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Title: Multichord optical interferometry of FRX-L's field reversed configuration

Abstract

A 0.633 {mu}m laser interferometer provides detailed time resolved information about the spatial distribution of the plasma density of field reversed configurations (FRC's) produced by the FRX-L experiment at Los Alamos National Laboratory. This experiment is an effort to produce a magnetized plasma with closed field lines suitable for compression by a solid metal liner imploded by the Shiva Star capacitor bank at the Air Force Research Laboratory. The interferometer probes a fanned array of eight chords through the FRC midplane, measuring the line integrated free electron density via its effect on optical phase shift relative to eight reference beams as a function of time. The reference beams are given nominally identical optical paths, except that they are folded for compactness and given an 80 MHz higher optical frequency by use of a Bragg cell beam splitter. After the beams are recombined, interference results in 80 MHz electromagnetic beat waves with dynamic phase shifts equal to those of the corresponding optical probes. Quadrature mixing of the electronically monitored light is then performed with rf components. Noteworthy features of the interferometer's design are the unique compact folding scheme of the reference paths, inclusion of a fused quartz tube in the referencemore » path similar to that of the FRC's vacuum vessel to compensate for cylindrical lensing, and transmission of the interfering light via optical fibers to a rf shielded room for processing. Extraneous contributions to the phase shift due to vibration resulting from the system's pulsed magnetic field, and dynamic refractive changes in or near the fused quartz tube wall (possibly due to radiation heating) are corrected for.« less

Authors:
; ; ; ; ; ; ;  [1]
  1. Air Force Research Laboratory, Directed Energy Directorate, Kirtland AFB, New Mexico 87117 (United States)
Publication Date:
OSTI Identifier:
20861167
Resource Type:
Journal Article
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 77; Journal Issue: 10; Other Information: DOI: 10.1063/1.2354568; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0034-6748
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; BEAM SPLITTING; BEAMS; CAPACITORS; CYLINDRICAL CONFIGURATION; FIELD-REVERSED THETA PINCH DEVICES; INTERFEROMETERS; INTERFEROMETRY; MHZ RANGE; OPTICAL FIBERS; PHASE SHIFT; PLASMA DENSITY; PLASMA DIAGNOSTICS; QUARTZ; RADIATION HEATING; REVERSE-FIELD PINCH; REVERSED-FIELD PINCH DEVICES; SPATIAL DISTRIBUTION; TIME RESOLUTION; VISIBLE RADIATION

Citation Formats

Ruden, E L, Zhang, Shouyin, Wurden, G A, Intrator, T P, Renneke, R, Waganaar, W J, Analla, F T, Grabowski, T C, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, and Science Applications International Corporation, Albuquerque, New Mexico 87106. Multichord optical interferometry of FRX-L's field reversed configuration. United States: N. p., 2006. Web. doi:10.1063/1.2354568.
Ruden, E L, Zhang, Shouyin, Wurden, G A, Intrator, T P, Renneke, R, Waganaar, W J, Analla, F T, Grabowski, T C, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, & Science Applications International Corporation, Albuquerque, New Mexico 87106. Multichord optical interferometry of FRX-L's field reversed configuration. United States. https://doi.org/10.1063/1.2354568
Ruden, E L, Zhang, Shouyin, Wurden, G A, Intrator, T P, Renneke, R, Waganaar, W J, Analla, F T, Grabowski, T C, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, and Science Applications International Corporation, Albuquerque, New Mexico 87106. 2006. "Multichord optical interferometry of FRX-L's field reversed configuration". United States. https://doi.org/10.1063/1.2354568.
@article{osti_20861167,
title = {Multichord optical interferometry of FRX-L's field reversed configuration},
author = {Ruden, E L and Zhang, Shouyin and Wurden, G A and Intrator, T P and Renneke, R and Waganaar, W J and Analla, F T and Grabowski, T C and Los Alamos National Laboratory, Los Alamos, New Mexico 87545 and Science Applications International Corporation, Albuquerque, New Mexico 87106},
abstractNote = {A 0.633 {mu}m laser interferometer provides detailed time resolved information about the spatial distribution of the plasma density of field reversed configurations (FRC's) produced by the FRX-L experiment at Los Alamos National Laboratory. This experiment is an effort to produce a magnetized plasma with closed field lines suitable for compression by a solid metal liner imploded by the Shiva Star capacitor bank at the Air Force Research Laboratory. The interferometer probes a fanned array of eight chords through the FRC midplane, measuring the line integrated free electron density via its effect on optical phase shift relative to eight reference beams as a function of time. The reference beams are given nominally identical optical paths, except that they are folded for compactness and given an 80 MHz higher optical frequency by use of a Bragg cell beam splitter. After the beams are recombined, interference results in 80 MHz electromagnetic beat waves with dynamic phase shifts equal to those of the corresponding optical probes. Quadrature mixing of the electronically monitored light is then performed with rf components. Noteworthy features of the interferometer's design are the unique compact folding scheme of the reference paths, inclusion of a fused quartz tube in the reference path similar to that of the FRC's vacuum vessel to compensate for cylindrical lensing, and transmission of the interfering light via optical fibers to a rf shielded room for processing. Extraneous contributions to the phase shift due to vibration resulting from the system's pulsed magnetic field, and dynamic refractive changes in or near the fused quartz tube wall (possibly due to radiation heating) are corrected for.},
doi = {10.1063/1.2354568},
url = {https://www.osti.gov/biblio/20861167}, journal = {Review of Scientific Instruments},
issn = {0034-6748},
number = 10,
volume = 77,
place = {United States},
year = {Sun Oct 15 00:00:00 EDT 2006},
month = {Sun Oct 15 00:00:00 EDT 2006}
}