Sensitive measurement of phase shifts due to the ac Stark effect in a Ca optical Ramsey interferometer.

Fluctuating anisotropic electric fields in the anode plasma of a high-power ion diode are investigated as a function of time throughout the 100-ns-long voltage pulse by polarization spectroscopy of hydrogen lines. The H α and H β spectral profiles observed for different polarizations and lines of sight are compared'to calculations, based on the quasistatic approximation, of the emission pattern resulting from the combined influence of the ionic and the turbulent electric fields. Assuming one-dimensional Rayleigh distributions for the turbulent field amplitudes, the difference between the linewidths observed for orthogonal polarizations yields mean amplitudes ≥5 kV/cm for the turbulent fields