Drift ordered short mean free path closure
  The complete short mean free path description of magnetized plasma in the drift ordering has recently been derived. The results correct the previous expressions for the ion pressure anisotropy (or parallel ion viscosity) and the perpendicular ion viscosity - the ion gyro-viscosity is unchanged. In addition, the electron problem is solved for the first time to obtain the electron pressure anisotropy (parallel electron viscosity) and the electron gyro-viscosity - the perpendicular electron viscosity is negligible. The results have been used to obtain a reduced fluid description appropriate to the edge of a tokamak. In addition, the complete description has been used to evaluate the radial transport of toroidal angular momentum that determines the radial electric field and flows in a tokamak. 
Peter J. Catto, Andrei N. Simakov