334 citations · 388 across the 18 of their papers we have counts for
18 papers
Beam-Tracing-Based Quantitative Reconstruction of Density Fluctuations in QUEST Using Doppler Backscattering
T. Kinoshita, T. Tokuzawa, V. H. Hall-Chen +8
A three-channel X-/Ku-band Doppler backscattering (DBS) system has been developed and installed on QUEST for turbulence and electric-field measurements. In spherical tokamaks, the…
Comparison of DBS measurements of turbulence spectra by vertical-displacement and poloidal-angle scans using the Scotty synthetic diagnostic
Y. T. Tan, V. Hall-Chen, T. Rhodes
Doppler backscattering (DBS) measures electron density fluctuations. The measured wavenumber is typically varied by changing the probe beam poloidal launch angle. As most DBS syste…
Design of a Doppler backscattering diagnostic for the Wisconsin HTS Axisymmetric Mirror (WHAM)
E. Wikarta, U. Kumar, V. H. Hall-Chen +5
The Wisconsin HTS Axisymmetric Mirror (WHAM) is a compact high-field magnetic mirror. In such magnetic mirrors, cross-field transport is dominated by the flute instability (Endrizz…
Design of a multifunctional Doppler backscattering diagnostic for the Pegasus-III Experiment
E. Wikarta, U. Kumar, V. H. Hall-Chen +6
The Doppler backscattering (DBS) diagnostic measures flows and electron density fluctuations. Recent work indicates that DBS can also infer the magnetic pitch angle (Yeoh et al., N…
Forecasting the first Edge Localized Mode (ELM) after LH-transition with a neural network trained on Doppler Backscattering data from DIII-D
Nathan Qi Xuan Teo, Kshitish Barada, Valerian Hall-Chen +2
In H-mode tokamak and stellarator plasmas, edge localized modes (ELMs) lead to the expulsion of heat and particles beyond the edge transport barrier. ELMs cause a loss of energy an…
Beam-tracing and profile evolution for localised beams in inhomogeneous plasmas
Lewin B. S. Marsh, Felix I. Parra, Valerian H. Hall-Chen +1
We derive the beam tracing and profile evolution for the propagation of any localised beam with arbitrary profile through an inhomogeneous cold plasma. We recover standard Gaussian…
Validation of ERMES 20.0 finite element code for MAST Upgrade O-X mode conversion
Ruben Otin, Ying Hao Matthew Liang, Thomas Wilson +2
This study presents the validation of the frequency-domain finite element code ERMES 20.0, benchmarked against Finite Difference Time Domain (FDTD) solvers. The simulations focus o…
Geometrical optics in phase space
I. Y. Dodin, N. A. Lopez, Tingjing Xing +2
Geometrical optics (GO) is widely used for reduced modeling of waves in plasmas but fails near reflection points, where it predicts a spurious singularity of the wave amplitude. We…
A Doppler backscattering diagnostic for the EXL-50U spherical tokamak: plasma considerations and preliminary quasioptical design
Ying Hao Matthew Liang, Valerian Hongjie Hall-Chen, Terry L. Rhodes +2
The EXL-50U spherical tokamak was built by Energy iNNovation to develop technologies for proton-boron fusion in spherical tokamaks (Liu et al., Phys. Plasmas 2024). We present a co…
Conceptual study on using Doppler backscattering to measure magnetic pitch angle in tokamak plasmas
AK Yeoh, VH Hall-Chen, QT Pratt +8
We introduce a new approach to measure the magnetic pitch angle profile in tokamak plasmas with Doppler backscattering (DBS), a technique traditionally used for measuring flows and…
Simulation and analysis of a high-k electron scale turbulence diagnostic for MAST-U
David C. Speirs, Juan Ruiz-Ruiz, Maurizio Giacomin +7
Plasma turbulence on disparate spatial and temporal scales plays a key role in defining the level of confinement achievable in tokamaks, with the development of reduced numerical m…
Using Convolutional Neural Networks to detect Edge Localized Modes in DIII-D from Doppler Backscattering measurements
N. Q. X. Teo, V. H. Hall-Chen, K. Barada +6
In H-mode tokamak plasmas, the plasma is sometimes ejected beyond the edge transport barrier. These events are known as edge localized modes (ELMs). ELMs cause a loss of energy and…
First data and preliminary experimental results from a new Doppler Backscattering system on the MAST-U spherical tokamak
P. Shi, R. Scannell, J. Wen +7
A new Doppler backscattering (DBS) system, consisting of Q-band and V-band, has been installed and achieved its first data on the MAST-U spherical tokamak. The Q-band and V-band ha…
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…
Interpreting Radial Correlation Doppler Reflectometry using Gyrokinetic Simulations
J. Ruiz Ruiz, F. I. Parra, V. H. Hall-Chen +12
A linear response, local model for the DBS amplitude applied to gyrokinetic simulations shows that radial correlation Doppler reflectometry measurements (RCDR, Schirmer et al., Pla…
Beam model of Doppler backscattering
Valerian H Hall-Chen, Felix I Parra, Jon C Hillesheim
We use beam tracing -- implemented with a newly-written code, Scotty -- and the reciprocity theorem to derive a model for the linear backscattered power of the Doppler Backscatteri…
Structural Color 3D Printing By Shrinking Photonic Crystals
Yejing Liu, Hao Wang, Jinfa Ho +9
The rings, spots and stripes found on some butterflies, Pachyrhynchus weevils, and many chameleons are notable examples of natural organisms employing photonic crystals to produce…