Back Reaction to the Spectrum of Magnetic Field in the Kinetic Dynamo Theory --- Modified Kulsrud and Anderson Equation ---

Abstract

We take account of the lowest order back reaction on the fluid and modify the Kulsrud and Anderson equation ${\partial }_t{\mathcal{E}}_M=2\gamma {\mathcal{E}}_M$ obtained in the kinetic dynamo theory, where ${\mathcal{E}}_M$ is the energy density of the magnetic field. Furthermore, we apply our present result to some astrophysical stages where the magnetic field is expected to be amplified by the dynamo mechanism.

Comments: 9 pages, LaTex, to appear in Prog. Theor. Phys