has had the capability to make one-dimensional scans with a high time resolution of 56 ms and an an…
How are Emerging Flux, Flares and CMEs Related to Magnetic Polarity Imbalance in Midi Data?
Mandrini, C. H.; Démoulin, P.; Green, L. M. +1 more
In order to understand whether major flares or coronal mass ejections (CMEs) can be related to changes in the longitudinal photospheric magnetic field, we study 4 young active regions during seven days of their disk passage. This time period precludes any biases which may be introduced in studies that look at the field evolution during the short-t…
On the kinematic evolution of flare-associated cmes
Moon, Y. -J.; Shanmugaraju, A.; Dryer, M. +1 more
We report a common tendency of the kinematic evolution of three flare-associated coronal mass ejections (CMEs). Their kinematic evolutions are examined using well-observed data (eruptive filaments, X-ray structures, and prominences) very close to the solar surface as well as SOHO/LASCO C2-C3 data. Their height-time data are fitted using three anal…
Statistical Flux Tube Properties of 3D Magnetic Carpet Fields
Priest, E. R.; Parnell, C. E.; Mackay, D. H. +1 more
The quiet-Sun photosphere consists of numerous magnetic flux fragments of both polarities that evolve with granular and supergranular flow fields. These concentrations give rise to a web of intermingled magnetic flux tubes which characterise the coronal magnetic field. Here, the nature of these flux tubes is studied. The photosphere is taken to be…
The Coronal Mass Ejection Waiting-Time Distribution
Wheatland, M. S.
The distribution of times Δt between coronal mass ejections (CMEs) in the Large Angle and Spectrometric Coronagraph (LASCO) CME catalog for the years 1996-2001 is examined. The distribution exhibits a power-law tail ∼(Δt)γ with an index γ≈−2.36±0.11 for large waiting times (Δt>10 hours). The power-law index of the waiting-time distri…
Prominence Motions Observed at High Cadences in Temperatures from 10 000 to 250 000 K
De Pontieu, B.; Kucera, T. A.; Tovar, M.
We report here for the first time observations of prominence velocities over a wide range of temperatures and with a high time cadence. Our study of ultraviolet movies of prominences reveals that multi-thermal features with speeds of 5-70 km s−1 perpendicular to the line of sight are common in the prominences which showed traceable moti…
A Quantitative Method to Optimise Magnetic Field Line Fitting of Observed Coronal Loops
Wiegelmann, T.; Hood, A. W.; Carcedo, L. +2 more
Many authors use magnetic-field models to extrapolate the field in the solar corona from magnetic data in the photosphere. The accuracy of such extrapolations is usually judged qualitatively by eye, where a less judgemental quantitative approach would be more desirable. In this paper, a robust method for obtaining the best fit between a theoretica…
Spectroscopy of Solar Prominences Simultaneously From Space and Ground
Dammasch, I. E.; Wiehr, E.; Stellmacher, G.
We present a comprehensive set of spectral data from two quiescent solar prominences observed in parallel from space and ground: with the VTT, simultaneous two-dimensional imaging of Hβ4862 Å and Caii 8542 Å yields a constant ratio, indicating small spatial pressure variations over the prominence. With the Gregory, simultaneous spectra of Caii 854…