Plasma diffusion in a magnetic field due to coulomb collisions

The diffusion of a decaying helium plasma has been studied by a v.h.f. method. The investigations were carried out at parameters for which the diffusion flux across the magnetic field was due to electron-ion collisions. The measured diffusion coefficients in magnetic fields of 700 to 800 Oe are in accordance with those derived on the basis of the classical theory of binary Coulomb collisions. In the range of magnetic fields from 1000 to 5000 Oe a considerable deviation from the theory is observed, the diffusion coefficient being proportional to 1/H. The asymptotic solution is found for the diffusion equation which describes a decaying fully ionized plasma in the case of axial symmetry.