Some Experimental Observations of the Attenuation of Alfven Waves in a Laboratory Plasma

Abstract

An experiment is described in which the velocity and attenuation of torsional, azimuthally symmetric, hydromagnetic waves are measured in a hydrogenous plasma, from low frequencies where ion-neutral collisions are unimportant to the wave damping, to frequencies where such collisions profoundly affect the damping. A theory including both ion-electron and ion-neutral collisions is outlined, and the attenuation results are compared with the theoretical values. An estimate is made, from the frequency dependence of the attenuation, of the hydrogen ion-atom collision cross section for momentum transfer.