The solar wind as a plasma sheath problem

The Q-machine device has a heated surface that emits plasma and a sheath is formed at the surface that accelerates ions to the Bohm speed, retards electrons, and equalizes the downstream densities of electrons and ions. The usual mathematical description of the sheath could be recast in spherical coordinates for an attempted description of the solar wind; however, there is no clearly-defined starting radius. A spherical model is developed with kinetic ions and both "hot" and "cold" fluid electrons with the three population densities and the ion speed taken from satellite observations at 1 AU. This model is integrated "backwards" from the Earth sunward and a strong electric field accelerating ions is found in the coronal region at about 0.03 AU. The equations of motion include the drag exerted by the ions on the cold electrons.