Authors: Mausumi Dikpati

Over the past decade, substantial progress in modeling of solar dynamo has been made, which has taken us beyond the simulation of ‘butterfly diagram’. Particular advancement has been the recent efforts of establishing synergies between kinematic models and full 3D-MHD models, the former having the ability of scale separations between small-scale turbulence and large-scale dynamics and full-3D-MHD models, and the latter can include all MHD processes. Many breakthroughs came up from such an enormous step-forward, in the form of simulating buoyancy instability driven emergences of bipolar active regions, torsional oscillation patterns and extended solar cycles. A remaining task is simulating many longitude-dependent solar cycle features and eventually predicting them. Note that predicting space weather is challenging because the active regions do not appear at one longitude always and hence there isn’t a perfect periodicity at which the space weather would occur, neither they appear uniformly distributed over the photosphere. Surface active regions show a certain spatio-temporal distribution, which has systematic as well as random components, sometimes the former is substantial than the latter. If dynamos generate predominantly axisymmetric spot-producing toroidal fields, what causes their longitude dependence, eventually rendering the solar cycle to manifest its features in 3D? Here I will argue how the tachocline plays crucial roles in producing 3D spatio-temporal evolutionary patterns of solar cycle features.