A Two-Level Solar Dynamo Based on Solar Activity, Convection, and Differential Rotation

Abstract

In orthodox dynamo theory (Stix, 1976), the two basic processes, generation of toroidal from poloidal field and conversion of toroidal into reversed poloidal field, are both located in the high β regime convection zone. Generation requires that regime, since its function demands it be driven by mechanical forces. But the function and therefore the operating requirements of conversion are entirely different, and there seems to be no à priori reason, other than historical tradition coupled with failure to recognize those differences, for the assumption that conversion must also operate there. Conversion transforms the topological structure of generated flux by altering the field line connectivity, so that the principal task performed is reconnection. Reconnection is a spontaneous process which must compress and accelerate plasma if any is present. Obviously it must perform much more work in the high β convection zone than in the low β solar atmosphere. It seems natural, therefore, to expect the reconnection aspect of conversion to be located there, where the least work needs to be performed. To transfer the generated flux there, we may add to conversion another spontaneous process: eruption of bipolar structure (Parker, 1955). To transfer the reconnected flux back down, we add to generation another mechanically driven process called topological pumping (Drobyshevski and Yuferev, 1974). Topological pumping depends on the diamagnetic effect of eddy-motion (Wiess, 1966), the kind possessed by supergranulation: 3-dimensional arrangement of isolated rising plumes, surrounded by a continuous network of descending sheet-like flow. In the two-level dynamo presented here, conversion may be observed directly, since we expect it to express itself in terms of all forms of solar activity: sunspots, flares, faculae, filaments, coronal structures including coronal holes, etc., and their organization and evolution in a “solar meteorology”. It is clearly important to investigate a model that thus unites the two disciplines of solar activity and dynamo theory. Each strengthens the other and brings a greater unity to solar physics.