Sunspot groups are the main source of solar ﬂares, with the energy to power them being supplied by magnetic-ﬁeld evolution (e.g. ﬂux emergence or twisting/shearing). To date, few studies have investigated the statistical relation between sunspot-group evolution and ﬂaring, with none considering evolution in the McIntosh classiﬁcation scheme. Here we present a statistical analysis of sunspot groups from Solar Cycle 22, focusing on 24-hour changes in the three McIntosh classiﬁcation components. Evolution-dependent > C1.0, >M1.0, and > X1.0 ﬂaring rates are calculated, leading to the following results: (i) ﬂaring rates become increasingly higher for greater degrees of upward evolution through the McIntosh classes, with the opposite found for downward evolution; (ii) the highest ﬂaring rates are found for upward evolution from larger, more complex, classes (e.g. Zurich D- and E-classes evolving upward to F-class produce > C1.0 rates of 2.66 ± 0.28 and 2.31 ± 0.09 ﬂares per 24 hours, respectively); (iii) increasingly complex classes give higher rates for all ﬂare magnitudes, even when sunspot groups do not evolve over 24 hours. These results support the hypothesis that injection of magnetic energy by ﬂux emergence (i.e. increasing in Zurich or compactness classes) leads to a higher frequency and magnitude of ﬂaring.
|Early online date||27 Jun 2016|
|Publication status||Published - Aug 2016|