Time lag between flare activity and the solar cycle

M Temmer

Veronig, A., and Hanslmeier, A.

Recently, Wheatland and Litvinenko (2001) presented a model for the dynamic energy balance in the corona over the solar cycle that predicts that the magnetic free energy in the corona lags behind the variation in the energy supply to the system. We test this model by analyzing daily H$\\alpha$ (1955--2002), and soft X-ray (1976--2002) flare rates in comparison to daily sunspot relative numbers. A characteristic time lag ($10 \\lesssim \\tau \\lesssim 15$~months) between flare activity and sunspot activity is found in cycles 19, 21, and 23 but not in cycles 20 and 22, indicating a 22-year variation related to the magnetic cycle. Moreover, the phenomenon turns out to be more prominent for high-energetic flares. The investigation of solar activity separately for the northern and southern hemisphere enables us to exclude overlapping effects from the activity of both hemispheres and confirms the dynamic relevance of the delay phenomenon. The existence of a 22-year variation in the energy supply rate is evidenced by the empirical Gnevyshev-Ohl rule.