Development of microwave plasma diagnostics for various plasma devices*

Plasmas are widely used in science and engineering, including magnetic confinement plasmas for nuclear fusion, plasmas for electric propulsion, and process plasmas for semiconductor manufacturing. However, few plasma diagnostic systems such as electron density and electron temperature are commercially available, and researchers are burdened with the burden of building their own measurement devices.

The author has developed a number of microwave and millimeter-wave plasma measurement devices, and is promoting their use in the various fields mentioned above. For example, microwave reflectometer and interferometer can measure electron density profile and fluctuation, electron cyclotron emission diagnostics can measure electron temperature and fluctuations. We have developed an extremely easy-to-use transmitter and receiver system using superheterodyne and frequency multiplication techniques, and applied them to many plasma device such as tokamak and helical plasma devices, linear plasma devices, Hall thrusters and RF plasma thrusters.

In this presentation, these microwave devices and its applications will be shown.