Mean maganetic field in renovating random flow
Abstract
An integral equation is derived for a mean magnetic field in a random velocity field that renovates after a characteristic time τ. It is shown that in two cases, i.e. when (1) the correlation time is short, τ very low l/v_{0} (where l and v_{0} are the characteristic scale and velocity), and (2) for long wave components of the field, k^{1} very large v_{0}τ, the equation is reduced to the differential one, whose form has first been given by Steenbeck, Krause and Rädler. Expressions for the equation coefficients are obtained in the two above cases. In a general case the integral equation cannot be reduced to the differential one although its spectral properties are close in a certain sense to those of the SKRequation. There are differences, however, that are shown on the example of the Gaussian distribution of particles moving along random paths.
 Publication:

Astronomische Nachrichten
 Pub Date:
 1984
 DOI:
 10.1002/asna.2113050305
 Bibcode:
 1984AN....305..119D
 Keywords:

 Astrophysics;
 Flow Velocity;
 Magnetic Fields;
 Random Processes;
 Approximation;
 Integral Equations;
 Planetary Magnetic Fields;
 Reynolds Number;
 Solar Magnetic Field;
 Stellar Magnetic Fields;
 Velocity Distribution;
 Astrophysics