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Tests of a full-scale ITER toroidal interferometer and polarimeter (TIP) prototype on the DIII-D tokamak (invited)

Journal Article · · Review of Scientific Instruments
DOI:https://doi.org/10.1063/1.5037461· OSTI ID:1609188
 [1];  [2];  [3];  [4];  [2];  [3];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [5];  [5];  [5];  [6];  [2];  [7] more »;  [8];  [6] « less
  1. General Atomics, San Diego, CA (United States); DOE/OSTI
  2. General Atomics, San Diego, CA (United States)
  3. Palomar Scientific Instruments, San Marcos, CA (United States)
  4. National Inst. for Fusion Science, Gifu (Japan)
  5. Univ. of California, Los Angeles, CA (United States)
  6. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  7. California State Univ., San Marcos, CA (United States)
  8. ITER Organization, Saint Paul Lez Durance Cedex (France)
+ Show Author Affiliations
A full-scale ITER toroidal interferometer and polarimeter (TIP) prototype, including an active feedback alignment system, has been installed and tested on the DIII-D tokamak. In the TIP prototype, a two-color interferometry measurement of line-integrated density is carried out at 10.59 μm and 5.22 μm using a CO2 and quantum cascade laser, respectively, while a separate polarimetry measurement of the plasma-induced Faraday effect is made at 10.59 μm. The TIP prototype is equipped with a piezo tip/tilt stage active feedback alignment system that minimizes noise in the measurement and keeps the diagnostic aligned throughout DIII-D discharges. The measured phase resolution for the polarimeter and interferometer is 0.05° (100 Hz bandwidth) and 1.9° (1 kHz bandwidth), respectively. Here, the corresponding line-integrated density resolution for the vibration-compensated interferometer is δnL = 1.5 × 1018 m-2, and the magnetic field-weighted line-integrated density from the polarimeter is δnBL = 1.5 × 1019 Tm-2. Both interferometer and polarimeter measurements during DIII-D discharges compare well with the expectations based on calculations using Thomson scattering measured density profiles and magnetic equilibrium reconstructions. Additionally, larger bandwidth interferometer measurements show that the diagnostic is a sensitive monitor of core density fluctuations with demonstrated measurements of Alfvén eigenmodes and tearing modes.
Research Organization:
General Atomics, San Diego, CA (United States); Princeton Univ., NJ (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
AC02-09CH11466; FC02-04ER54698
OSTI ID:
1609188
Alternate ID(s):
OSTI ID: 1459747
Journal Information:
Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 10 Vol. 89; ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English

References (12)

Real‐time, vibration‐compensated CO 2 interferometer operation on the DIII‐D tokamak journal July 1988
Dual CO 2 laser interferometer with a wavelength combination of 10.6 and 9.27 μm for electron density measurement on large tokamaks journal April 1996
Multichannel far-infrared polarimeter-interferometer system on the MST reversed field pinch journal January 2001
CO2 laser polarimeter for electron density profile measurement on the Large Helical Device journal May 2003
Laser Faraday rotation measurement of current density fluctuations and electromagnetic torque (invited) journal October 2004
Toroidal interferometer/polarimeter density measurement system on ITER journal October 2004
Fiber optic two-color vibration compensated interferometer for plasma density measurements journal October 2006
CO2 laser polarimeter for Faraday rotation measurements in the DIII-D tokamak journal October 2008
Conceptual design of the tangentially viewing combined interferometer-polarimeter for ITER density measurements journal April 2013
Reconstruction of current profile parameters and plasma shapes in tokamaks journal November 1985
Chapter 7: Diagnostics journal June 2007
Tests of a two-color interferometer and polarimeter for ITER density measurements journal October 2017

Cited By (2)

Innovations in Technology and Science R&D for ITER journal January 2019
A heterodyne dispersion interferometer for wide bandwidth density measurements on DIII-D journal October 2018

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Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
Faraday effect
instruments & instrumentation
interferometry
lasers
optical polarimetry
physics
plasma diagnostics
plasma waves
polarimeters
tokamaks