DIFFUSION OF IONS IN A PLASMA ACROSS A MAGNETIC FIELD

A theoretical and experimental investigation of the coefficient for diffusion of ions across a magnetic field is described. The resultant diffusion coefficient is found to vary inversely as the square of the magnetic field strength, in accord with the usual collison-diffusion theory. The magnitude of the coefficient is much larger (x700) than the coefficient predicted by the usual ambipolar diffusion theory. This discrepancy is resolved by showing that diffusfon across a magnetic field is not ambipolar in character in most are experiments. The final experimental and theoretical values are in good agr- eement, and it is unecessary to postulate any additional diffusion mechanisms, such as plasma oscillations. (auth)