A5016542036- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Semiconductor materials and devices
- Plasma Diagnostics and Applications
- Superconducting Materials and Applications
- Plasma and Flow Control in Aerodynamics
- Solar and Space Plasma Dynamics
- Silicon Carbide Semiconductor Technologies
- Laser-Plasma Interactions and Diagnostics
- Scientific Measurement and Uncertainty Evaluation
- Electrostatic Discharge in Electronics
- Particle accelerators and beam dynamics
- Electromagnetic Launch and Propulsion Technology
- Advanced ceramic materials synthesis
- Fusion materials and technologies
- Fluid Dynamics Simulations and Interactions
- Railway Engineering and Dynamics
- Mass Spectrometry Techniques and Applications
- Astro and Planetary Science
- Gas Dynamics and Kinetic Theory
- Atomic and Subatomic Physics Research
- Geophysical Methods and Applications
- Non-Destructive Testing Techniques
- High voltage insulation and dielectric phenomena
- Aerodynamics and Fluid Dynamics Research
The University of Texas at Austin
2020-2024
Fusion Academy
2022
Fusion (United States)
2022
General Atomics (United States)
2020-2022
Columbia University
2022
Ain Shams University
2022
Oak Ridge National Laboratory
2022
Princeton Plasma Physics Laboratory
2022
Princeton University
2022
University of California, Los Angeles
2020-2021
This paper reports on the development of reduced models for electron temperature gradient (ETG) driven transport in pedestal. Model is enabled by a set 61 nonlinear gyrokinetic simulations with input parameters taken from pedestals broad range experimental scenarios. The simulation data has been consolidated new database data, Multiscale Gyrokinetic Database (MGKDB), facilitating analysis. modeling approach may be considered generalization standard quasilinear mixing length procedure....
Abstract Recent evidence points toward the microtearing mode (MTM) as an important fluctuation in H-mode pedestal for anomalous electron heat transport. A study of instabilities region carried out using gyrokinetic simulations to model ELMy DIII-D discharge (USN configuration, 1.4 MA plasma current, and 3 MW heating power) is presented. The produce MTMs, identified by predominantly electromagnetic flux, small particle a substantial degree tearing parity. magnetic spectrogram from Mirnov...
Internal magnetic fluctuation measurements are utilized to identify turbulence associated with micro-tearing modes (MTM) in the DIII-D Edge-Localized-Mode (ELM)-y H-mode pedestal. Using a Faraday-effect polarimeter, (150–500 kHz) is directly observed typical line-averaged amplitude of ∼0.8 G at peak frequency (250 and ∼15 integrated over spectrum from 150 500 kHz. Frequency, poloidal wavenumber, propagation direction all serve as MTM. Magnetic non-monotonically correlates collision...
This article presents a global reduced model for slab-like microtearing modes (MTMs) in the H-mode pedestal, which reproduces distinctive features of experimentally observed magnetic fluctuations, such as chirping and discrete frequency bands at noncontiguous mode numbers. Our model, importantly, includes variation diamagnetic frequencies, is necessary to reproduce experimental observations. The key insight underlying this that MTM instability enabled by alignment rational surface with peak...
Magnetic turbulence is directly observed internally in the pedestal of ELMy H-mode tokamak plasmas using a newly developed Faraday-effect polarimetry measurement. Fluctuation amplitude δbr≥15 G (150–500 kHz), with ratio magnetic to density fluctuation |δbr/B|/|δn/n|≥0.15. identified as resulting from micro-tearing-instability and mode growth accompanied by degraded plasma confinement observed.
The effects that energetic trapped ions have on linear resistive magnetohydrodynamic (MHD) instabilities are studied in a reduced model captures the essential physics driving or damping modes through variations magnetic shear. drift-kinetic orbital interaction of slowing down distribution with MHD instability is integrated to scalar contribution perturbed pressure, and entered into an asymptotic matching formalism for dispersion relation. Toroidal field line curvature included trapping...
In this study, gyrokinetic simulations are used to study pedestal fluctuations for DIII-D discharge 174082 using the GENE code. Nonlinear local indicate that electron heat flux has contributions from temperature gradient-driven transport but at levels insufficient satisfy power balance. We show microtearing modes (MTM) and neoclassical likely account remaining observed energy losses in ion channels, respectively. The MTM instabilities found consistent with high-frequency identified magnetic...
High concentrations of defects at the SiC–SiO2 interface significantly reduce efficiency SiC-based microelectronics. Investigations defect passivation are thus great importance. We report first-principles density-functional-theory calculations for effects fluorine and hydrogen in passivating interface. The show that isolated point involving excessive carbon atoms can be passivated by atomic hydrogen, separately or combined. results further suggest molecular may more effective than fluoride.
Experimental data on electromagnetic fluctuations in DIII-D, made available by the Faraday-effect Radial Interferometer-Polarimeter (RIP) diagnostic, is examined comparison with detailed gyrokinetic simulations using Gyrokinetic Electromagnetic Numerical Experiment (GENE). The diagnostic has unique capability of making internal measurements fluctuating magnetic fields $\frac{\int n_e \delta B_r dR}{\int dR}$. Local linear identify microtearing modes (MTMs) over a substantial range toroidal...
Abstract Wide pedestal quiescent H (WPQH)-mode is an attractive scenario for future burning plasmas as they operate without ELMs. WPQH characterized by formation of a wider and higher (than H-mode), broadband fluctuations in the pedestal. Unlike conventional H-modes, where energy confinement time reduces with increasing heating power, reported this paper do not show power degradation confinement. As injected neutral beam was increased, reduced core ( ρ ⩽ 0.45) transport calculated transp ,...
This article presents a survey of NSTX cases to study the microtearing mode (MTM) stabilities using newly developed global reduced model for Slab-Like Microtearing modes (SLiM). A trained neutral network version SLiM enables rapid assessment (0.05s/mode) MTM with $98\%$ accuracy providing an opportunity systemic equilibrium reconstructions based on matching experimentally observed frequency bands and prediction across wide range parameters. Such method finds some success in discharges,...
We report extensive first‐principles electronic structure modeling and calculations for the SiC–SiO 2 interface, a solid–solid interface formed during oxidation of silicon carbide (SiC). The provides atomic‐scale understanding about nature defects as well passivation effects due to modification bonding. In particular, simulation results show that incorporation hydrogen fluorine decreases defect density, thus enhancing performance SiC‐based devices. Copyright © 2013 John Wiley & Sons, Ltd.