A5002859140- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Superconducting Materials and Applications
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Quantum and electron transport phenomena
- Solar and Space Plasma Dynamics
- High-pressure geophysics and materials
- Graphene research and applications
- Geophysical and Geoelectrical Methods
- Advanced Data Storage Technologies
- Vacuum and Plasma Arcs
- Nuclear Physics and Applications
- Electrical Fault Detection and Protection
- Time Series Analysis and Forecasting
- Electromagnetic Launch and Propulsion Technology
- Advanced Combustion Engine Technologies
- Geological and Geochemical Analysis
- Anomaly Detection Techniques and Applications
- Molecular Junctions and Nanostructures
- Human Motion and Animation
- Mental Health Research Topics
- Topological Materials and Phenomena
Huazhong University of Science and Technology
2015-2024
Chengdu University
2018
Peking University
2018
Ministry of Education of the People's Republic of China
2018
China University of Geosciences (Beijing)
2018
State Key Laboratory of Advanced Electromagnetic Engineering and Technology
2014-2016
Abstract Recent J-TEXT research has highlighted the significance of role that non-axisymmetric magnetic perturbations, so called three-dimensional (3D) perturbation (MP) fields, play in a fundamentally 2D concept, i.e. tokamaks. This paper presents results achieved over last two years, especially on impacts 3D MP fields magnetohydrodynamic instabilities, plasma disruptions and turbulence transport. On J-TEXT, resonant (RMP) system, capable providing either static or high frequency (up to 8...
Abstract The J-TEXT capability is enhanced compared to two years ago with several upgrades of its diagnostics and the increase electron cyclotron resonance heating (ECRH) power 1 MW. With application wave (ECW), ECW assisted plasma startup achieved; tearing mode suppressed; toroidal injection 300 kW drives around 24 kA current; fast electrons are generated injected runaway current conversion efficiency increases ECRH power. coupling between 2/1 3/1 modes extensively studied. coupled usually...
Abstract A large number of runaway electrons (REs) generated during disruption will cause huge damage on next generation large-scale tokamak. The influence three-dimensional (3D) helical magnetic perturbations the suppression REs has been explored by a set 3D coils in J-TEXT tokamak, which can excite m/n = −2/2 perturbations. Experimental evidence shows that caused opposite coil current direct plasma towards high field side, simultaneously enhancing fluctuations, would enhance radial loss...
Disruptions have the possibility of causing severe wall damage to large tokamaks like ITER. The mitigation disruption is essential safe operation a large-scale tokamak. shattered pellet injection (SPI) technique, which regarded as primary method for ITER, presents several advantages relative massive gas injection, including more rapid particle delivery, higher total assimilation, and centrally peaked deposition. A dedicated argon SPI system that focuses on runaway current dissipation has...
Abstract Using machine learning (ML) techniques to develop disruption predictors is an effective way avoid or mitigate the in a large-scale tokamak. The recent ML-based have made great progress regarding accuracy, but most of them not achieved acceptable cross-machine performance. Before we predictor, it very important investigate method developing cross-tokamak prediction model. To ascertain elements which impact model’s performance and achieve deep understanding multiple models are trained...
The mitigation of disruption damage is essential to the safe operation a large-scale tokamak. In order achieve ITER, shattered pellet injection (SPI) has been considered as primary measure mitigation. A dedicated argon SPI system, focusing on designed for J-TEXT pure can be formed in freezing tube, then separated from tube and accelerated by punch mechanism. injected with speed 150–300 m s−1. performance Ar compared massive gas (MGI). cooling process observed ECE indicates that deeper...
In order to mitigate the negative effects of plasma disruption a massive gas injection (MGI) valve is designed for joint Texas experimental tokamak. The MGI based on eddy-current repulsion mechanism. It has fueling volume 30 ml. piston made by non-ferromagnetic material, so it can be installed close vacuum vessel which strong toroidal magnetic field. A diode use prevent current oscillation in discharge circuit. drive coil outside chamber. opening characteristics and flow have been tested 60...
Disruption mitigation is essential for the next generation of tokamaks. The prediction plasma disruption key to mitigation. A neural network combining eight input signals has been developed predict density limit disruptions on J-TEXT tokamak. An optimized training method proposed which improved performance. obtained tested 64 shots and 205 non-disruption shots. successful alarm rate 82.8% with a false 12.3% can be achieved at 4.8 ms prior current spike disruption. It indicates that more...
The temporal-spatial structures of plasma flows and turbulence around tearing mode islands are presented. experiments were performed using Langmuir probe arrays in the edge plasmas J-TEXT tokamak. correlation analyses clearly show that have similar m/n = 3/1 as magnetic island does (m n poloidal toroidal numbers, respectively). sign potential fluctuations for inverses powers significantly reduce at q 3 surface. Approaching to last closed flux surface islands, radially elongated flow...
This paper presents the upgraded x-ray imaging crystal spectrometer (XICS) system on Joint Texas Experimental Tokamak (J-TEXT) tokamak and latest experimental results obtained in last campaign. With 500 Hz frame rate of new Pilatus detector 5 cm × 10 spherically bent crystal, XICS can provide core electron temperature (Te), ion (Ti), plasma toroidal rotation (VΦ) with a maximum temporal resolution 2 ms for J-TEXT pure ohmic plasmas. These parameters high are very useful research, especially...
Abstract Runaway currents following disruptions have an important effect on the first wall in current tokamaks and will be more severe next generation tokamaks. The behavior of runaway massive gas injection (MGI) induced been investigated J-TEXT tokamak. cold front by jet penetrates helically along field lines, preferentially toward high side stops at a location near q = 2 surface before disruption. When reaches it initiates magnetohydrodynamic activities results It is found that MGI He or...
Abstract The response of plasma toroidal rotation to the external resonant magnetic perturbations (RMP) has been investigated in Joint Texas Experimental Tokamak (J-TEXT) ohmic heating plasmas. For J-TEXT’s plasmas without application RMP, core is counter-current direction while edge near zero or slightly co-current direction. Both static RMP experiments and rotating have applied investigate rotation. decreases lower level with RMP. At same time, can spin more than 20 km s −1 On other hand,...
The generation of runaway electrons during disruptions poses a serious threat for the operation ITER. efficiency injection large amounts impurities by massive gas or shattered pellet to achieve suppression might be compromised due low mixture and high Rosenbluth density suppression. transport is dominated magnetic perturbations. perturbations have advantage expelling seeds before they reach energy. Robust has been reached on J-TEXT with mode locking application m/n = 2/1 resonant thermal...
The avoidance and suppression of runaway electron (RE) generation during disruptions is great importance for the safe operation tokamaks. Massive gas injection used to suppress REs, but poor mixing efficiency extremely high density required RE make full unreliable. magnetic perturbations provide an alternative disruptions. use mode penetration induced by resonant (RMPs) has been investigated on J-TEXT tokamak. For a sufficiently long duration, robust reached m/n = 2/1 RMP with amplitude...
When the energy of confined runaway electrons approaches several tens MeV, can emit synchrotron radiation in range infrared wavelength. An camera working wavelength 3-5 μm has been developed to study Joint Texas Experimental Tokamak (J-TEXT). The is located equatorial plane looking tangentially into direction electron approach. beam inside plasma observed at flattop phase. With a fast acquisition camera, behavior directly during current plateau following massive gas injection triggered disruptions.
Abstract Developing advanced magnetic divertor configurations to address the coupling of heat and particle exhaust with impurity control is one major challenges currently constraining further development fusion research. It has therefore become focus extensive attention in recent years. In J-TEXT, several new configurations, including high-field-side single-null poloidal island divertor, as well their associated fundamental edge plasma physics, have recently been investigated. The purpose...
The injection of a large amount impurities is one the possible ways mitigating disruption in large-scale tokamaks. deposition at center plasma key to radiation energy and suppression runaway. interaction gas jet with rational surfaces has been studied by scanning current. experimental results show that massive argon can cool from edge core region, cooling process accompanied different magnetohydrodynamic (MHD) modes when reaches corresponding surfaces. It observed safety factors electron...
A spatially distributed hard X-ray detection array has been developed to diagnose the loss of runaway electron with toroidal and poloidal resolution. The radiation in energy ranges 0.3–1 MeV resulted from electrons can be measured. consists 12 CdTe detectors which are arranged surrounding tokamak. It is found that most transport plasma boundary tend on limiters. application electrode biasing probe enhancement local loss. Resonant magnetic perturbations enhanced diffusion showed an asymmetric rate.
Abstract The suppression of runaways following disruptions is key for the safe operation ITER. massive gas injection (MGI) has been developed to mitigate heat loads, electromagnetic forces and runaway electrons (REs) during disruptions. However, MGI may not completely prevent generation REs on Resonant magnetic perturbation (RMP) applied suppress several machines. It was found that strong RMP results in enhancement production instead J-TEXT. current about 50% pre-disruption plasma argon...
Abstract In J-TEXT tokamak, fast electron bremsstrahlung diagnostic with 9 chords equipped multi-channel analyzer enables detailed studies of the generation and transport electrons. The spatial profiles energy spectrum electrons have been measured in two ECCD cases either on-axis or off-axis injection, processed by Abel-inversion are consistent calculated power deposition locations. Moreover, it is observed that increases rapidly after turning off ECCD, which may be attributed to...
In the cold pulse experiments in J-TEXT, not only are rapid electron temperature increases core observed, but also steep rises of inner density found. Moreover, toroidal rotation is accelerated during non-local transport process temperature. These new findings J-TEXT reveal that turbulence spreading possible mechanism for dynamics.
Disruptions have the potential to cause severe damage large tokamaks like ITER. The mitigation of disruption is one essential issues for tokamak. Massive gas injection (MGI) a technique in which amounts noble are injected into plasma order safely radiate energy evenly over entire plasma-facing wall. However, radiated during triggered by massive found be toroidally asymmetric. In investigate spatial and temporal structures radiation asymmetry, power diagnostics J-TEXT tokamak been upgraded....