Origin of the solar wind: Theory

A theory is presented for the origin of the solar wind, which is based on t he behavior of the magnetic field of the Sun. The magnetic field of the Sun can be considered as having two distinct components: Open magnetic flux in which the field lines remain attached to the Sun and are dragged outward i nto the heliosphere with the solar wind. Closed magnetic flux in which the field remains entirely attached to the Sun, and forms loops and active regi ons in the solar corona. It is argued that the total open flux should tend to be constant in time, since it can be destroyed only if open flux of oppo site polarity reconnect, a process that may be unlikely since the open flux is ordered into large-scale regions of uniform polarity. The behavior of o pen flux is thus governed by its motion on the solar surface. The motion ma y be due primarily to a diffusive process that results from open field line s reconnecting with randomly oriented closed loops, and also due to the usu al convective motions on the solar surface such as differential rotation. T he diffusion process needs to be described by a diffusion equation appropri ate for transport by an external medium, which is different from the usual diffusion coefficient used in energetic particle transport. The loops requi red for the diffusion have been identified in recent observations of the Su n, and have properties, both in size and composition, consistent with their use in the model. The diffusive process, in which reconnection occurs betw een open field lines and loops, is responsible for the input of mass and en ergy into the solar wind.