A5042580598- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Solar and Space Plasma Dynamics
- Astronomical Observations and Instrumentation
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Spacecraft and Cryogenic Technologies
- Nuclear reactor physics and engineering
- Astronomy and Astrophysical Research
- Particle Accelerators and Free-Electron Lasers
- Nuclear physics research studies
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Plasma Diagnostics and Applications
- Astronomical and nuclear sciences
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Space Exploration and Technology
- Graphite, nuclear technology, radiation studies
- Gamma-ray bursts and supernovae
- History and Developments in Astronomy
- Gas Dynamics and Kinetic Theory
- Advanced Sensor Technologies Research
University of Wisconsin–Madison
2015-2024
Pennsylvania State University
2024
University of Calgary
2024
Energy Center of Wisconsin
2023
Princeton Plasma Physics Laboratory
2017
Columbia University
2017
Auburn University
2017
École Nationale Supérieure des Mines de Paris
2014-2016
TRIUMF
2014-2016
Massachusetts Institute of Technology
2007-2014
The object of this review is to summarize the achievements research on Alcator C-Mod tokamak [Hutchinson et al., Phys. Plasmas 1, 1511 (1994) and Marmar, Fusion Sci. Technol. 51, 261 (2007)] place that in context quest for practical fusion energy. a compact, high-field tokamak, whose unique design operating parameters have produced wealth new important results since it began operation 1993, contributing data extends tests critical physical models into parameter ranges regimes. Using only...
Abstract The EMC3‐Eirene code is improved in many aspects. Ad hoc boundary conditions for intrinsic impurities at the SOL‐core interface are removed by implicitly coupling to a 1D core model. Non‐uniform cross‐field transport coefficients allowed new version. A particle splitting technique implemented improving Monte Carlo statistic low‐temperature ranges of most interest. Domain splitting, which was possible toroidal direction only, now feasible all three directions, facilitating mesh...
Abstract Resilient divertor features connected to open chaotic edge structures in the Helically Symmetric eXperiment are investigated. For first time, an expanded vessel wall was considered that would give space for implementation of a physical target structure. The analysis done four different magnetic configurations with very plasma edges. A resilient interaction pattern identified across all configurations. This manifests as qualitatively similar footprint behavior equilibria. Overall,...
In the Alcator C-Mod tokamak, strong, steady-state variations of molybdenum density within a flux surface are routinely observed in plasmas using hydrogen minority ion cyclotron resonant heating. In/out asymmetries, up to factor 2, occur with either inboard or outboard accumulation depending on major radius resonance layer. These poloidal can be attributed impurity's high charge and large mass neoclassical parallel force balance. The enhances centrifugal force, causing while ion-impurity...
Stellarator configurations with reactor relevant energetic particle losses are constructed by simultaneously optimizing for quasisymmetry and an analytically derived metric ( $\unicode[STIX]{x1D6E4}_{c}$ ), which attempts to align contours of the second adiabatic invariant, $J_{\Vert }$ magnetic surfaces. Results show that this optimization scheme it is possible generate quasihelically symmetric equilibria on scale ARIES-CS completely eliminate all collisionless alpha within normalized...
Transport characteristics and predicted confinement are shown for the Infinity Two fusion pilot plant baseline plasma physics design, a high field stellarator concept developed using modern optimization techniques. predictions made fidelity nonlinear gyrokinetic turbulence simulations along with drift kinetic neoclassical simulations. A pellet fueled scenario is proposed that enables supporting an edge density gradient to substantially reduce ion temperature turbulence. Trapped electron mode...
The magneto-hydrodynamic equilibrium and stability properties of the Infinity Two Fusion Pilot Plant baseline plasma physics design are presented. configuration is a four field period, aspect ratio A = 10 quasi-isodynamic stellarator optimized for excellent confinement at elevated density high magnetic B 9 T. Magnetic surfaces exist in core vacuum retain good surface integrity from to an operational β 1.6%, volume average pressures, corresponding 800 MW Deuterium-Tritium fusion operation....
An analysis of the divertor designs for Infinity Two Fusion Pilot Plant (FPP) Baseline Plasma Design is presented. The uses an m = 5, n 4 magnetic island chain. are A classical that similar to W7-X analyzed using diffusive field line following and fluid code EMC3-Lite . For a baseline 800 MW operating point in Two, conditions where heat flux on plate remains acceptable region analyzed. In addition related, but different novel Large Island Backside Divertor (LIBD) design shown. LIBD promises...
We provide an assessment of the Infinity Two Fusion Pilot Plant (FPP) baseline plasma physics design. is a four-field period, aspect ratio A = 10, quasi-isodynamic stellarator with improved confinement appealing to max-J approach, elevated density and high magnetic fields (⟨ B ⟩ 9 T). At envisioned operating point [800 MW deuterium-tritium (DT) fusion], configuration has robust surfaces based on magnetohydrodynamic (MHD) equilibrium calculations stable both local global MHD instabilities....
In this work, we present a detailed assessment of fusion-born alpha-particle confinement, their wall loads, and stability Alfvén eigenmodes driven by these energetic particles in the Infinity Two Fusion Pilot Plant Baseline Plasma Design, 4-field-period quasiisodynamic stellarator to operate deuterium-tritium fusion conditions. Using Monte-Carlo codes SIMPLE, ASCOT5, KORC-T, study collisionless collisional dynamics guiding-center full-orbit alpha-particles core plasma. We find that energy...
High-pressure noble gas jet injection is a mitigation technique which potentially satisfies the requirements of fast response time and reliability, without degrading subsequent discharges. Previously reported experiments on DIII-D showed good success at reducing deleterious disruption effects. In this paper, results recent Alcator C-Mod are reported. Jointly, these have greatly improved understanding dynamics processes involved in mitigating both machines, sequence events following observed...
Using the Penning trap mass spectrometer TITAN, we performed first direct measurements of $^{20,21}\mathrm{Mg}$, isotopes that are most proton-rich members $A=20$ and $A=21$ isospin multiplets. These were possible through use a unique ion-guide laser ion source, development suppressed isobaric contamination by 6 orders magnitude. Compared to latest atomic evaluation, find $^{21}\mathrm{Mg}$ is in good agreement but $^{20}\mathrm{Mg}$ deviates $3\ensuremath{\sigma}$. reduce uncertainties...
A new optimized quasihelically symmetric configuration is described that has the desir-able properties of improved energetic particle confinement, reduced turbulent transportby 3D shaping, and non-resonant divertor capabilities. The presented in thispaper explicitly for quasihelical symmetry, confinement,neoclassical stability near axis. Post optimization, configurationwas evaluated its performance with regard to transport, idealmagnetohydrodynamic (MHD) at various values plasma pressure,...
Nine stellarator configurations, three quasiaxisymmetric, quasihelically symmetric and non-quasisymmetric are scaled to ARIES-CS size analyzed for energetic particle content. The best performing configurations with regard confinement also perform the on neoclassical {\Gamma}c metric, which attempts align contours of second adiabatic invariant flux surfaces. Quasisymmetric that simultaneously well quasisymmetry have overall confinement, collisional losses under 3%, approaching performance...
Damaging effects of disruptions are a major concern for Alcator C-Mod, ITER and future tokamak reactors. High-pressure noble gas jet injection is mitigation technique which potentially satisfies the operational requirements fast response time reliability, while still being benign to subsequent discharges. Disruption experiments using an optimized system carried out on C-Mod study physics penetration into high pressure plasmas, as well ability impurities convert plasma energy radiation...
This paper assesses the three-dimensional (3D) effects of edge magnetic field structure on divertor/scrape-off layer transport, based an inter-machine comparison experimental data and recent progress 3D transport simulation. The are elucidated as a consequence competition between transports parallel () perpendicular to field, in open lines cut by divertor plates, or islands. has strong impacts functions, such determination density regime, impurity screening detachment control. perturbation...
This paper describes an initial description of the resilient divertor properties quasi-symmetric (QS) stellarators using HSX (Helically Symmetric eXperiment) configuration as a test-case. Divertors in high-performance QS will need to be changes plasma that arise due evolution pressure profiles and bootstrap currents for design. Resiliency is tested by examining strike point patterns from field line following, which configurational changes. A low variation with high corresponds resiliency....
This paper summarizes highlights of research results from the Alcator C-Mod tokamak covering period 2006–2008. Active flow drive, using mode converted ion cyclotron waves, has been observed for first time in a plasma, mix D and 3 He species; toroidal poloidal flows are driven near location conversion layer. ICRF induced edge sheaths implicated both erosion thin boron coatings generation metallic impurities. Lower hybrid range frequencies (LHRF) microwaves have used efficient current profile...
Abstract The ability to exhaust helium as the fusion born plasma impurity is a critical requirement for burning plasmas. We demonstrate in this paper that resonant magnetic perturbation (RMP) fields can be used actively manipulate characteristics. present results from puff/pump studies at TEXTOR example tokamak with pumped limiter and Large Helical Device (LHD) closed helical divertor heliotron/stellarator device. For LHD, effective confinement time <?CDATA $\tau _{p,\text{He}}^{\ast}$ ?>...
Abstract The optimization of helically symmetric experiment (HSX) for reduced microinstability has been achieved by examining a large set configurations within neighborhood the standard operating configuration. This entailed generating database more than 10 6 magnetic-field HSX varying currents in external coils. Using volume-averaged metrics and gyrokinetic simulations, this helped to identify that can be used regulate trapped-electron-mode stability HSX. is also found correlate...
We report on the mass measurements of several neutron-rich $\mathrm{Rb}$ and $\mathrm{Sr}$ isotopes in $A\ensuremath{\approx}100$ region with TITAN Penning-trap spectrometer. By using highly charged ions charge state $q=10+$, masses $^{98,99}\mathrm{Rb}$ $^{98--100}\mathrm{Sr}$ have been determined a precision 6--12 keV, making their uncertainty negligible for $r$-process nucleosynthesis network calculations. The $^{101}\mathrm{Sr}$ has directly first time eight times higher than previous...
Recent research on the Alcator C-Mod tokamak has focused a range of scientific issues with particular emphasis ITER needs and detailed comparisons between experimental measurements predictive models. Research ICRF (ion cyclotron frequencies) heating emphasized origins mitigation metallic impurities while work lower hybrid current drive experiments have linear nonlinear wave interactions that limit efficiency at high densities in regimes low single pass absorption. Experiments core turbulence...
Simulations of the edge a quasi-helically symmetric (QHS) stellarator with geometry based on Helically Symmetric eXperiment (HSX) are performed using coupled codes EMC3–EIRENE. The standard configuration HSX has an island structure outside separatrix, corresponding to 8/7 resonance. In addition configuration, two other configurations examined: one small islands separatrix 16/15 resonance, and large 4/4 Using EMC3–EIRENE, density scans employed, while scaling input power linearly density, in...