RELAXATION OF NUCLEAR-SPIN IN ATOMIC-HYDROGEN DUE TO LONG-RANGE ORBITAL CURRENTS IN METAL WALLS

Thermal current fluctuations in bulk metal produce a fluctuating magnetic field that extends outside the metal's surface. We find that its spectral density <H(z)2>(omega) as a function of distance from the surface decays as ln(z) at distances less than the mean free path of the electrons in the metal and as 1/z at large z. We evaluate the nuclear-spin relaxation rate due to these fluctuations. We apply our model to the one-body surface relaxation rate of atomic hydrogen. We find the relaxation time to be of the order of 10(3) s at a temperature of 1 K. A possible relaxation mechanism due to electric-field fluctuations, which may also be applicable to cells with insulating walls, is discussed.