Implosion and Oscillation
| Nugget | |
|---|---|
| Number: | 204 |
| 1st Author: | Paulo Simões |
| 2nd Author: | Hugh Hudson |
| Published: | July 1, 2013 |
| Next Nugget: | Acceleration region of a flare |
| Previous Nugget: | Minoflares |
Introduction
We have many examples now of contracting motions at or before the impulsive phase of a solar flare (see, for example, Ref. [1], for one of the first reports, and an earlier Nugget.) Such an implosion is consistent with the idea of conservation of energy, since flare structures are basically volumes of almost pure magnetism (the plasma beta in the preflare corona is very low), and this implies that the energy storage can be represented by the volume integral of B2 as a first approximation. So, to release energy, the volume must shrink at the same time - hence a magnetic implosion. The magnetic structure of a flare also can support oscillatory motions, and these can be excited as a simple mechanical response to the implosion. Another earlier Nugget reports such pulsations detectable even at gamma-ray energies.
This Nugget reports a particularly clear example of implosion and oscillation in flare SOL2012-03-09 (M6.4), observed well by many observatories. This flare revealed new characteristics of the development of the implosion, and of the nature of the resulting oscillations. We take the opportunity below to speculate a little on the consequences of these newly found properties.
