Semi-Analytic Evaluation of the Electron Density Distribution of Tokamaks With Central Chord Microwave Interferometer

Document Type : Original Article

Author

Assistant Professor, Institute of Plasma and Nuclear Fusion, Institute of Nuclear Science and Technology, Tehran, Iran

Abstract

Microwave interferometry which is being used in various tokamaks in the world, is considered as one of the most reliable techniques for electron density measurement of tokamaks. The simplest type of homodyne microwave interferometers is the single channel or central-chord interferometer which measures the line integrated electron density along the longest chord of the plasma cross section of the tokamak. One of the restrictions of        central-chord interferometers is that they cannot determine the spatial distribution of electron density. In this paper a semi-analytic approach based on phase difference analysis, is proposed for qualitative evaluation of electron distribution in tokamaks with central-chord interferometer. According to the suggested model, several density profiles are proposed to describe the electron distribution. It is found that in high frequency ranges the trapezoidal distribution can provide a better qualitative estimation of the spatial distribution of electron density in tokomaks. The proposed model can be used as a primary analysis of the spatial distribution of electron density along with complimentary techniques such as the microwave reflectometry and multi-channel interferometers.

Keywords


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