The hemispheric sign rule of current helicity during the rising phase of cycle 23

Abstract

We compute the signs of two different current helicity parameters (i.e., αbest andH c) for 87 active regions during the rise of cycle 23 The results indicate that 59% of the active regions in the northern hemisphere have negative αbest and 65% in the southern hemisphere have positive. This is consistent with that of the cycle 22. However, the helicity parameterH cshows a weaker opposite hemispheric preference in the new solar cycle. Possible reasons are discussed.