Duncan H Mackay, Mr. - Ph.D.
University of St. Andrews
http://www.solar.mcs.st-and.ac.uk/~duncan
       
       
Session 3 - Speaker

Modelling the Hemispheric Pattern of Filaments

D.H.Mackay: Univ of St. Andrews; A. A van Ballegooijen, CFA Harvard
       

New results in modelling the hemispheric pattern of solar filaments through magnetic flux transport and magnetofrictional simulations are presented. The simulations consider for the first time what type of chirality forms along the Polarity Inversion Line (PIL) lying in between two magnetic bipoles as they interact. Such interactions are important for filament formation as observations by Tang 1987 show that the majority of filaments form in between bipolar regions rather than within a single magnetic bipole. The results clearly demonstrate for the first time not only the origin of the dominant hemispheric pattern but also why exceptions to it may occur. The dominant hemispheric pattern may be attributed to the dominant range of bipole tilt angles and helicities in each hemisphere (Wang 1989,Pevstov 1995). Exceptions to the hemispheric pattern are found to only occur in cases of no initial helicity or for helicity of the minority type in each hemisphere when large positive bipole tilt angles ($\\\\alpha > 20^\\\\circ$) are used. As the simulations show a clear dependence of the hemispheric pattern and it\\\'s exceptions on observational quantities this may be used to check the validity of the results.