Abstract:
We study the active region NOAA 10960, which produces two flare events
(B5.0, M8.9) on 04 June 2007. We find the observational signature of right
handed helical twists in the loop system associated with this active region. The
first B5.0 flare starts with the activation of helical twist showing ~ 3 turns.
However, after ~ 20 minutes another helical twist (with ~ 2 turns) appears,
which triggers M8.9 flare. Both helical structures were closely associated with
a small positive polarity sunspot in the AR. We interpret these observations
as evidence of kink instability, which triggers the recurrent solar flares.
