Wave-Excited Anomalous Diffusion in a Fully Ionized Magnetoplasma

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Abstract
The transverse diffusion coefficient D⊥ of a fully ionized plasma in a Q machine was observed to depend on the frequency and amplitude of low-frequency (kilocycle) waves. These waves, observed with a floating Langmuir probe and spectrum analyzer, could be impressed on the plasma (1) by a weak electron beam injected along the plasma axis, (2) by applying an ac signal of appropriate frequency to a plate at one end of the plasma, or (3) were found to occur naturally. D⊥ was determined from the radial profile of potassium plasma pulses. In all cases, D⊥ was strongly influenced by the amplitude of the low-frequency components of the spectrum and was observed to be proportional to the rms power of the fluctuations. The impedance of the plasma as a function of the impressed ac signal showed minima at frequencies close to that of the ``drift instability,'' where the value of D⊥ exhibited strong maxima.