A5054595565- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Metal and Thin Film Mechanics
- Nuclear Physics and Applications
- Semiconductor materials and devices
- Magnetic Field Sensors Techniques
- Dust and Plasma Wave Phenomena
- Engineering Applied Research
- Electron and X-Ray Spectroscopy Techniques
- Silicon and Solar Cell Technologies
- Gyrotron and Vacuum Electronics Research
- Electrical and Thermal Properties of Materials
- Laser-induced spectroscopy and plasma
- Microwave Dielectric Ceramics Synthesis
- Metallurgical Processes and Thermodynamics
- Advancements in Semiconductor Devices and Circuit Design
- Radiation Therapy and Dosimetry
- Vehicle Dynamics and Control Systems
- Catalysts for Methane Reforming
- Plasma Applications and Diagnostics
Shenyang Pharmaceutical University
2025
ITER
2015-2023
Plasma Technology (United States)
2011-2015
Hôpital Saint-François d'Assise
2015
Centre hospitalier universitaire de Québec
2015
Fusion Academy
2011-2013
Fusion (United States)
2011-2013
Massachusetts Institute of Technology
2009-2013
Experiments in Alcator C-Mod (Enhanced D-alpha) EDA H-modes with extrinsic impurity seeding (N2, Ne, and Ar) have demonstrated a direct correlation between plasma energy confinement edge power flow, achieving values of H98 ≥ 1 for flows only marginally exceeding the scaled access to H-mode these conditions. For lower Z (N2 Ne), plasmas high are obtained radiative fraction 85% or larger reduction peak heat flux at divertor by more than factor 5 compared similar attached The thus achieved meet...
Direction reversals of intrinsic toroidal rotation have been observed in diverted Alcator $C$-Mod Ohmic $L$-mode plasmas following electron density ramps. For low discharges, the core is directed cocurrent, and reverses to countercurrent an increase above a certain threshold. Such occur together with decrease fluctuations $2\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}1}\ensuremath{\le}{k}_{\ensuremath{\theta}}\ensuremath{\le}11\text{ }{\mathrm{cm}}^{\ensuremath{-}1}$ frequencies 70 kHz....
Direction reversals of intrinsic toroidal rotation have been observed in Alcator C-Mod ohmic L-mode plasmas following modest electron density or magnetic field ramps. The reversal process occurs the plasma interior, inside q = 3/2 surface. For low plasmas, is co-current direction, and can reverse to counter-current direction an increase above a certain threshold. Reversals from co- are correlated with sharp decrease fluctuations k R ⩾ 2 cm −1 frequencies 70 kHz. at which reverses increases...
Parametric dependences of the heat flux footprint on outer divertor target plate are explored in EDA H-mode and ohmic L-mode plasmas over a wide range parameters with attached plasma conditions.Heat profile shapes found to be independent toroidal field strength, power flow along magnetic lines insensitive x-point topology (single-null versus double-null).The magnitudes widths closely follow that "upstream" pressure profile, which correlated thermal energy content current.Heat decay lengths...
Joint experiment/theory/modelling research has led to increased confidence in predictions of the pedestal height ITER. This work was performed as part a US Department Energy Research Target FY11 identify physics processes that control H-mode structure. The study included experiments on C-Mod, DIII-D and NSTX well interpretation experimental data with theory-based modelling codes. provides ability models for peeling–ballooning stability, bootstrap current, width scaling make correct...
Several seemingly unrelated effects in Alcator C-Mod ohmic L-mode plasmas are shown to be closely connected: non-local heat transport, core toroidal rotation reversals, energy confinement saturation and up/down impurity density asymmetries. These phenomena all abruptly transform at a critical value of the collisionality. At low densities linear regime, with collisionality ?*???0.35 (evaluated inside q?=?3/2 surface), transport exhibits behaviour, is directed co-current, edge profiles...
Ohmic energy confinement saturation is found to be closely related core toroidal rotation reversals in Alcator C-Mod tokamak plasmas. Rotation occur at a critical density, depending on the plasma current and magnetic field, which coincides with density separating linear regime from saturated regime. The directed co-current low abruptly changes direction counter-current when saturates as increased. Since there bifurcation of this reversal very sensitive indicator determination change. results...
Abstract With the continuous deepening of network and information technology, social media has penetrated into various fields, development provides an effective way for dissemination Civic Political Education in colleges universities. This paper proposes innovative disseminating context new builds a practical platform. From level communication subject, audience, content, media, effect risk, evaluation index system power ideological political education universities is constructed with 6...
Power requirements for maintaining sufficiently high confinement (i.e. normalized energy time H 98 ⩾ 1) in H-mode and its relation to threshold power scaling, P th , are of critical importance ITER. In order better characterize these requirements, recent experiments on the Alcator C-Mod tokamak have investigated properties, including edge pedestal global confinement, over a range input powers near above . addition, we examined compatibility impurity seeding with performance operation,...
This paper presents investigations on the role of edge ion heat flux for transitions from L-mode to H-mode in Alcator C-Mod. Previous results ASDEX Upgrade tokamak indicated that a critical value per particle is needed transition. Analysis C-Mod data confirms this result. The indeed found increase linearly with density at given magnetic field and plasma current. Furthermore, indicate L-H transition also increases field. Combining yields general expression These are discussed point view...
This paper presents the results from a systematic study of low-to-high confinement transition (L–H transition) in Alcator C-Mod lower single null plasmas, with ion ∇ B drift favourable direction for H-mode access. The is performed over broad range plasma density , toroidal magnetic field (3.5 T < 5.4 T) and current (0.6 MA I p 1.4 MA). In particular, data at low which were not included or carefully examined by earlier studies, are highlighted our analysis. With large set data, scaling...
A numerical modeling of current profile modification by lower hybrid drive (LHCD) using a fullwave/Fokker-Planck simulation code is presented. MHD stable LHCD discharge on Alcator C-Mod was analyzed, and the from full wave simulations found to show better agreement with experiment than ray-tracing code. Comparison shows that, although can reproduce stochastic spectrum broadening, calculation predicts even wider fills all kinematically allowed domain. This first demonstration in multi-pass...
Abstract Transitions from the L-mode regime to I-mode regime, with an energy transport barrier, and H-mode both particle barrier are studied on Alcator C-Mod tokamak. Steady plasmas have been produced over a wide range of plasma field (3–6 T), current (0.8–1.35 MA), density shaping in unfavourable ion B × ∇ configuration. The power threshold for L–I transition is higher than scalings L–H favourable drift, increases as well density. Threshold conditions I–H more variable. In some maintained...
Assessing the performance of lower hybrid current drive (LHCD) at high density is critical for developing non-inductive systems on future steady-state experiments. Excellent LHCD efficiency has been observed during fully operation (η=2.0−2.5×1019 AW–1m–2 n¯e=0.5×1020 m–3) Alcator C-Mod [I. H. Hutchinson et al., Phys. Plasmas 1, 1511 (1994)] under conditions (ne, magnetic field and topology, frequency) relevant to ITER [S. Shiraiwa Nucl. Fusion 51, 103024 (2011)]. To extend these results...
Transport in ohmically heated plasmas Alcator C-Mod was studied both the linear (LOC) and saturated (SOC) ohmic L-mode confinement regimes importance of turbulent transport region r/a = 0.5–0.8 established. After an extensive analysis with TGLF GYRO, it is found that using effective impurity ion species Zi = 8, moderately high Zeff (2.0–5.6), LOC regime electron becomes dominant due to TEM turbulence. The key ingredient present results observation dilution main (deuterium) by moderate charge...
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...
H-mode power thresholds (Pth) are examined in Alcator C-Mod lower single null plasmas with standard vertical-plate and slot-type divertor configuration (BT = 5.4 T, Ip 0.9 MA, q95 ∼ 4.0 〈ne〉 (1.3–1.6) × 1020 m−3). The required to access is found be significantly reduced when the plasma operated a slot divertor. lowest Pth achieved ∼0.7 MW, about 1/3 of normal level 40% multi-machine scaling law prediction. does not explicitly correlate shaping parameters (X-point locations, elongation,...
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...
Peaked density profiles in low-collisionality AUG and JET H-mode plasmas are probably caused by a turbulently driven particle pinch, Alcator C-Mod experiments confirmed that collisionality is critical parameter. Density peaking reactors could produce number of important effects, some beneficial, such as enhanced fusion power transport fuel ions from the edge to core, while others undesirable, lower beta limits, reduced radiation plasma edge, consequently higher divertor heat loads....
This paper presents the results of R&D activities recently performed to achieve preliminary design electromagnetic transducers for in-vessel local magnetic field measurements at low frequency (<;30 kHz) ITER. The study is based on thermoelectrical and bench tests a batch 40 sensor prototypes manufactured with temperature cofired ceramic (LTCC) technology. Also, outcomes first neutron irradiation test LTCC sensors are presented. development an alternative concept ITER, mineral insulated...
Experiments on Alcator C-Mod from 2009–2012 have examined the rampup, flattop and rampdown phases of proposed ITER 15 MA baseline scenario. Rampup studies show ICRF heating can significantly reduce V-s requirement, that an H-mode late in ramp this further. modifications to li L-mode are minimal, although Te profile is peaked relative ohmic plasma centre, reduces sawtooth onset times. Flattop plasmas targeting parameters been sustained for 20τE or 8 − 13τCR, but only reach H98 ∼ 0.6 at n/nGr...
Abstract This paper reports on new experiments at Alcator C-Mod that were performed in order to investigate the long-standing, unresolved discrepancy between Thomson scattering (TS) and electron cyclotron emission (ECE) measurements of temperature high tokamak plasmas. Ion range frequency (ICRF) heating is used produce conditions where type TS-ECE observed past JET TFTR should become observable. At C-Mod, plasmas with T e (0) up 8 keV are obtained using ion resonance (ICRH), ICRF mode...
Diagnostics play a very important role in the modern Tokamak where optimum performance is essential. To achieve this, device must be equipped with reliable and robust sensors instrumentation that allow operation envelope to fully explored. Development of these diagnostics maintain this reliability necessary. Further development, systems integrated way maintains their while simultaneously satisfying key requirements needed for safety tokamak operation. ITER will have 50 diagnostics; almost...