Coronal Heating by Nanoflares and the Variability of the Occurence Frequency in Solar Flares



Abstract


It has been proposed that flares in the solar corona may well be a result of an internal Self - Organised Critical (SOC) process in active regions. We have developed a cellular automaton SOC model which simulates flaring activity extending over an active subflaring background. In the resulting frequency distributions we obtain two power laws. That of the weaker events is shorter and much steeper than that of the intermediate and large events. The flatter power law is in close agreement with observations of flares. Weaker events are responsible for the vast majority of energy released, providing a possible connection of nanoflares with coronal heating. Moreover, certain mechanisms cause the variability of the resulting indices, and may provide answers on the problem of the variability of flares' occurence frequency during solar cycle.

Subject Headings: Sun: activity - Sun: corona - Sun:flare-Sun: magnetic fields - Stars: activity - Stars: flare

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