paper

Onset of Magnetic Explosion in Solar Coronal Jets in Quiet Regions on the Central Disk

arXiv:2006.04253 · doi:10.3847/1538-4357/ab88ce

Abstract

We examine the initiation of 10 coronal jet eruptions in quiet regions on the central disk, thereby avoiding near-limb spicule-forest obscuration of the slow-rise onset of the minifilament eruption. From the SDO/AIA 171A 12-second-cadence movie of each eruption, we (1) find and compare the start times of the minifilament's slow rise, the jet-base bright point, the jet-base interior brightening, and the jet spire, and (2) measure the minifilament's speed at the start and end of its slow rise. From (a) these data, (b) prior observations showing that each eruption was triggered by magnetic flux cancelation under the minifilament, and (c) the breakout-reconnection current sheet observed in one eruption, we confirm that quiet-region jet-making minifilament eruptions are miniature versions of CME-making filament eruptions, and surmise that in most quiet region jets: (1) the eruption starts before runaway reconnection starts, (2) runaway reconnection does not start until the slow-rise speed is at least about 1 km/s, and (3) at and before eruption onset there is no current sheet of appreciable extent. We therefore expect: (i) many CME-making filament eruptions are triggered by flux cancelation under the filament, (ii) emerging bipoles seldom, if ever, directly drive jet production because the emergence is seldom, if ever, fast enough, and (iii) at a separatrix or quasi-separatrix in any astrophysical setting of magnetic field in low-beta plasma, a current sheet of appreciable extent can be built only dynamically by a magnetohydrodynamic convulsion of the field, not by quasi-static gradual converging of the field.

20 pages, 11 figures and 1 table; Published in ApJ

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