[PEM19-P07] Magnetic Flux Cancelation as the Buildup and Trigger Mechanism for CME-Producing Eruptions in two Small Active Regions
Keywords:Sun: Filaments, prominences, Sun: Magnetic fields, Sun: Flares, Sun: CMEs
We follow two small, magnetically isolated CME-producing solar active regions (ARs) from
the time of their emergence until several days later, when their core regions erupt to produce
the CMEs. In both cases, magnetograms show: (a) following an initial period where the poles
of the emerging regions separate from each other, the poles then reverse direction and start
to retract inward; (b) during the retraction period, flux cancelation occurs along the main neutral
line of the regions, (c) this cancelation builds the sheared core field/flux rope that eventually
erupts to make the CME. In the two cases, respectively 30% and 50% of the maximum flux of
the region cancels prior to the eruption. Recent studies indicate that solar coronal jets
frequently result from small-scale filaments eruptions (Sterling et al. 2015), with those
“minifilament” eruptions also being built up and triggered by cancelation of magnetic flux
(Panesar et al. 2016). Together, the small-AR eruptions here and the coronal jet results
suggest that isolated bipolar regions tend to erupt when some threshold fraction, perhaps
in the range of 50%, of the region’s maximum flux has canceled. Our observed erupting
filaments/flux ropes form at sites of flux cancelation, in agreement with previous observations.
Thus, the recent finding that minifilaments that erupt to form jets also form via flux cancelation
is further evidence that minifilaments are small-scale versions of the long-studied full-sized
filaments. (Details are in Sterling et al. 2018, ApJ, 864, 68.) This work was supported by
the NASA HGI Program, and the NASA/MSFC NPP program.
the time of their emergence until several days later, when their core regions erupt to produce
the CMEs. In both cases, magnetograms show: (a) following an initial period where the poles
of the emerging regions separate from each other, the poles then reverse direction and start
to retract inward; (b) during the retraction period, flux cancelation occurs along the main neutral
line of the regions, (c) this cancelation builds the sheared core field/flux rope that eventually
erupts to make the CME. In the two cases, respectively 30% and 50% of the maximum flux of
the region cancels prior to the eruption. Recent studies indicate that solar coronal jets
frequently result from small-scale filaments eruptions (Sterling et al. 2015), with those
“minifilament” eruptions also being built up and triggered by cancelation of magnetic flux
(Panesar et al. 2016). Together, the small-AR eruptions here and the coronal jet results
suggest that isolated bipolar regions tend to erupt when some threshold fraction, perhaps
in the range of 50%, of the region’s maximum flux has canceled. Our observed erupting
filaments/flux ropes form at sites of flux cancelation, in agreement with previous observations.
Thus, the recent finding that minifilaments that erupt to form jets also form via flux cancelation
is further evidence that minifilaments are small-scale versions of the long-studied full-sized
filaments. (Details are in Sterling et al. 2018, ApJ, 864, 68.) This work was supported by
the NASA HGI Program, and the NASA/MSFC NPP program.