A5051320221- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Plasma Diagnostics and Applications
- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Mass Spectrometry Techniques and Applications
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Ion-surface interactions and analysis
- Silicon and Solar Cell Technologies
- Superconducting Materials and Applications
- Dust and Plasma Wave Phenomena
- Fusion materials and technologies
- Quantum optics and atomic interactions
- Nuclear Physics and Applications
- Electron and X-Ray Spectroscopy Techniques
- Advanced Image Processing Techniques
- Scientific Measurement and Uncertainty Evaluation
- Vacuum and Plasma Arcs
- Advanced Vision and Imaging
- Semiconductor materials and devices
- Astrophysics and Star Formation Studies
- Combustion and flame dynamics
- Image Processing Techniques and Applications
Skolkovo Institute of Science and Technology
2024
Tokamak Energy (United Kingdom)
2021-2024
Tri Alpha Energy (United States)
2013-2019
Weizmann Institute of Science
2004-2018
National Institute of Standards and Technology
2011-2014
Material Measurement Laboratory
2013
University of Missouri
2004
American Committee for the Weizmann Institute of Science
2000
Conventional field-reversed configurations (FRCs), high-beta, prolate compact toroids embedded in poloidal magnetic fields, face notable stability and confinement concerns. These can be ameliorated by various control techniques, such as introducing a significant fast ion population. Indeed, adding neutral beam injection into the FRC over past half-decade has contributed to striking improvements stability. Further, addition of electrically biased plasma guns at ends, end plugs, advanced...
An electron beam ion trap (EBIT) is used to measure extreme ultraviolet spectra between 10 nm and 25 from highly-charged ions of tungsten with an open 3d shell (W XLVIII through W LVI). We found that almost all strong lines are due the forbidden magnetic-dipole (M1) transitions within $3d^n$ ground configurations. A total 37 spectral identified for first time using detailed collisional-radiative (CR) modeling EBIT spectra. new level-merging scheme compactification rate equations described....
TAE Technologies' research is devoted to producing high temperature, stable, long-lived field-reversed configuration (FRC) plasmas by neutral-beam injection (NBI) and edge biasing/control. The newly constructed C-2W experimental device (also called 'Norman') the world's largest compact-toroid (CT) device, which has several key upgrades from preceding C-2U such as higher input power longer pulse duration of NBI system well installation inner divertors with upgraded electrode biasing systems....
Abstract ST40 is a compact, high-field ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>B</mml:mi> <mml:mi mathvariant="normal">T</mml:mi> <mml:mn>0</mml:mn> </mml:mrow> </mml:msub> <mml:mtext>⩽</mml:mtext> <mml:mn>2.1</mml:mn> <mml:mstyle scriptlevel="0"/> <mml:mtext>T</mml:mtext> </mml:math> ) spherical tokamak (ST) with mission to expand the physics and technology basis for ST route commercial fusion. The research programme covers...
Tri Alpha Energy's experimental program has demonstrated reliable field-reversed configuration (FRC) formation and sustainment, driven by fast ions via high-power neutral-beam (NB) injection. The world's largest compact-toroid device, C-2U, was upgraded from C-2 with the following key system upgrades: increased total NB input power ~4 MW (20 keV hydrogen) to 10+ (15 tilted injection angle; enhanced edge-biasing capability inside of each end divertor for boundary/stability control. C-2U...
Neural Architecture Search (NAS) methods are widely used in various industries to obtain high-quality, task-specific solutions with minimal human intervention.Event Sequences (EvS) find widespread use industrial applications, including churn prediction, customer segmentation, fraud detection, and fault diagnosis, among others.Such data consist of categorical real-valued components irregular timestamps.Despite the usefulness NAS methods, previous approaches only have been applied other...
The time history of the local ion kinetic energy in a stagnating plasma was determined from Doppler-dominated line shapes. Using independent determination properties for same region, data allowed inferring time-dependent temperature, and discriminating temperature total energy. It is found that throughout most stagnation period thermal constitutes small fraction energy; latter dominated by hydrodynamic motion. Both energies are observed to decrease electron end period. confirmed available at...
Detailed spectroscopic diagnostics of the stagnating plasma in two disparate z pinches allow, for first time, examination properties within a 1D shock wave picture, demonstrating good agreement with this picture. The conclusion is that wide range imploding-plasma masses and current amplitudes, experiments optimizing non-Planckian hard radiation yields, contrary to previous descriptions pressure balanced by implosion pressure, energy provided kinetic energy, rather than magnetic-field...
The ion kinetic energy in a stagnating plasma was previously determined by Kroupp et al. (Kroupp al., 2011), from Doppler-dominated lineshapes augmented measurements of properties and assuming uniform-plasma model. Notably, the found to be dominantly stored hydrodynamic flow. Here, we advance new description this stagnation as supersonically turbulent. Such turbulence implies non-uniform density distribution. We demonstrate how re-analyze spectroscopic data consistent with turbulent picture,...
The ion-kinetic energy throughout $K$ emission in a stagnating plasma was determined from the Doppler contribution to shapes of optically thin lines. X-ray spectroscopy with remarkably high spectral resolution, together simultaneous imaging along pinch, employed. Over period, drop down electron thermal seen. Axially resolved time-dependent electron-density measurements and absolute intensities line continuum allowed for investigating, first time, each segment balance between at plasma, total...
The NIST electron beam ion trap (EBIT) was used to measure the ${D}_{1}$(3$s$-3${p}_{1/2}$) and ${D}_{2}$(3$s$-3${p}_{3/2}$) transitions in Na-like ions of xenon, barium, samarium, gadolinium, dysprosium, erbium, tungsten, platinum, bismuth. wavelengths are range 3--12 nm. Relativistic many-body perturbation theory calculations were carried out for ${D}_{1}$ ${D}_{2}$ lines every element isoelectronic sequence from argon ($Z$ $=$ 18) uranium 92), taking into account some higher-order terms...
This study investigates self-supervised learning techniques to obtain representations of Event Sequences. It is a key modality in various applications, including but not limited banking, e-commerce, and healthcare. We perform comprehensive generative contrastive approaches learning, applying them both independently. find that there no single supreme method. Consequently, we explore the potential benefits combining these approaches. To achieve this goal, introduce novel method aligns...
Abstract Like most magnetic confined fusion experiments, the ST40 tokamak started off with a small subset of diagnostics and gradually increased diagnostic set to include more complex comprehensive systems. To make each operational phase, forward models various are used developed aid design, provide consistency-checks during commissioning, test analysis methods, build workflows constrain high-level parameters inform interpretation, theory modelling. For new workflows, minimum-viable-products...
Extreme ultraviolet spectra of highly-charged hafnium, tantalum and gold were produced with an electron beam ion trap (EBIT) at the National Institute Standards Technology (NIST) recorded a flat-field grazing-incidence spectrometer in wavelength range 4–20 nm. The energy was varied between 1.84 5.15 keV to selectively enhance from specific ionization stages. Identifications strong n = 4–n 4 transitions Rb-like hafnium (35+) Co-like (52+) determined aid collisional-radiative modelling EBIT...
The difference between the ion thermal and effective temperatures is investigated through simulations of Ne gas puff z-pinch reported by Kroupp et al. [Phys. Rev. Lett. 107, 105001 (2011)]. Calculations are performed using a 2D, radiation-magnetohydrodynamic code with Tabular Collisional-Radiative Equilibrium, namely Mach2-TCRE [Thornhill al., Phys. Plasmas 8, 3480 (2001)]. extensive data set imaging K-shell spectroscopy from experiments provides challenging validation test for simulations....
Extreme ultraviolet spectra of highly charged barium atoms were produced with an electron beam ion trap (EBIT) and recorded a flat-field grazing-incidence spectrometer. The measured in the wavelength range 4 nm–24 nm energies varying from 700 eV to 30 000 eV. line identifications performed collisional-radiative modeling EBIT plasma that provided good quantitative agreement between simulated spectra. In energy eV–1750 eV, fifty three n = 4–n transitions Se-like (Ba22+) Cu-like (Ba27+) ions...
Extreme ultraviolet spectra of highly charged xenon atoms were produced with an electron beam ion trap (EBIT) at the National Institute Standards and Technology recorded a flat-field grazing-incidence spectrometer. The measured in wavelength range 4.5–19.5 nm as energy was varied between 1.5 5.9 keV. Different ionization stages enhanced various energies. Wavelength calibration provided by neon, argon iron, well previously lines xenon. Identifications strong n = 3–n 3 transitions from Ni-like...
Recent investigations of the interaction fast-rising magnetic fields with multi-species plasmas at densities 1013–1015 cm−3 are described. The configurations studied planar or coaxial interelectrode gaps pre-filled plasmas, known as plasma opening switches. diagnostics based on time-dependent, spatially resolved spectroscopic observations. Three-dimensional spatial resolution is obtained by plasma-doping techniques. measurements include propagating field structure, ion velocity...
Two-dimensional 3-ns-gated visible images, recorded at different times during the implosion of plasma under azimuthal magnetic field ( <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$Z$</tex></formula> -pinch), revealed ringlike instabilities followed by development axially and azimuthally nonuniform structures in imploding plasma. Remarkably, evolution time all was found to be highly repeatable...
Field Reversed Configurations (FRCs) heated by neutral beam injection may include a large fast ion pressure that significantly modifies the equilibrium. A new analysis is required to characterize such hybrid FRCs, as simple relations used up now prove inaccurate. The substantial contributions of ions FRC radial balance and diamagnetism are described. model offered reconstruct more accurately equilibrium parameters elongated FRCs. Further modeling requires measurements either magnetic field...
In this paper, a calibration adjustment factor was inadvertently applied twice to the experimental wavelengths for Ta and therefore in table 3 were shifted by few thousandths of nm. The correct values (in nm) are given pdf file.
C-2 is a unique, large compact-toroid (CT) device at Tri Alpha Energy that produces field-reversed configuration (FRC) plasmas by colliding and merging oppositely directed CTs. Significant progress has recently been made on C-2, achieving ~5 ms stable with dramatic improvement in confinement, far beyond the prediction from conventional FRC scaling. This stable, long-lived plasma state called high-performance (HPF) regime. The key approaches to achieve HPF regime are as follows: (i) dynamic...
A dual wavelength imaging system has been developed and installed on C-2U to capture 2D images of a He jet in the Scrape-Off Layer (SOL) an advanced beam-driven Field-Reversed Configuration (FRC) plasma. The was designed optically split two identical pass them through 1 nm FWHM filters. Dual are focused adjacent large format CCD chip recorded simultaneously with time resolution down 10 μs using gated micro-channel plate. relatively compact optical cm plasma region spatial 0.2 can be used...
Abstract We present a new state-of-the-art Triple Wavelength Spectrometer (TriWaSp), recently deployed on ST40, high field low aspect ratio spherical tokamak. The TriWaSp has range of possible applications due to its flexible design; the current configuration focuses charge exchange recombination spectroscopy from carbon and neon impurities in ST40 plasma. This paper discusses detailed setup system presents initial ion temperature measurements using single line sight, which show good...