caa a22 4500 445347198 CHVBK 20180317142832.0 cr unu---uuuuu 170323e20111001xx s 000 0 eng 10.1007/s11207-011-9832-4 doi (NATIONALLICENCE)springer-10.1007/s11207-011-9832-4 The Flare-Energy Distributions Generated by Kink-Unstable Ensembles of Zero-Net-Current Coronal Loops [Elektronische Daten] [M. Bareford, P. Browning, R. Vander Linden] It has been proposed that the million-degree temperature of the corona is due to the combined effect of barely detectable energy releases, called nanoflares, that occur throughout the solar atmosphere. Unfortunately, the nanoflare density and brightness implied by this hypothesis means that conclusive verification is beyond present observational abilities. Nevertheless, we investigate the plausibility of the nanoflare hypothesis by constructing a magnetohydrodynamic (MHD) model that can derive the energy of a nanoflare from the nature of an ideal kink instability. The set of energy-releasing instabilities is captured by an instability threshold for linear kink modes. Each point on the threshold is associated with a unique energy release; thus we can predict a distribution of nanoflare energies. When the linear instability threshold is crossed, the instability enters a nonlinear phase as it is driven by current sheet reconnection. As the ensuing flare erupts and declines, the field transitions to a lower energy state, which is modelled by relaxation theory; i.e., helicity is conserved and the ratio of current to field becomes invariant within the loop. We apply the model so that all the loops within an ensemble achieve instability followed by energy-releasing relaxation. The result is a nanoflare energy distribution. Furthermore, we produce different distributions by varying the loop aspect ratio, the nature of the path to instability taken by each loop and also the level of radial expansion that may accompany loop relaxation. The heating rate obtained is just sufficient for coronal heating. In addition, we also show that kink instability cannot be associated with a critical magnetic twist value for every point along the instability threshold. Springer Science+Business Media B.V., 2011 Instabilities nationallicence Magnetic fields nationallicence Magnetic reconnection nationallicence Magnetohydrodynamics (MHD) nationallicence Plasmas nationallicence Sun: corona nationallicence Bareford M. Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, M13 9PL, Manchester, UK aut Browning P. Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, M13 9PL, Manchester, UK aut Vander Linden R. SIDC, Royal Observatory of Belgium, Ringlaan 3, 1180, Brussels, Belgium aut Solar Physics Springer Netherlands 273/1(2011-10-01), 93-115 0038-0938 273:1<93 2011 273 11207 https://doi.org/10.1007/s11207-011-9832-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11207-011-9832-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bareford M. Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, M13 9PL, Manchester, UK aut NATIONALLICENCE 700 1- Browning P. Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, M13 9PL, Manchester, UK aut NATIONALLICENCE 700 1- Vander Linden R. SIDC, Royal Observatory of Belgium, Ringlaan 3, 1180, Brussels, Belgium aut NATIONALLICENCE 773 0- Solar Physics Springer Netherlands 273/1(2011-10-01), 93-115 0038-0938 273:1<93 2011 273 11207 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer