On the explosive nature of auroral substorms and solar flares: The electric current approach

Abstract

Both auroral substorms and solar flares have explosive nature. Since both are mostly various manifestations of electromagnetic energy dissipation processes, it is basic to consider both phenomena as a chain of electromagnetic processes, which consists of a dynamo process as the power supply, power transmission and manifestations of dissipative processes (auroral substorms and solar flares)--the electric current approach. Based on this view, since both phenomena are powered by a dynamo and have an explosive component, they are likely to have the component directly driven (DD) by the dynamo and the component which results from the unloading (UL) process of accumulated energy (generated also by the dynamo). Thus, it is crucial to identify and distinguish the dynamo-produced power/energy/dissipation into two components in both morphology and theory. In this paper, since we have taken this approach for auroral substorms, we attempt to apply it for solar flares by adopting a photospheric dynamo theory by Lee et al. (1995) and Choe and Lee (1996a, 1996b); their dynamo process takes place on the photosphere under a magnetic arcade. It is shown that their dynamo can supply both the power and energy needed for flares, providing the arcade field-aligned currents for the two-ribbon Hα emission (DD) and the current loop along the dark filament above the arcade for the explosive process (UL).