Pre-eruption processes: heating, particle acceleration and the formation of a hot channel before the 2012 October 20 M9.0 limb flare. (arXiv:1902.08436v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Hernandez_Perez_A/0/1/0/all/0/1">Aaron Hernandez-Perez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Su_Y/0/1/0/all/0/1">Yang Su</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Veronig_A/0/1/0/all/0/1">Astrid M. Veronig</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Thalmann_J/0/1/0/all/0/1">Julia K. Thalmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gomory_P/0/1/0/all/0/1">Peter Gömöry</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Joshi_B/0/1/0/all/0/1">Bhuwan Joshi</a>
We report a detailed study of the pre-eruption activities that led to the
occurrence of an M9.0 flare/CME event on 2012 October 20 in NOAA AR 11598. This
includes the study of the preceding confined C2.4 flare that occurred on the
same AR ~25 minutes earlier. We observed that the M9.0 flare occurred as a
consequence of two distinct triggering events well separated in time. The first
triggering episode occurred as early as ~20 minutes before the onset of the
M9.0 flare, evidenced by the destabilization and rise of a pre-existing
filament to a new position of equilibrium at a higher coronal altitude during
the decay phase of the C2.4 flare. This brought the system to a magnetic
configuration where the establishment of the second triggering event was
favorable. The second triggering episode occurred ~17 minutes later, during the
early phase of the M9.0 flare, evidenced by the further rise of the filament
and successful ejection. The second trigger is followed by a flare precursor
phase, characterized by non-thermal emission and the sequential formation of a
hot channel as shown by the SDO/AIA DEM (differential emission measure) maps,
the RHESSI X-ray images and spectra. These observations are suggestive of
magnetic reconnection and particle acceleration that can explain the precursor
phase and can be directly related to the formation of the hot channel. We
discuss on the triggering mechanisms, their implications during the early and
precursor phases and highlight the importance of early activities and preceding
small confined flares to understand the initiation of large eruptive flares.
We report a detailed study of the pre-eruption activities that led to the
occurrence of an M9.0 flare/CME event on 2012 October 20 in NOAA AR 11598. This
includes the study of the preceding confined C2.4 flare that occurred on the
same AR ~25 minutes earlier. We observed that the M9.0 flare occurred as a
consequence of two distinct triggering events well separated in time. The first
triggering episode occurred as early as ~20 minutes before the onset of the
M9.0 flare, evidenced by the destabilization and rise of a pre-existing
filament to a new position of equilibrium at a higher coronal altitude during
the decay phase of the C2.4 flare. This brought the system to a magnetic
configuration where the establishment of the second triggering event was
favorable. The second triggering episode occurred ~17 minutes later, during the
early phase of the M9.0 flare, evidenced by the further rise of the filament
and successful ejection. The second trigger is followed by a flare precursor
phase, characterized by non-thermal emission and the sequential formation of a
hot channel as shown by the SDO/AIA DEM (differential emission measure) maps,
the RHESSI X-ray images and spectra. These observations are suggestive of
magnetic reconnection and particle acceleration that can explain the precursor
phase and can be directly related to the formation of the hot channel. We
discuss on the triggering mechanisms, their implications during the early and
precursor phases and highlight the importance of early activities and preceding
small confined flares to understand the initiation of large eruptive flares.
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