Search Publications
Transient Magnetic and Doppler Features Related to the White-Light Flares in NOAA 10486
Maurya, R. A.; Ambastha, A.
Rapidly moving transient features have been detected in magnetic and Doppler images of super-active region NOAA 10486 during the X17/4B flare of 28 October 2003 and the X10/2B flare of 29 October 2003. Both these flares were extremely energetic white-light events. The transient features appeared during impulsive phases of the flares and moved with…
Time - Distance Solar Far-Side Imaging Using Three-Skip Acoustic Signals
Zhao, J.; Hartlep, T.; Ilonidis, S.
The purpose of this work is to image solar far-side active regions using acoustic signals with three skips and improve the quality of existing images. The mapping of far-side active regions was first made possible using the helioseismic holography technique by use of four-skip acoustic signals. The quality of far-side images was later improved wit…
Type II bursts in Meter and Decameter - Hectometer Wavelength Ranges and Their Relation to Flares and CMEs
Prakash, O.; Shanmugaraju, A.; Vršnak, Bojan +1 more
Statistical analysis of the relationship between type II radio bursts appearing in the metric (m) and decameter-to-hectometer (DH) wavelength ranges is presented. The associated X-ray flares and coronal mass ejections (CMEs) are also reported. The sample is divided into two classes using the frequency-drift plots: Class I, representing those event…
Modeling a Shallow Solar Dynamo
Schatten, Kenneth H.
Photospheric ephemeral regions (EPRs) cover the Sun like a magnetic carpet. From this, we update the Babcock - Leighton solar dynamo. Rather than sunspot fields appearing in the photosphere de novo from eruptions originating in the deep interior, we consider that sunspots form directly in the photosphere by a rapid accumulation of like-sign field …
An EUV Jet and Hα Filament Eruption Associated with Flux Cancelation in a Decaying Active Region
Chen, Huadong; Ma, Suli; Jiang, Yunchun
Using data from the Transition Region and Coronal Explorer (TRACE), Solar and Heliospheric Observatory (SOHO), Ramaty High Energy Solar Spectroscopic Imager (RHESSI), and Hida Observatory (HO), we present a detailed study of an EUV jet and the associated Hα filament eruption in a major flare in the active region NOAA 10044 on 29 July 2002. In the …
3D Reconstruction of the Leading Edge of the 20 May 2007 Partial Halo CME
Mierla, M.; Inhester, B.; Srivastava, N. +1 more
We have reconstructed the leading edge of a coronal mass ejection (CME) observed on 20 May 2007 by COR1 and COR2 of the SECCHI suite onboard the twin STEREO spacecraft. The reconstruction of the leading edge of this CME was achieved using the tie-pointing method based on epipolar geometry. The true speeds derived from the reconstruction of the lea…
Type II Radio Bursts with High and Low Starting Frequencies
Moon, Y. -J.; Shanmugaraju, Annamalai; Vrsnak, Bojan
We report on the detailed analysis of i) differences between the properties of type IIs with various starting frequencies (high: ≥100 MHz; low: ≤50 MHz; mid: 50 MHz ≤f≤ 100 MHz) and ii) the properties of CMEs and flares associated with them. For this study, we considered a sample of type II radio bursts observed by Culgoora radio spectrograph from…
A Cross-Comparison of Cotemporal Magnetograms Obtained with MDI/SOHO and SP/ Hinode
Li, H.; Zhang, H. Q.; Zhang, M. +1 more
We compared a set of cotemporal magnetograms of active regions obtained with the Michelson Doppler Imager (MDI) aboard SOHO and the Spectro-Polarimeter (SP) of the Solar Optical Telescope (SOT) on board Hinode. The comparison shows that even with the recent calibration of level-1.8 data, the magnetic flux density derived from the MDI data is still…
Three-Dimensional Kinematics of Coronal Mass Ejections from STEREO/SECCHI-COR2 Observations in 2007 - 2008
Llebaria, A.; Lamy, P.; Boursier, Y.
We present a new method to perform the three dimensional characterization of coronal mass ejections (CMEs) using stereoscopic images obtained with the STEREO/SECCHI-COR2 coronagraphs. Two approaches are proposed, and each associated algorithm gives the trajectory of the CME and its kinematical properties (velocity and acceleration profiles) intend…
The Ulysses Catalog of Solar Hard X-Ray Flares
Hurley, K.; Hudson, H. S.; Tranquille, C.
Ulysses was launched in October 1990, and its Solar X-ray/Cosmic Gamma-Ray Burst Experiment (GRB) has provided more than 13 years of uninterrupted observations of solar X-ray flare activity. Due to the large variation of the relative solar latitude and longitude of the spacecraft orbit with respect to the Earth, the perspective of the GRB instrume…