A5024345216- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Dust and Plasma Wave Phenomena
- Laser-induced spectroscopy and plasma
- Solar and Space Plasma Dynamics
- Superconducting Materials and Applications
- Nuclear Materials and Properties
- High-pressure geophysics and materials
- Laser-Matter Interactions and Applications
- Particle accelerators and beam dynamics
- Atomic and Molecular Physics
- Nuclear reactor physics and engineering
- Laser Design and Applications
- Vacuum and Plasma Arcs
- Gas Dynamics and Kinetic Theory
- Fluid Dynamics and Turbulent Flows
- Metal and Thin Film Mechanics
- Plasma Applications and Diagnostics
- Physics of Superconductivity and Magnetism
- Quantum, superfluid, helium dynamics
- Advanced Thermodynamics and Statistical Mechanics
- Advanced Data Storage Technologies
University of California, San Diego
2016-2025
Moscow Power Engineering Institute
2023
Lawrence Livermore National Laboratory
2014-2020
San Diego Association of Governments
2020
Kurchatov Institute
1992-2018
Moscow Engineering Physics Institute
2014-2018
Plasma (Russia)
2018
Oak Ridge National Laboratory
2007-2014
National University
2014
University of California System
2012
Intermittent plasma objects (IPOs) featuring higher pressure than the surrounding plasma, and responsible for ∼50% of E×BT radial transport, are observed in scrape off layer (SOL) edge DIII-D tokamak [J. Watkins et al., Rev. Sci. Instrum. 63, 4728 (1992)]. Conditional averaging reveals that IPOs, produced at a rate ∼3×103 s−1, positively charged also polarized, poloidal electric fields up to 4000 V/m. The IPOs move poloidally speeds 5000 m/s radially with E×BT/B2 velocities ∼2600 near last...
Intermittent plasma objects (IPOs), featuring higher pressure than the surrounding plasma, are responsible for ∼50% of E×BT radial transport in scrape off layer (SOL) Doublet III D (DIII-D) tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] L- and H-mode discharges. Conditional averaging reveals that IPOs positively charged feature internal poloidal electric fields up to 4000 V/m. The move radially with E×BT/B2 velocities ∼2600 m/s near last closed flux surface (LCFS), ∼330 wall. slow down...
Abstract In this paper we review some theoretical aspects of the dynamics mesoscale filaments extending along magnetic field lines in edge plasma, which are often called ‘blobs’. We start with a brief historical survey experimental data and main ideas on SOL plasma transport, finally evolved into modern paradigm convective very-intermittent cross-field transport. show that both extensive analytic treatments numerical simulations demonstrate blobs enhanced pressure can be convected coherently...
Probe measurements in the PISCES linear device indicate presence of plasma radially far from where it is produced. We show that this mainly caused by large-scale structures with high radial velocity. Data Tore Supra tokamak striking similarities shape these intermittent events as well fluctuation density probability distribution and frequency spectrum. The fact intermittent, are so similar devices tokamaks indicates universality convective transport magnetically confined plasmas.
This paper reviews recent results of the study dust in magnetic fusion devices. Assessment role current devices and ITER is presented. Dust diagnostics, main experimental results, different theoretical aspects plasmas, as well comparison estimates numerical simulations with available data are discussed. Some limitations models dust–plasma interactions gaps approaches to considered. Possible directions for further advancements suggested.
A comprehensive investigation has been performed of the static and dynamic behaviour detached recombining plasmas in linear divertor plasma simulator NAGDIS-II. For stationary detachment, transition from electron-ion recombination (EIR) to molecular activated (MAR) observed by injecting hydrogen gas into high density helium plasmas. The particle loss rate due MAR is found be comparable that EIR. Experiments have also injection a heat pulse produced RF heating demonstrate volumetric...
Recent measurements show that nondiffusive, intermittent transport of particles can play a major role in the scrape-off-layer (SOL) fusion experiments. A possible mechanism for fast convective plasma is related to filaments or “blobs” observed SOL with cameras and probes. In this paper, physical arguments suggesting importance blob [S. I. Krasheninnikov, Phys. Lett. 283, 368 (2001)] have been extended by calculations using three-field fluid model, treating blobs as coherent propagating...
Dust production and accumulation present potential safety operational issues for the ITER. diagnostics can be divided into two groups: of dust on surfaces in plasma. Diagnostics from both groups are employed contemporary tokamaks; new suitable ITER also being developed tested. is likely to occur hidden areas, e.g., between tiles under divertor baffles. A novel electrostatic detector monitoring these regions has been tested at PPPL. In DIII-D tokamak include Mie scattering Nd:YAG lasers,...
The transport of dust particles in tokamak fusion devices is studied using computer simulations with the code, DUSTT. Recent developments modelling DUSTT code are reported. improved model dynamics edge plasmas takes into account several additional effects, including thermionic and secondary electron emission which affects charging heating, grain size effect on thermal radiation, presence impurities plasma. It shown that leads to enhanced heating by plasma boosts destruction particles. zone...
Recent research in scrape-off layer (SOL) and divertor physics is reviewed; new existing data from a variety of experiments have been used to make cross-experiment comparisons with implications for further ITER. Studies the region near separatrix addressed relationship profiles turbulence as well scaling parallel power flow. Enhanced low-field side radial transport implicated driving flows inboard side. The medium-n nature edge localized modes (ELMs) has elucidated measurements determined...
Regime with the plasma detached from divertor targets (detached regime) is a natural continuation of high recycling conditions to higher density and stronger impurity radiation loss. Both theoretical considerations experimental data show clearly that increase loss volumetric recombination causes rollover flux target when increases, which manifestation detachment. Plasma-neutral friction (neutral viscosity effects), although important for sustainment density/pressure upstream providing...
The basic physics of the processes playing most important role in divertor plasma detachment is reviewed. models used two-dimensional edge transport codes that are widely to address different issues and simulate experimental data, as well numerical schemes convergence issues, described. leading ultimate detachment, transition stability detached regime, impact magnetic configuration geometry on considered. A consistent, integral physical picture a tokamak developed.
A viscoelastic model of fuzz growth is presented. The describes the main features tungsten observed in experiments. It gives estimates rate and temperature range close to experimental ones.
Dusty plasmas are electrically quasi-neutral media that, along with electrons, ions, neutral gas, radiation, and electric and/or magnetic fields, also contain solid or liquid particles sizes ranging from a few nanometers to micrometers. These can be found in many natural environments as well various laboratory setups industrial applications. As separate branch of plasma physics, the field dusty physics was born beginning 1990s at intersection interests communities investigating astrophysical...
Abstract Since the publication of review Progress in ITER Physics Basis (PIPB) 2007, significant progress has been made understanding processes at plasma-material interface. This review, part ITPA Nuclear Fusion Special Issue On Path to Burning Plasma Operation , presents these developments, focusing on key areas such as physics plasma exhaust, interactions, and properties plasma-facing materials their evolution under exposure. The coordinated efforts Topical Group Scrape-Off Layer Divertor...
Volume recombination within the Alcator C-Mod [I. H. Hutchinson et al., Phys. Plasmas 1, 1511 (1994)] divertor plasma is measured and found to be a significant fraction of total ion sink under detached conditions. The occurs in regions where Te∼1 eV ne∼1021 m−3. Measurements spatial distribution are presented. determinations rates made by measuring D0 Balmer spectrum using collisional radiative model describing level populations, ionization, D0. concept “recombinations per series photon”...
Cross-field fluctuation-driven transport is studied in edge and scrape-off layer (SOL) plasmas the DIII-D tokamak using a fast reciprocating Langmuir probe array allowing local measurements of particle heat fluxes. Two different non-diffusive mechanisms that can contribute strongly to cross-field SOL high-density discharges are identified compared. The first these involves intermittent events observed at plasma separatrix SOL. Intermittence has qualitatively similar character L-mode ELM-free...
Dust particulates in the size range of 10nm–100μm are found all fusion devices. Such dust can be generated during tokamak operation due to strong plasma∕material-surface interactions. Some recent experiments and theoretical estimates indicate that particles provide an important source impurities plasma. Moreover, a serious threat safety next-step In this paper, experimental observations on devices reviewed. A physical model for transport simulation newly developed code DUSTT discussed. The...
Molecular activated recombination (MAR) has been clearly observed for the first time in a divertor plasma simulator. A small amount of hydrogen gas puffing into helium strongly reduced ion particle flux along magnetic field, although conventional radiative and three-body processes were quenched. Careful comparison Balmer spectra with collisional atomic molecular data indicates that population distribution over levels relatively low principal quantum numbers can be well explained by taking...
Far Scrape-Off Layer (SOL) and near-wall plasma parameters in DIII-D depend strongly on the discharge confinement regime. In L-mode discharges cross-field transport increases with average density flattens far SOL profiles, thus increasing contact low field side (LFS) main chamber wall. H-mode between edge localized modes (ELMs) plasma–wall is weaker than L-mode. During ELM fluxes of particles heat to LFS wall increase transiently above values. Depending conditions, ELMs are responsible for...
Analysis of the experimental data from tokamaks and linear divertor simulators leads to conclusion that plasma recombination is a crucial element detachment. Different mechanisms relevant conditions tokamak scrape-off layer (SOL) are considered. The physics Molecular Activated Recombination (MAR) involving vibrationally excited molecular hydrogen discussed. Although conventional Electron–Ion (EIR) alone can strongly alter parameters, MAR impact be substantial for both SOL simulators....
The first experimental evidence showing the connection between blob/hole formation and zonal-flow generation was obtained in edge plasma of JET tokamak. Holes as well blobs are observed to be born shear layer, where zonal-flows off meso-scale coherent structures, leading disconnection positive negative pressure perturbations. newly formed transport azimuthal momentum up gradient flow drive while moving outwards. During this process energy is transferred from structures zonal flows via...