28 citations · 99 across the 13 of their papers we have counts for
13 papers
Real-time steerable frequency-stepped Doppler Backscattering (DBS) System for local helicon wave electric field measurements on the DIII-D tokamak
S. Chowdhury, N. A. Crocker, W. A. Peebles +11
A new frequency-stepped Doppler backscattering (DBS) system has been integrated with a real-time steerable electron cyclotron heating launcher to probe local background turbulence…
ELM-free Enhanced Dα H-mode with Near Zero NBI Torque Injection in DIII-D Tokamak
T. Macwan, K. Barada, J. F. Parisi +11
Enhanced H-mode (EDA H-mode), an ELM-free H-mode regime, is explored in neutral beam heated, lower single null plasmas with near zero torque injection. This regime exhibits a…
A novel Doppler backscattering (DBS) system to simultaneously monitor radio frequency plasma fluctuations and low frequency turbulence
S. Chowdhury, N. A. Crocker, W. A. Peebles +6
A novel quadrature Doppler Backscattering (DBS) system has been developed and optimized for the E-band (60-90GHz) frequency range using either O-mode or X-mode polarization in DIII…
Effect of mismatch on Doppler backscattering in MAST and MAST-U plasmas
Valerian H. Hall-Chen, Felix I. Parra, Jon C. Hillesheim +14
The Doppler backscattering (DBS) diagnostic, also referred to as Doppler reflectometry, measures turbulent density fluctuations of intermediate length scales. However, when the bea…
Validating and optimising mismatch tolerance of Doppler backscattering measurements with the beam model
Valerian H. Hall-Chen, Julius Damba, Felix I. Parra +11
We use the beam model of Doppler backscattering (DBS), which was previously derived from beam tracing and the reciprocity theorem, to shed light on mismatch attenuation. This atten…
Observation of Long-Radial-Range-Correlation in Turbulence in High-Collisionality High-Confinement Fusion Plasmas
R. Hong, T. L. Rhodes, P. H. Diamond +6
We report on the observation of spatially asymmetric turbulent structures with a long radial correlation length in the core of high-collisionality H-mode plasmas on DIII-D tokamak.…
Ray-tracing Analysis for Cross-polarization Scattering Diagnostic on MAST-Upgrade Spherical Tokamak
R. Hong, T. L. Rhodes, G. Wang +1
A combined Doppler backscattering/cross-polarization scattering (DBS/CPS) system is being deployed on MAST-U, for simultaneous measurements of local density turbulence, turbulence…
Observation of quasi-coherent density fluctuation in scrape-off layer enhancing boundary transport in high-betaN hybrid plasmas on DIII-D
R. Hong, T. L. Rhodes, Z. Y. Li +6
We report the observation of a quasi-coherent density fluctuation (QCF) by the Doppler backscattering system in the scrape-off layer (SOL) region of the DIII-D tokamak. This QCF is…
A Reliable Millimeter-Wave Quadrature Interferometer
M. Gilmore, W. Gekelman, K. Reiling +1
A simple, low-cost millimeter-wave (70 GHz) interferometer with a phase accuracy better than plus or minur 2 degrees, and a response time of 10 ns is described. The simplicity of t…
Overview of recent physics results from MAST
A Kirk, J Adamek, RJ Akers +160
New results from MAST are presented that focus on validating models in order to extrapolate to future devices. Measurements during start-up experiments have shown how the bulk ion…
Dependence of intrinsic rotation reversals on collisionality in MAST
J. C. Hillesheim, F. I. Parra, M. Barnes +6
Tokamak plasmas rotate even without external injection of momentum. A Doppler backscattering system installed at MAST has allowed this intrinsic rotation to be studied in Ohmic L-m…
Measurement of high-k density fluctuation wavenumber spectrum in MAST and Doppler backscattering for spherical tokamaks
J. C. Hillesheim, N. A. Crocker, W. A. Peebles +7
The high-k () wavenumber spectrum of density fluctuations has been measured for the first time in MAST [B. Lloyd et al, Nucl. Fusion 43, 1665 (…
Interaction between Faraday rotation and Cotton-Mouton effects in polarimetry modeling for NSTX
J. Zhang, N. A. Crocker, T. A. Carter +2
The evolution of electromagnetic wave polarization is modeled for propagation in the major radial direction in the National Spherical Torus Experiment (NSTX) with retroreflection f…