volume | PIER Journals

2018-04-27

Design and Development of Millimeter Wave Interferometer Circuit for Real-Time Measurement of Plasma Density

Praveen Kumar Atrey,

Dr. Praveen Kumar Atrey

Institute of Technology

Nirma University

India

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Dhaval A. Pujara,

Prof. Dhaval A. Pujara

Department of Electronics & Communications Engineering, Institute of Technology

Nirma University

India

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Subroto Mukherjee,

Dr. Subroto Mukherjee

Institute for Plasma Research

India

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Umesh Nagora,

Dr. Umesh Nagora

Institute for Plasma Research

India

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Praveenlal Edappala,

Dr. Praveenlal Edappala

Institute for Plasma Research

India

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Praveena Kumari,

Dr. Praveena Kumari

Institute for Plasma Research

India

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Rachana Rajpal

Dr. Rachana Rajpal

Institute for Plasma Research

India

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Progress In Electromagnetics Research M, Vol. 68, 1-10, 2018

doi:10.2528/PIERM18011502

Abstract

A 3-mm wave interferometer is designed and developed to measure the electron density online at the central chord of Aditya tokamak, unambiguously. The scheme used for this has the advantages in operating the interferometer without a source frequency modulation and easy data processing. The central chord of a 3-mm wave homodyne interferometer system is modified to make a quadrature circuit by using phase shifters and magic tees. This is used to produce the sine/cosine fringe signals. These outputs are amplified and converted into pulses and passed to wired logic up/down fringe counter. Digital synchronous logic circuit is implemented in a Complex Programmable Logic Device (CPLD), followed by digital to analog converter (DAC) and scaler which produces a voltage proportional to increase or decrease in plasma density in real time. The paper presents about this technique and test results of the fringe counter with artificial signals. The chord averaged plasma density n_e = 0.9 × 10¹³ cm^-3 is measured online at Aditya tokamak using this interferometer.

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Praveen Kumar Atrey, Dhaval A. Pujara, Subroto Mukherjee, Umesh Nagora, Praveenlal Edappala, Praveena Kumari, and Rachana Rajpal, "Design and Development of Millimeter Wave Interferometer Circuit for Real-Time Measurement of Plasma Density," Progress In Electromagnetics Research M, Vol. 68, 1-10, 2018.
doi:10.2528/PIERM18011502

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