Low-Frequency Oscillations in a Potassium Plasma

Low-frequency oscillations (10–30 kc/sec) have been observed in thermal potassium plasmas, produced by surface ionization of potassium atoms on a hot tungsten plate. The oscillations are associated with the presence of an ion sheath near the tungsten plate and seem to be reasonably well described on the basis of a simple picture of ion waves propagating across the magnetic lines of force, in the presence of a density gradient.