J. E. Rice
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View article: Measurements of Fusion Yield on the Centrifugal Mirror Fusion Experiment
Measurements of Fusion Yield on the Centrifugal Mirror Fusion Experiment Open
The Centrifugal Mirror Fusion Experiment (CMFX) at the University of Maryland, College Park is a rotating mirror device that utilizes a central cathode to generate a radial electric field which induces a strongly sheared azimuthal $E\times…
View article: Thermal energy mitigation and toroidal peaking effects in JET disruptions
Thermal energy mitigation and toroidal peaking effects in JET disruptions Open
Previous investigations on JET suggest half or less of plasma stored thermal energy Wth is radiated (frad,th≲0.5) using either massive gas injection (MGI) or shattered pellet injection (SPI) disruption mitigation. We investigate whether th…
View article: Ion optical design of the magnetic proton recoil neutron spectrometer for the SPARC tokamak
Ion optical design of the magnetic proton recoil neutron spectrometer for the SPARC tokamak Open
A magnetic proton recoil (MPR) neutron spectrometer is being designed for SPARC, a high magnetic field (BT = 12 T), compact (R0 = 1.85 m, a = 0.57 m) tokamak currently under construction in Devens, MA, USA. MPR neutron spectrometers are ve…
View article: Overview of the neutron diagnostic systems for the SPARC tokamak
Overview of the neutron diagnostic systems for the SPARC tokamak Open
Neutron measurement is the primary tool in the SPARC tokamak for fusion power (Pfus) monitoring, research on the physics of burning plasmas, validation of the neutronics simulation workflows, and providing feedback for machine protection. …
View article: Design of a diamond-based in-vessel soft x-ray detector for the SPARC tokamak
Design of a diamond-based in-vessel soft x-ray detector for the SPARC tokamak Open
The in-vessel silicon diode arrays that are used for soft x-ray detection in many tokamaks are sensitive to neutron damage, making them unsuitable for burning plasma devices such as SPARC. In such a device, the silicon diodes would need to…
View article: SPARC x-ray diagnostics: Technical and functional overview
SPARC x-ray diagnostics: Technical and functional overview Open
An overview is given of SPARC’s three main x-ray diagnostics, with a focus on the functions they fulfill with respect to tokamak operation. The first is an in-vessel soft x-ray tomography diagnostic, aimed at providing early campaign infor…
View article: Development of the prototype for the SPARC hard X-ray monitor
Development of the prototype for the SPARC hard X-ray monitor Open
The SPARC tokamak will be equipped with a hard X-ray (HXR) monitor system capable of measuring the bremsstrahlung emission from runaway electrons with photon energies in excess of about 100 keV. This diagnostic will detect the formation of…
View article: Performance predictions of the SPARC x-ray crystal spectrometers for ion temperature and toroidal rotation measurements
Performance predictions of the SPARC x-ray crystal spectrometers for ion temperature and toroidal rotation measurements Open
SPARC will be outfitted with three systems of x-ray crystal spectrometer arrays. Two of these are designed using cylindrically bent crystals to achieve high spectral-resolution for ion temperature and toroidal velocity measurements via ima…
Further rotation reversal studies in C-Mod L-mode plasmas Open
Studies of core toroidal rotation reversal phenomenology in C-Mod deuterium L-mode plasmas have been expanded to include details of the dependences on plasma current and toroidal magnetic field. Rotation reversal occurs at a critical densi…
Comparison of core Ar<sup>17+</sup> and Mo<sup>32+</sup> toroidal rotation in C-Mod plasmas Open
Core ( r / a 0.5) toroidal rotation from argon (Ar 17+ , 40 AMU) and molybdenum (Mo 32+ , 96 AMU) ions has been compared in C-Mod tokamak plasmas over a wide range of operating conditions and confinement schemes, including Ohmic L-mode in …
Argon pumpout by ICRF waves in C-Mod L- and I-mode plasmas Open
Pumpout of argon ions by ICRF waves has been observed in C-Mod deuterium L- and I-mode plasmas that had a substantial hydrogen fraction. The effect is manifested by a reduction of core argon x-ray brightness up to a factor of 90% on time s…
View article: Overview of the SPARC physics basis towards the exploration of burning-plasma regimes in high-field, compact tokamaks
Overview of the SPARC physics basis towards the exploration of burning-plasma regimes in high-field, compact tokamaks Open
The SPARC tokamak project, currently in engineering design, aims to achieve breakeven and burning plasma conditions in a compact device, thanks to new developments in high-temperature superconductor technology. With a magnetic field of 12.…
View article: Experimental inference of neutral and impurity transport in Alcator C-Mod using high-resolution x-ray and ultra-violet spectra
Experimental inference of neutral and impurity transport in Alcator C-Mod using high-resolution x-ray and ultra-violet spectra Open
We present experimental inferences of cross-field impurity transport coefficients for AlcatorC-Mod plasmas without edge-localized modes, leveraging a novel forward model for the entire Ca K α spectrum, including satellite lines within the …
The very high <i>n</i> Rydberg series of Ar <sup>16+</sup> in Alcator C-Mod tokamak plasmas Open
X-ray transitions of the very high- n Rydberg series in Ar 16+ have been observed from Alcator C-Mod tokamak plasmas. Individual emission lines up to 1s16p-1s 2 have been resolved and the central chord line brightnesses with principal quan…
View article: Experimental Inference of Neutral and Impurity Transport in Alcator\n C-Mod Using High-Resolution X-Ray and Ultra-Violet Spectra
Experimental Inference of Neutral and Impurity Transport in Alcator\n C-Mod Using High-Resolution X-Ray and Ultra-Violet Spectra Open
We present experimental inferences of cross-field impurity transport\ncoefficients for Alcator C-Mod plasmas using a novel forward model for the\nentire Ca K-alpha spectrum, including satellite lines within the spectral\nrange, to compare …
View article: Gyrokinetic simulation of turbulence and transport in the SPARC tokamak
Gyrokinetic simulation of turbulence and transport in the SPARC tokamak Open
The turbulence and transport expected in the SPARC tokamak Primary Reference Discharge (PRD) [P. Rodriguez-Fernandez et al., J. Plasma Phys. 86, 865860503 (2020)] have been investigated with the gyrokinetic code CGYRO [J. Candy et al., J. …
View article: Particle transport constraints via Bayesian spectral fitting of multiple atomic lines
Particle transport constraints via Bayesian spectral fitting of multiple atomic lines Open
Optimized operation of fusion devices demands detailed understanding of plasma transport, a problem that must be addressed with advances in both measurement and data analysis techniques. In this work, we adopt Bayesian inference methods to…
View article: Contamination of argon x-ray spectra by tungsten and other elements commonly found in tokamaks
Contamination of argon x-ray spectra by tungsten and other elements commonly found in tokamaks Open
Emission lines which appear in the spectral ranges of ground state transitions from n = 2 levels in He- and H-like argon ions are discussed. X-ray transitions from elements commonly found in tokamaks (tungsten, molybdenum, iron and sulphur…
Validation of FASTFISH-ID: A new commercial platform for rapid fish species authentication via universal closed-tube barcoding Open
Seafood represents up to 20% of animal protein consumption in global food consumption and is a critical dietary and income resource for the world's population. Currently, over 30% of marine fish stocks are harvested at unsustainable levels…
Dimensionless parameter scaling of intrinsic torque in C-Mod enhanced confinement plasmas Open
A dimensionless parameter dependence study of intrinsic torque has been performed on a database of H- and I-mode plasmas from the Alcator C-Mod tokamak. The torque was determined by comparing intrinsic angular momentum density profiles jus…
Evidence and modeling of turbulence bifurcation in L-mode confinement transitions on Alcator C-Mod Open
Analysis and modeling of rotation reversal hysteresis experiments show that a single turbulent bifurcation is responsible for the Linear to Saturated Ohmic Confinement (LOC/SOC) transition and concomitant intrinsic rotation reversal on Alc…
View article: Predict-first experiments and modeling of perturbative cold pulses in the DIII-D tokamak
Predict-first experiments and modeling of perturbative cold pulses in the DIII-D tokamak Open
Cold pulses are introduced in Ohmic DIII-D tokamak plasmas via injection of impurities with a laser blow-off system, revealing for the first time in this machine a quick increase in core electron temperature shortly after the edge cold-pul…
View article: Perturbative transport modeling of cold-pulse dynamics in Alcator C-Mod Ohmic plasmas
Perturbative transport modeling of cold-pulse dynamics in Alcator C-Mod Ohmic plasmas Open
Perturbative transport experiments in magnetically confined plasmas have shown, for more than 20 years, that the injection of cold pulses at the plasma edge can trigger the increase of core temperature. Predictive heat transport simulation…
In-situ wavelength calibration system for the X-ray Imaging Crystal Spectrometer (XICS) on W7-X Open
An in situ wavelength calibration system for the X-ray Imaging Crystal Spectrometer (XICS) on W7-X has been developed to provide routine calibration between plasma shots. XICS is able to determine plasma flow profiles by measuring the Dopp…
EUV Spectra and Line Ratios of Multiply Ionized Calcium and Argon Atoms in a Laboratory Plasma Open
The utility of Ca in the EUV spectral range of astrophysical observations is limited by a fragmentary and incomplete record of laboratory data. In order to obtain a more comprehensive survey of the Ca line emission in the EUV, we have used…
<i>In situ</i> wavelength calibration system for the X-ray Imaging Crystal Spectrometer (XICS) on W7-X Open
An in situ wavelength calibration system for the X-ray Imaging Crystal Spectrometer (XICS) on W7-X has been developed to provide routine calibration between plasma shots. XICS is able to determine plasma flow profiles by measuring the Dopp…
Diagnostic Accuracy and Utility of FluoroType MTBDR, a New Molecular Assay for Multidrug-Resistant Tuberculosis Open
Most cases of multidrug-resistant (MDR) tuberculosis (TB) are never diagnosed (328,300 of the ∼490,000 cases in 2016 were missed). The Xpert MTB/RIF assay detects resistance only to rifampin, despite ∼20% of rifampin-resistant cases being …