TY  - JOUR
A1  - Louis, Rohan E.
A1  - Kliem, Bernhard
A1  - Ravindra, B.
A1  - Chintzoglou, Georgios
T1  - Triggering an Eruptive Flare by Emerging Flux in a Solar Active-Region Complex
JF  - Solar physics : a journal for solar and solar-stellar research and the study of solar terrestrial physics
N2  - A flare and fast coronal mass ejection originated between solar active regions NOAA 11514 and 11515 on 2012 July 1 (SOL2012-07-01) in response to flux emergence in front of the leading sunspot of the trailing region 11515. Analyzing the evolution of the photospheric magnetic flux and the coronal structure, we find that the flux emergence triggered the eruption by interaction with overlying flux in a non-standard way. The new flux neither had the opposite orientation nor a location near the polarity inversion line, which are favorable for strong reconnection with the arcade flux under which it emerged. Moreover, its flux content remained significantly smaller than that of the arcade (). However, a loop system rooted in the trailing active region ran in part under the arcade between the active regions, passing over the site of flux emergence. The reconnection with the emerging flux, leading to a series of jet emissions into the loop system, caused a strong but confined rise of the loop system. This lifted the arcade between the two active regions, weakening its downward tension force and thus destabilizing the considerably sheared flux under the arcade. The complex event was also associated with supporting precursor activity in an enhanced network near the active regions, acting on the large-scale overlying flux, and with two simultaneous confined flares within the active regions.
KW  - Flares, dynamics
KW  - Sunspots, magnetic fields
KW  - Chromosphere, active
KW  - Corona
KW  - Prominences, active
Y1  - 2015
U6  - https://doi.org/10.1007/s11207-015-0726-8
SN  - 0038-0938
SN  - 1573-093X
VL  - 290
IS  - 12
SP  - 3641
EP  - 3662
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Thompson, W. T.
A1  - Kliem, Bernhard
A1  - Toeroek, Tibor
T1  - 3D reconstruction of a rotating erupting prominence
JF  - Solar physics : a journal for solar and solar-stellar research and the study of solar terrestrial physics
N2  - A bright prominence associated with a coronal mass ejection (CME) was seen erupting from the Sun on 9 April 2008. This prominence was tracked by both the Solar Terrestrial Relations Observatory (STEREO) EUVI and COR1 telescopes, and was seen to rotate about the line of sight as it erupted; therefore, the event has been nicknamed the "Cartwheel CME." The threads of the prominence in the core of the CME quite clearly indicate the structure of a weakly to moderately twisted flux rope throughout the field of view, up to heliocentric heights of 4 solar radii. Although the STEREO separation was 48A degrees, it was possible to match some sharp features in the later part of the eruption as seen in the 304 line in EUVI and in the H alpha-sensitive bandpass of COR1 by both STEREO Ahead and Behind. These features could then be traced out in three-dimensional space, and reprojected into a view in which the eruption is directed toward the observer. The reconstructed view shows that the alignment of the prominence to the vertical axis rotates as it rises up to a leading-edge height of a parts per thousand aEuro parts per thousand 2.5 solar radii, and then remains approximately constant. The alignment at 2.5 solar radii differs by about 115A degrees from the original filament orientation inferred from H alpha and EUV data, and the height profile of the rotation, obtained here for the first time, shows that two thirds of the total rotation are reached within a parts per thousand aEuro parts per thousand 0.5 solar radii above the photosphere. These features are well reproduced by numerical simulations of an unstable moderately twisted flux rope embedded in external flux with a relatively strong shear field component.
KW  - Corona, active
KW  - Prominences, active
KW  - Coronal mass ejections
KW  - Initiation and propagation
KW  - Magnetic fields, corona
Y1  - 2012
U6  - https://doi.org/10.1007/s11207-011-9868-5
SN  - 0038-0938
VL  - 276
IS  - 1-2
SP  - 241
EP  - 259
PB  - Springer
CY  - Dordrecht
ER  -