Numerical simulation of a catastrophe model for coronal mass ejections

Forbes, T. G.

doi:10.1029/ja095ia08p11919

Cited by 142 publications

(146 citation statements)

References 41 publications

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“…As many theoretical models have shown, typically the closed magnetic system would rise into the atmosphere to find a new equilibrium height, entraining the surrounding field under the frozen-in condition of the highly conducting coronal plasma (e.g. , Forbes 1990;Ding & Hu 2008). The anchored surrounding field naturally becomes stretched, producing a vertical current sheet beneath the rising magnetic bubble and creating the observed keyhole morphology.…”

Section: Theoretical Implicationsmentioning

confidence: 99%

Rise of a Dark Bubble through a Quiescent Prominence

Toma

Casini

Burkepile

et al. 2008

ApJ

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We report on a dynamical event observed in a quiescent prominence on 2007 November 8: a well-formed dark "bubble" with a bright core rose vertically through the prominence without causing it to erupt. This event was observed in Ha and He i 1083 nm with the instruments of the Mauna Loa Solar Observatory. The dark bubble had a size of over and rose from the prominence base, at an average speed of ∼12 km s , forming Ϫ1 40 a bright compression front as it traversed the prominence. It finally assumed a "keyhole" shape before fading. The bright core embedded in the dark bubble was observed to rise from the solar limb, accelerating from ∼12 to ∼20 km s Ϫ1 , leaving a thin trail of material behind. Subsequent observations indicate that this was not an exceptional event, but rather that similar disturbances do occur occasionally in prominences without disrupting them. In this Letter we present the November 8 observations, and propose a possible interpretation of the physical mechanism behind these dynamic events.

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Section: Theoretical Implicationsmentioning

confidence: 99%

Rise of a Dark Bubble through a Quiescent Prominence

Toma

Casini

Burkepile

et al. 2008

ApJ

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“…From a theoretical point of view, a dynamical photosphere is the common boundary of MHD models forming filaments or flux tubes, such as by emergence of flux (Chen 1996;Chen et al 2000), by shearing motions , by converging flows towards the inversion lines (Priest et al 1994;Forbes 1990), or by diffusion of magnetic field (Amari et al 2000). MHD simulations are useful tools for testing these different mechanisms, which are able to produce a filament and then bring it into an unstable state until the eruption.…”

Section: Introductionmentioning

confidence: 99%

Proper horizontal photospheric flows in a filament channel

Schmieder

Roudier

Mein

et al. 2014

A&A

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Context. An extended filament in the central part of the active region NOAA 11106 crossed the central meridian on Sept. 17, 2010 in the southern hemisphere. It has been observed in Hα with the THEMIS telescope in the Canary Islands and in 304 Å with the EUV imager (AIA) onboard the Solar Dynamic Observatory (SDO). Counterstreaming along the Hα threads and bright moving blobs (jets) along the 304 Å filament channel were observed during 10 h before the filament erupted at 17:03 UT. Aims. The aim of the paper is to understand the coupling between magnetic field and convection in filament channels and relate the horizontal photospheric motions to the activity of the filament.Methods. An analysis of the proper photospheric motions using SDO/HMI continuum images with the new version of the coherent structure tracking (CST) algorithm developed to track granules, as well as the large scale photospheric flows, was performed for three hours. Using corks, we derived the passive scalar points and produced a map of the cork distribution in the filament channel. Averaging the velocity vectors in the southern hemisphere in each latitude in steps of 3.5 arcsec, we defined a profile of the differential rotation. Results. Supergranules are clearly identified in the filament channel. Diverging flows inside the supergranules are similar in and out of the filament channel. Converging flows corresponding to the accumulation of corks are identified well around the Hα filament feet and at the edges of the EUV filament channel. At these convergence points, the horizontal photospheric velocity may reach 1 km s −1 , but with a mean velocity of 0.35 km s −1 . In some locations, horizontal flows crossing the channel are detected, indicating eventually large scale vorticity. Conclusions. The coupling between convection and magnetic field in the photosphere is relatively strong. The filament experienced the convection motions through its anchorage points with the photosphere, which are magnetized areas (ends, feet, lateral extensions of the EUV filament channel). From a large scale point-of-view, the differential rotation induced a shear of 0.1 km s −1 in the filament. From a small scale point-of-view, any convective motions favored the interaction of the parasitic polarities responsible for the anchorages of the filament to the photosphere with the surrounding network and may explain the activity of the filament.

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“…1 Energetic events such as coronal mass ejections (CMEs) 2 are often regarded as a consequence of instability and/or loss of equilibrium in one of these partial toroidal structures. 1,[3][4][5][6][7] One potential CME trigger mechanism is the ideal external kink instability (see, e.g., Török and Kliem 8 ). Despite rapid progress in observational capabilities, the lack of detailed magnetic measurements in crucial areas of the corona has prevented the conclusive study of kink stability in coronal magnetic structures.…”

Section: Introductionmentioning

confidence: 99%

Experimental verification of the Kruskal-Shafranov stability limit in line-tied partial-toroidal plasmas

Öz

Myers

et al. 2011

Physics of Plasmas

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The stability properties of partial toroidal flux ropes are studied in detail in the laboratory, motivated by ubiquitous arched magnetic structures found on the solar surface. The flux ropes studied here are magnetized arc discharges formed between two electrodes in the Magnetic Reconnection Experiment (MRX) [Yamada et al., Phys. Plasmas, 4, 1936]. The three dimensional evolution of these flux ropes is monitored by a fast visible light framing camera, while their magnetic structure is measured by a variety of internal magnetic probes. The flux ropes are consistently observed to undergo large-scale oscillations as a result of an external kink instability. Using detailed scans of the plasma current, the guide field strength, and the length of the flux rope, we show that the threshold for kink stability is governed by the Kruskal-Shafranov limit for a flux rope that is held fixed at both ends (i.e., q a = 1).

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Numerical simulation of a catastrophe model for coronal mass ejections

Cited by 142 publications

References 41 publications

Rise of a Dark Bubble through a Quiescent Prominence

Rise of a Dark Bubble through a Quiescent Prominence

Proper horizontal photospheric flows in a filament channel

Experimental verification of the Kruskal-Shafranov stability limit in line-tied partial-toroidal plasmas

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