Density Distribution of Plasmas Resembling Dark Matter Halo Due to Ionization lag and Ambipolar Electric Field

Abstract

In a spherically symmetric plasma constrained by its own gravity, the ionization degree lags behind changes in temperature and density. The ambipolar electric field accelerates ions radially and cools electrons. Ions lose energy and angular momentum in collisions with low-temperature electrons. The angular momentum of ions decreases much faster than their energy in cycles. The trajectories of ions are close to radial, and the density distribution resembles pseudo-isothermal. The velocity distributions of baryons moving outward and inward in galaxies tend to approach independent Maxwell distributions. This characteristic suppresses small-angle scattering of ions, reducing the ion collision cross-section by three orders of magnitude. In the massive galaxies, baryons can replace all dark matter.