TY  - JOUR
A1  - Kliem, Bernhard
A1  - Lin, J.
A1  - Forbes, T. G.
A1  - Priest, E. R.
A1  - Toeroek, T.
T1  - Catastrophe versus instability for the eruption of a toroadal solar magnetic flux
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - The onset of a solar eruption is formulated here as either a magnetic catastrophe or as an instability. Both start with the same equation of force balance governing the underlying equilibria. Using a toroidal flux rope in an external bipolar or quadrupolar field as a model for the current-carrying flux, we demonstrate the occurrence of a fold catastrophe by loss of equilibrium for several representative evolutionary sequences in the stable domain of parameter space. We verify that this catastrophe and the torus instability occur at the same point; they are thus equivalent descriptions for the onset condition of solar eruptions.
KW  - magnetohydrodynamics (MHD)
KW  - Sun: corona
KW  - Sun: coronal mass ejections (CMEs)
KW  - Sun: filaments, prominences
KW  - Sun: flares
KW  - Sun: magnetic fields
Y1  - 2014
U6  - https://doi.org/10.1088/0004-637X/789/1/46
SN  - 0004-637X
SN  - 1538-4357
VL  - 789
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Yan, Xiaoli
A1  - Xue, Zhike
A1  - Jiang, Chaowei
A1  - Priest, E. R.
A1  - Kliem, Bernhard
A1  - Yang, Liheng
A1  - Wang, Jincheng
A1  - Kong, Defang
A1  - Song, Yongliang
A1  - Feng, Xueshang
A1  - Liu, Zhong
T1  - Fast plasmoid-mediated reconnection in a solar flare
JF  - Nature Communications
N2  - Magnetic reconnection is a multi-faceted process of energy conversion in astrophysical, space and laboratory plasmas that operates at microscopic scales but has macroscopic drivers and consequences. 
Solar flares present a key laboratory for its study, leaving imprints of the microscopic physics in radiation spectra and allowing the macroscopic evolution to be imaged, yet a full observational characterization remains elusive. 
Here we combine high resolution imaging and spectral observations of a confined solar flare at multiple wavelengths with data-constrained magnetohydrodynamic modeling to study the dynamics of the flare plasma from the current sheet to the plasmoid scale. The analysis suggests that the flare resulted from the interaction of a twisted magnetic flux rope surrounding a filament with nearby magnetic loops whose feet are anchored in chromospheric fibrils. Bright cusp-shaped structures represent the region around a reconnecting separator or quasi-separator (hyperbolic flux tube). 
The fast reconnection, which is relevant for other astrophysical environments, revealed plasmoids in the current sheet and separatrices and associated unresolved turbulent motions. 
Solar flares provide wide range of observational details about fundamental processes involved. Here, the authors show evidence for magnetic reconnection in a strong confined solar flare displaying all four reconnection flows with plasmoids in the current sheet and the separatrices.
Y1  - 2022
U6  - https://doi.org/10.1038/s41467-022-28269-w
SN  - 2041-1723
VL  - 13
IS  - 1
PB  - Nature Publishing Group UK
CY  - London
ER  -