E. D. Fredrickson
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View article: Observation of stationary filaments with resonant magnetic perturbations in NSTX
Observation of stationary filaments with resonant magnetic perturbations in NSTX Open
The application of resonant magnetic perturbations (RMPs) induces striated heat fluxes on the divertor plate in tokamaks. These striated heat fluxes were previously considered strike point splitting by the intersection between the divertor…
View article: Energetic particle physics: Chapter 7 of the special issue: on the path to tokamak burning plasma operation
Energetic particle physics: Chapter 7 of the special issue: on the path to tokamak burning plasma operation Open
We review the physics of energetic particles (EPs) in magnetically confined burning fusion plasmas with focus on advances since the last update of the ITER Physics Basis (Fasoli et al 2007 Nucl. Fusion 47 S264). Topics include basic EP phy…
View article: The Utah NeoSeq Project: a collaborative multidisciplinary program to facilitate genomic diagnostics in the neonatal intensive care unit
The Utah NeoSeq Project: a collaborative multidisciplinary program to facilitate genomic diagnostics in the neonatal intensive care unit Open
Rapid genomic diagnostics in the Neonatal Intensive Care Unit represents a paradigm shift in medicine with increasing evidence of the utility of early diagnosis, impacting management. The goal of the Utah NeoSeq Project was to implement an…
View article: Isotopic mass effects of tritium-fueled high-performance TFTR supershots
Isotopic mass effects of tritium-fueled high-performance TFTR supershots Open
An increase in total stored energy correlated with the addition of tritium fuel was observed in supershots during the TFTR DT campaign. This supershot regime had strikingly high, centrally peaked ion and electron temperatures, and the larg…
View article: Generative haplotype prediction outperforms statistical methods for small variant detection in next-generation sequencing data
Generative haplotype prediction outperforms statistical methods for small variant detection in next-generation sequencing data Open
Motivation Detection of germline variants in next-generation sequencing data is an essential component of modern genomics analysis. Variant detection tools typically rely on statistical algorithms such as de Bruijn graphs or Hidden Markov …
View article: Nonlinear simulations of GAEs in NSTX-U
Nonlinear simulations of GAEs in NSTX-U Open
A set of nonlinear simulations has been performed in order to study the nonlinear evolution of unstable global Alfvén eigenmodes in the National Spherical Torus Experiment-Upgrade (NSTX-U). Results of the single toroidal mode number, n, si…
View article: Measurement of small island characteristics using high resolution ECE and CER at DIII-D
Measurement of small island characteristics using high resolution ECE and CER at DIII-D Open
The measurements using the high resolution electron cyclotron emission radiometry and the charge exchange and recombination spectroscopy are processed using analytic formulas to allow for the detection of islands as small as 1.9 cm. In con…
View article: NSTX-U research advancing the physics of spherical tokamaks
NSTX-U research advancing the physics of spherical tokamaks Open
The objectives of NSTX-U research are to reinforce the advantages of STs while addressing the challenges. To extend confinement physics of low- A , high beta plasmas to lower collisionality levels, understanding of the transport mechanisms…
View article: Generative Haplotype Prediction Outperforms Statistical Methods for Small Variant Detection in NGS Data
Generative Haplotype Prediction Outperforms Statistical Methods for Small Variant Detection in NGS Data Open
Detection of germline variants in next-generation sequencing data is an essential component of modern genomics analysis. Variant detection tools typically rely on statistical algorithms such as de Bruijn graphs or Hidden Markov Models, and…
View article: On the frequency bifurcations of the MHD startup modes in NSTX
On the frequency bifurcations of the MHD startup modes in NSTX Open
The observed bifurcations of the low frequency (<50 kHz) and low toroidal periodicity (n < 5) magnetohydrodynamic (MHD) activity often present in the initial part of the National Spherical Tokamak Experiment (NSTX) discharges can be …
View article: Excitation of toroidally localized harmonics of global Alfvén eigenmodes
Excitation of toroidally localized harmonics of global Alfvén eigenmodes Open
The spherical tokamak NSTX and the upgraded, higher toroidal field, NSTX-U, routinely create plasmas with large un-thermalized populations of super-Alfvénic fast ions. This population of non-thermal energetic ions excites a broad spectrum …
View article: Microtearding mode study in NSTX using machine learning enhanced reduced model
Microtearding mode study in NSTX using machine learning enhanced reduced model Open
This article presents a survey of NSTX cases to study the microtearing mode (MTM) stabilities using the newly developed global reduced model for Slab-Like Microtearing modes (SLiM). A trained neutral network version of SLiM enables rapid a…
View article: Application of simulations and theory of sub-cyclotron frequency modes to DIII-D
Application of simulations and theory of sub-cyclotron frequency modes to DIII-D Open
Theoretical and numerical study of Alfvén eigenmodes (AEs) in the sub-cyclotron frequency range explains the observed frequency scaling with beam parameters in experiments across different devices. Global Alfvén (GAEs) and compressional Al…
View article: Nonlinear growth of magnetic islands by passing fast ions in NSTX
Nonlinear growth of magnetic islands by passing fast ions in NSTX Open
The growth of magnetic islands in NSTX is modeled successfully, with the consideration of passing fast ions. It is shown that a good quantitative agreement between simulation and experimental measurement can be achieved when the uncompensa…
View article: NSTX-U theory, modeling and analysis results
NSTX-U theory, modeling and analysis results Open
The mission of the low aspect ratio spherical tokamak NSTX-U is to advance the physics basis and technical solutions required for optimizing the configuration of next-step steady-state tokamak fusion devices. NSTX-U will ultimately operate…
View article: Comprehensive variant calling from whole‐genome sequencing identifies a complex inversion that disrupts <scp><i>ZFPM2</i></scp> in familial congenital diaphragmatic hernia
Comprehensive variant calling from whole‐genome sequencing identifies a complex inversion that disrupts <span><i>ZFPM2</i></span> in familial congenital diaphragmatic hernia Open
Background Genetic disorders contribute to significant morbidity and mortality in critically ill newborns. Despite advances in genome sequencing technologies, a majority of neonatal cases remain unsolved. Complex structural variants (SVs) …
View article: Nonlinear growth of magnetic islands by passing fast ions in NSTX
Nonlinear growth of magnetic islands by passing fast ions in NSTX Open
The growth of magnetic islands in NSTX is modeled successfully, with the consideration of passing fast ions. It is shown that a good quantitative agreement between simulation and experimental measurement can be achieved when the uncompensa…
View article: Impact of edge harmonic oscillations on the divertor heat flux in NSTX
Impact of edge harmonic oscillations on the divertor heat flux in NSTX Open
Previously, edge-localized mode (ELM)-free and inter-ELM divertor peak heat flux reduction induced by an edge harmonic oscillation (EHO) was observed in NSTX [Gan et al., Nucl. Fusion 57, 126053 (2017)]. This paper introduces new analysis …
View article: Chirping ion cyclotron emission (ICE) on NSTX-U
Chirping ion cyclotron emission (ICE) on NSTX-U Open
In this work, we report on the discovery on NSTX-U of a qualitatively new type of non-thermal emission from plasmas in the ion-cyclotron frequency range (ICE). This new type of ICE is weakly damped, γdamp/ωICE ≈ 0.14%, low order eigenmodes…
View article: Synergy of coupled kink and tearing modes in fast ion transport
Synergy of coupled kink and tearing modes in fast ion transport Open
One aspect of the interaction between fast ions and magnetohydrodynamic (MHD) instabilities is the fast ion transport. Coupled kink and tearing MHD instabilities have also been reported to cause fast ion transport. Recently, the ‘kick’ mod…
View article: Compressional Alfvén eigenmodes excited by runaway electrons
Compressional Alfvén eigenmodes excited by runaway electrons Open
Compressional Alfvén eigenmodes (CAEs) driven by energetic ions have been observed in magnetic fusion experiments. In this paper, we show that the modes can also be driven by runaway electrons formed in post-disruption plasma, which may ex…
View article: Compressional Alfvén eigenmodes excited by runaway electrons
Compressional Alfvén eigenmodes excited by runaway electrons Open
Compressional Alfvén eigenmodes (CAE) driven by energetic ions have been observed in magnetic fusion experiments. In this paper, we show that the modes can also be driven by runaway electrons formed in post-disruption plasma, which may exp…