Noise-free neutral sheets

The rate of reconnection in the geomagnetic tail presents a quantitative problem. If this rate is to be accounted for by noise, strong turbulence is required. Here noise is neglected and simple discussions of particle motion, velocity distributions and stresses suggest an alternative solution. Electron trajectories are Speiser type and 'residence time' is the crucial quantity. Velocity distributions are skewed, exhibiting electron viscosity. It now seems appropriate to attempt two fluid modelling with anisotropic pressure. The quantitative problem of the tail needs a small spatial scale for the fiels and the tearing mode may be a means to this end. (author). 8 refs.; 1 fig