BothEmden's/sup1 old hydrodynamic solar theory and the more modern thermo-hydrodynamical solar theory due to Bjerknes/sup2 lead to a higher temperature at the poles than at the equator of the sun. Bjerknes's theory is, ...

In 1932, Bartels put forward the hypothesis that moderate geomagnetic storms with gradual commencements were associated with certain active regions on the sun which he called M-regions. Solar and geomagnetic studies in ...