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On the Temporal Relationship between Coronal Mass Ejections and Flares
Zhang, J.; Howard, R. A.; Kundu, M. R. +2 more
The temporal relationship between coronal mass ejections (CMEs) and associated solar flares is of great importance to understanding the origin of CMEs, but it has been difficult to study owing to the nature of CME detection. In this paper, we investigate this issue using the Large Angle and Spectrometric Coronagraph and the EUV Imaging Telescope o…
Radio Signatures of Coronal Mass Ejection Interaction: Coronal Mass Ejection Cannibalism?
Kaiser, M. L.; Howard, R. A.; Gopalswamy, N. +2 more
We report the first detection at long radio wavelengths of interaction between coronal mass ejections (CMEs) in the interplanetary medium. The radio signature is in the form of intense continuum-like radio emission following an interplanetary type II burst. At the time of the radio enhancement, coronagraphic images show a fast CME overtaking a slo…
Clear Evidence of Reconnection Inflow of a Solar Flare
Yokoyama, T.; Akita, K.; Morimoto, T. +2 more
We found an important piece of evidence for magnetic reconnection inflow in a flare on 1999 March 18. The flare occurred on the northeast limb, displaying a nice cusp-shaped soft X-ray loop and a plasmoid ejection typical for the long-duration events. The EUV observation of the same flare shows us a bubble-like void ejection. The core of this EUV …
Observational Determination of the Rate of Magnetic Helicity Transport through the Solar Surface via the Horizontal Motion of Field Line Footpoints
Chae, Jongchul
Magnetic helicity may be transported to the solar corona through the solar surface either via the passage of helical magnetic field lines from below or via the shuffling of footpoints of preexisting coronal field lines. In this Letter, we show how to observationally determine the rate of magnetic helicity transport via photospheric footpoint shuff…
Investigation of Mass Flows beneath a Sunspot by Time-Distance Helioseismology
Zhao, Junwei; Kosovichev, Alexander G.; Duvall, Thomas L., Jr.
A time-distance helioseismic technique is employed to analyze a set of high-resolution Dopplergram observations of a large sunspot by SOHO/MDI on 1998 June 18. A regularized, damped least-squares inversion is applied to the measurements of travel times to infer mass flows around the sunspot below the solar surface. Powerful converging and downward…
The Formation of a Prominence in Active Region NOAA 8668. I. SOHO/MDI Observations of Magnetic Field Evolution
Qiu, Jiong; Wang, Haimin; Chae, Jongchul +3 more
We have studied the evolution of the photospheric magnetic field in active region NOAA 8668 for 3 days while the formation of a reverse S-shaped filament proceeded. From a set of full-disk line-of-sight magnetograms taken by the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO), we have found a large canceling m…
Are Magnetic Dips Necessary for Prominence Formation?
Klimchuk, J. A.; MacNeice, P. J.; Antiochos, S. K. +2 more
The short answer: No.
Magnetic Energy Release and Transients in the Solar Flare of 2000 July 14
Kosovichev, A. G.; Zharkova, V. V.
High-resolution observations of a large solar flare on 2000 July 14 (``Bastille Day Flare'') from the Michelson Doppler Imager instrument on the SOHO spacecraft reveal rapid variations of the magnetic field in the lower solar atmosphere during the flare. Some of these variations were irreversible, occurred in the vicinity of magnetic neutral lines…
The Coronal Mass Ejection of 1998 April 20: Direct Imaging at Radio Wavelengths
Pick, M.; Kerdraon, A.; Vourlidas, A. +2 more
We observed the fast coronal mass ejection (CME) of 1998 April 20 with the radioheliograph at Nançay, France, between 164 and 432 MHz. Spectroscopic data were obtained between 40 and 800 MHz by the spectrometer at Tremsdorf, Germany, and between 20 kHz and 14 MHz with the WAVES instrument on board the Wind spacecraft. Energetic particle data were …
Evolution of Two EIT/Hα Moreton Waves
Vršnak, B.; Hanslmeier, A.; Aurass, H. +1 more
Since the discovery of EIT waves, questions have remained about the driver of these disturbances and their association with the chromospheric Moreton waves. In order to resolve some of these issues, two flare-associated transient events (1997 November 3 and 1998 May 2) observed simultaneously in Hα and EIT are analyzed. The cospatiality of Moreton…