Search Publications
Including stereoscopic information in the reconstruction of coronal magnetic fields
Wiegelmann, T.; Neukirch, T.
We present a method to include stereoscopic information about the three-dimensional structure of flux tubes into the reconstruction of the coronal magnetic field. Due to the low plasma beta in the corona we can assume a force-free magnetic field, with the current density parallel to the magnetic field lines. Here we use linear force-free fields fo…
The Most Violent Super-Active Regions in the 22nd and 23rd Cycles
Liu, Yang; Tian, Lirong; Wang, Jinxiu
We survey 14 super-active regions (SARs) in the 22nd cycle and 15 SARs in the 23rd cycle. Each produced major flares and major solar storms. Among them, the 25 most violent super active regions (VSARs) are selected based on five parameters: the largest area of sunspots, X-ray flare index (XRI), 10.7 cm radio flux, proton flux and geomagnetic A
Hybrid Solar Energetic Particle Events Observed on Board Soho
Torsti, J.; Kocharov, L.
We summarize ERNE/SOHO observations of solar energetic particle events associated with impulsive soft X-ray flares and LASCO coronal mass ejections (CMEs). The new observational data support an idea that the >10 MeV proton acceleration may be initiated at different coronal sources, operating in the flaring active region and on the global corona…
Multi-wavelength observations of an X-class flare without a coronal mass ejection.
van Driel-Gesztelyi, L.; Culhane, J. L.; Green, L. M. +2 more
Developments in our knowledge of coronal mass ejections (CMEs) have shown that many of these transients occur in association with solar flares. On the occasions when there is a common occurrence of the eruption and the flare, it is most likely that the flare is of high intensity and/or long-duration (Burkepile, Hundhausen, and Webb, 1994; Munro et…
Variation of the low-degree solar acoustic mode parameters over the solar cycle
Jiménez-Reyes, S. J.; Jiménez, A.; Roca Cortés, T.
VIRGO/SPM is a helioseismic sunphotometer on board SOHO that observes the disk-integrated sunlight irradiance at three different colors (red, green, and blue). The data obtained for SPM since the beginning of the SOHO mission, April 1996, to March 2001 have been used to study the differences of the p-mode parameters during the solar activity cycle…
Radial Flows in Supergranules
Raymond, J.; Hathaway, D. H.; Han, S. +1 more
We determine the radial component of the supergranular flow velocity by examining the center-to-limb variation of the Doppler velocity signal. We acquire individual Doppler images obtained with the MDI instrument on the SOHO spacecraft and process them to remove the p-mode oscillation signal, the axisymmetric flows, the convective blueshift signal…
Dual-filament initiation of a Coronal Mass Ejection: Observations and Model
Grechnev, V. V.; Uralov, A. M.; Lesovoi, S. V. +1 more
We propose a new model for the initiation of solar coronal mass ejections (CMEs) and CME-associated flares. The model is inferred from observations of a quiescent filament eruption in the north-western quadrant of the solar disk on 4 September 2000. The event was observed with the Siberian Solar Radio Telescope (5.7 GHz), the Nobeyama Radioheliogr…
Transition Region Blinkers I. Quiet-Sun Properties
Harrison, R. A.; Parnell, C. E.; Bewsher, D.
An automated method of identifying transition region blinkers is presented. The distribution and general properties of blinkers identified in the quiet Sun are discussed. The blinkers are seen most clearly in the O v (629 Å) transition region emission line, but they also have strong signatures in O iv (554 Å), and the chromospheric line, He i (584…
Transition-Region Blinkers - II. Active-Region Properties
Harrison, R. A.; Parnell, C. E.; Bewsher, D.
The distribution and general properties of events identified in an active region that have the same characteristics as quiet-Sun blinkers are discussed and named `active-region blinkers'. The events are identified using an automated scheme `BLinker Identification Program' (BLIP) which was designed for and tested on quiet-Sun blinkers. Like quiet-S…
EUV Spectroscopic Observations of Spray Ejecta from an X2 Flare
Mason, H. E.; Pike, C. D.
An X2.3 class flare was reported on 10 April 2001 in AR 9415. A halo coronal mass ejection (CME) was associated with this flare. The Coronal Diagnostic Spectrometer (CDS) on board the Solar and Heliospheric Observatory (SOHO), which was running in its daily synoptic mode, recorded a very high-velocity ejection of plasma associated with this activi…