Rapid Electron-Density Oscillations on the Axis of a Theta Pinch

A detailed temporal history of the electron density on the axis of a theta pinch is presented. During the magnetic compression, oscillations are superimposed on the electron density. The amplitude of these oscillations is, under some conditions, as large as 50% of the maximum value attained in the pinched state. These density variations are ascribed to radial hydromagnetic oscillations. The electron density measurements were made by means of a spherical laser interferometer and these were correlated with electron density measurements using Stark broadening techniques.