Large-scale flows of collisionless plasmas along the magnetic lines of force: electric fields and currents parallel to the magnetic field, the stress tensor

The standard derivation of plasma equations for large-scale motion by expanding in the particle mass to charge ratio fails if the flow velocity along the magnetic lines of force (B-lines) exceeds a certain limit. Large-scale and fast flows of plasma along B-lines are associated with electric fields and currents with a component parallel to B. Off-diagonal terms in the pressure tensor matrix assume non-zero values dependent on geometry of the B-lines. The plasma equations are reduced to standard equations for large-scale plasma motions if the macroscopic velocity along the B-lines decreases toward the average particle velocity perpendicular to B. (Auth.)