skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Preliminary design overview and performance assessment of the ITER low-field side reflectometer

Journal Article · · Nuclear Fusion

The design of the ITER low-field side reflectometer (LFSR) has matured to a complete end-to-end preliminary design. LFSR will supply three key plasma measurements: (1) electron density profile, (2) electron density fluctuations, and (3) poloidal rotation. Simultaneous measurements of the three quantities are enabled by an array of six monostatic antennas which inject from an equatorial port on the outboard side of the ITER vessel. Low-loss transmission lines, consisting of corrugated, overmoded waveguide and miter bends, transmit the 30–165 GHz, O- and X-mode signals to and from the ITER plasma. Integrated transmission-line components serve a range of purposes, such as protection from high-power stray radiofrequency radiation, accommodation of transmission-line displacement, and simultaneous measurement of reference and plasma phases during the discharge. Broadband transmission signals are realized by full-band microwave transceivers combined with quasi-optical multiplexing. A field-programmable gate array (FPGA) processor demodulates the profile reflectometer signals, enabling real-time density profile measurements for plasma control system feedback. A full-scale transmission line test facility provides an integrated environment to assess the performance of critical LFSR components. Theoretical modeling together with insertion loss measurements provide the basis for a comprehensive power budget, which accounts for transmitted output power, transmission-line losses, antenna coupling, and plasma effects. Results indicate that high signal-to-noise ratios are achievable with the current design. A synthetic reflectometer model, using real design parameters and baseline ITER profiles, has been developed to estimate the return signal. With evolving microwave and data acquisition technologies, full-band, ultrafast sweeps (<1 μs) will be realizable for ITER.

Research Organization:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
AC02-09CH11466
OSTI ID:
1603944
Journal Information:
Nuclear Fusion, Vol. 60, Issue 6; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 5 works
Citation information provided by
Web of Science

References (29)

New reflectometer design for density profile measurements on JET journal October 2006
Microwave reflectometry diagnostic for density profile and fluctuation measurements on ASDEX Upgrade journal January 1999
Performance and data analysis aspects of the new DIII-D monostatic profile reflectometer system journal November 2014
Gyrotron internal mode converter reflector shaping from measured field intensity journal April 1999
HE 11 mitre bends and gaps in a circular corrugated waveguide journal October 1994
Phase retrieval of gyrotron beams based on irradiance moments journal June 2002
Comments on ‘‘Relativistic effects on microwave reflectometry’’ [Phys. Fluids B 4, 3460 (1992)] journal August 1993
Two-dimensional simulations of correlation reflectometry in fusion plasmas journal January 2002
X ‐mode broadband reflectometric density profile measurements on DIII‐D journal October 1990
Antenna-plasma coupling calculations for the ITER low-field side reflectometer journal September 2018
Ultrafast broadband frequency modulation of a continuous wave reflectometry system to measure density profiles on ASDEX Upgrade journal December 1996
1 μ s broadband frequency sweeping reflectometry for plasma density and fluctuation profile measurements journal November 2017
New millimeter-wave access for JET reflectometry and ECE journal November 2005
Ultrafast frequency sweep heterodyne reflectometer on the Tore Supra tokamak journal January 2000
X -mode heterodyne reflectometer for edge density profile measurements on Tore Supra journal January 2001
Tests of a full-scale ITER toroidal interferometer and polarimeter (TIP) prototype on the DIII-D tokamak (invited) journal October 2018
3D Full-Wave Simulations of Reflectometry
  • Valeo, E. J.; Kramer, G. J.; Nazikian, R.
  • RADIO FREQUENCY POWER IN PLASMAS: Proceedings of the 18th Topical Conference, AIP Conference Proceedings https://doi.org/10.1063/1.3273835
conference January 2009
Multiband reflectometry system for density profile measurement with high temporal resolution on JET tokamak journal October 2010
Relativistic effects on microwave reflectometry journal October 1992
Fast sweeping reflectometry upgrade on Tore Supra journal October 2010
Performance of the microwave reflectometry diagnostic for density profile measurements on ASDEX Upgrade journal January 2001
A calibration method for lateral forces for use with colloidal probe force microscopy cantilevers journal January 2008
Advances of the density profile reflectometry on TORE SUPRA journal March 2003
2D reflectometer modelling for optimizing the ITER low-field side X-mode reflectometer system journal August 2006
High-resolution dual-polarization frequency modulated reflectometer density profile measurements on DIII-D journal October 2004
A dual source D-band reflectometer for density profile and fluctuations measurements in Tore-Supra journal August 2006
Turbulence correlation properties measured with ultrafast sweeping reflectometry on Tore Supra journal November 2013
A free-standing wire scattering technique to monitor calibration variations of the DIII-D density profile reflectometer journal October 2018
Tests of a two-color interferometer and polarimeter for ITER density measurements journal October 2017

Similar Records

Performance demonstration of vacuum microwave components critical for the operation of the ITER low-field side reflectometer
Journal Article · Tue Mar 09 00:00:00 EST 2021 · Review of Scientific Instruments · OSTI ID:1603944

Performance and data analysis aspects of the new DIII-D monostatic profile reflectometer system
Journal Article · Thu Aug 07 00:00:00 EDT 2014 · Review of Scientific Instruments · OSTI ID:1603944

Performance and data analysis aspects of the new DIII-D monostatic profile reflectometer system
Journal Article · Sat Nov 15 00:00:00 EST 2014 · Review of Scientific Instruments · OSTI ID:1603944