Space and time resolved measurements in magnetically confined plasmas using a heavy ion beam probe

A heavy ion beam probe provides space and time resolved measurements of plasma density, space potential, electron temperature, and current density in energetic, magnetically confined plasmas. A new dual beam technique has been developed to separate density and electron temperature measurements by probing the plasma with two different species. An extension of this technique has been used in conjunction with a feedback controlled, electrostatic energy analyzer to yield the only direct, absolute measurement of plasma space potential. Calibration of the frequency response of the analyzer/detector system has permitted direct measurements of the amplitude and phase of both density and space potential oscillations associated with plasma instabilities.