The Sun's magnetic cycle: observations and modeling: The hydromagnetic dynamo

Abstract

The Sun displays a plethora of visually awe-inspiring phenomena including flares, prominences, sunspots, corona, CMEs, and uncountable others. The solar magnetic field controls the dynamics and topology of all these, as well as the solar wind. Since the solar magnetic field affects the interplanetary space around the Earth in a profound manner, it is absolutely essential that we develop a comprehensive understanding of the generation and manifestation of the magnetic fields of the Sun. On the solar surface, where we are first able to measure it, the magnetism appears to be organized into different spatial scales ranging from intergranular boundaries ∼300 km to the size of the Sun. Most prominent are the strongly magnetized regions appearing as dark sunspots on its visible surface. The number and area of these spots are modulated on a time scale of approximately 11 years. We will now explore the origins of this magnetic field and how it lives up to the sobriquet – the nature's third cycle.