Multichannel interferometer/polarimeter system for the RTP tokamak

Journal Article · Mon Oct 01 04:00:00 EDT 1990 · Review of Scientific Instruments; (USA)

DOI:https://doi.org/10.1063/1.1141814· OSTI ID:6135148

van Lammeren, A C.A.P.; Kim, S K; Donne, A J.H. ^[1]

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1. FOM-Instituut voor Plasmafysica Rijnhuizen, Associatie EURATOM-FOM, 3430 BE Nieuwegein (The Netherlands)

A nine-channel interferometer/polarimeter system is designed for the RTP tokamak (Rijnhuizen Tokamak Project, {ital a} =0.16 m, {ital R} =0.72 m, {ital B}{sub {ital T}} =2.5 T, {ital I}{sub {ital p}} {le} 200 kA, and plasma pulse duration 200 ms). A CO{sub 2}-pumped dual-cavity FIR laser system is used to obtain two FIR laser beams of {lambda} =432 {mu}m with a frequency difference of 1 MHz. The FIR beams are expanded by a set of parabolic mirrors. Corner-cube mixers with Schottky diodes are used as detectors. The mixers are mounted on a linear rail system, such that their positions can be easily changed. The interferometer can be operated with a maximum of 19 channels, and will be extended with a polarimeter to measure the poloidal magnetic field distribution. It will be tried to increase the accuracy of the polarimeter by modulating the polarization of the incoming beam. A scheme for polarization modulation which is based on the idea of Dodel and Kunz will be presented in this paper. This scheme has the advantage that only one set of detectors is needed to measure the electron density and current density. The complete system will be presented along with some pilot experiments concerning the polarization modulation.

• OSTI ID: 6135148
• Journal Information: Review of Scientific Instruments; (USA), Journal Name: Review of Scientific Instruments; (USA) Vol. 61:10; ISSN RSINA; ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102* -- Fusion Energy-- Plasma Research-- Diagnostics
CLOSED PLASMA DEVICES
FARADAY EFFECT
INTERFEROMETERS
MAGNETIC FIELDS
MEASURING INSTRUMENTS
PLASMA DIAGNOSTICS
POLARIMETERS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES