A5042695495- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Solar and Space Plasma Dynamics
- Particle accelerators and beam dynamics
- Fusion materials and technologies
- Differential Equations and Boundary Problems
- Real-time simulation and control systems
- Material Science and Thermodynamics
- Nonlinear Waves and Solitons
- Plasma Diagnostics and Applications
- Physics of Superconductivity and Magnetism
- Non-Destructive Testing Techniques
- Geophysical and Geoelectrical Methods
- Laser-Plasma Interactions and Diagnostics
- Advanced Control Systems Design
- Hydraulic and Pneumatic Systems
- Meteorological Phenomena and Simulations
- Advanced Control Systems Optimization
- Magnetic Field Sensors Techniques
University of Science and Technology of China
2016-2024
Chinese Academy of Sciences
2016-2024
University of Saskatchewan
2016-2022
University of California, Los Angeles
2016-2022
Institute of Plasma Physics
2016-2022
Polytechnic University of Turin
2021-2022
Abstract A new type of fast particle instability involving axisymmetric modes in magnetic fusion tokamak plasmas is presented. The relevant dispersion relation involves three roots. One corresponds to a vertical plasma displacement that, the absence active feedback stabilization, grows on wall resistivity time scale. other two, oscillating close poloidal Alfvén frequency, are normally damped by resistivity. resonant interaction with ions can drive oscillatory roots unstable. Resonance...
The Keda Torus eXperiment (KTX) is a new reversed field pinch (RFP) device at the University of Science and Technology China. construction assembly KTX, including vacuum chamber, conducting shell, magnetic windings, power supply system, active control coils, pump data acquisition have been completed on August 1, 2015. Immediately following that, first plasma was obtained 15, Intensive conditioning machine underway to ramp up current toward its full operation. An feedback mode system has...
Abstract An analytic derivation of the relevant dispersion relation for vertical displacements in shaped tokamak plasmas is presented, valid arbitrary values ellipticity parameter. The theory developed within framework reduced ideal-MHD model. A nearby, perfectly conducting wall can provide passive feedback stabilization on timescale. mechanism relies image currents induced metallic wall. However, if plasma extends to magnetic separatrix, where X-points are located, as case a divertor...
Abstract The Keda Torus eXperiment (KTX) is still operated in the commissioning phase, and preparation for operation capability of KTX phase II upgrade underway. diagnostics have been greatly developed: (1) terahertz interferometer has upgraded to seven chords electron density profile inversion; (2) a Thomson scattering system with 5 Joule laser installed progress; (3) 3D movable probe developed electromagnetic turbulence measurement; (4) double-foil soft x-ray imaging set up bench test...
Vertical displacement normal modes in shaped tokamak plasmas are studied analytically, based on the reduced ideal-magnetohydrodynamic model. With help of quadratic forms, and using appropriate eigenfunction for vertical displacements with toroidal mode number $n=0$ dominant elliptical-angle $m=1$ , a dispersion relation is derived, including effects ideal or resistive walls through single parameter, $D_w(\gamma )$ which is, general, function complex eigenfrequency $\gamma = -{\rm i}\omega$ ....
The ideal-MHD theory of axisymmetric modes with toroidal mode number n = 0 in tokamak plasmas is developed. These are resonant at the magnetic X-points divertor separatrix. As a consequence, current sheets form along separatrix, which profoundly affect stability vertical plasma displacements. In particular, separatrix lead to stabilization modes, least on time scale, adding an important ingredient mechanism passive feedback stabilization.
Abstract Since the establishment of eddy current diagnostic system within Keda Torus eXperiment (KTX) device, it has unveiled many applications. Recent developments have introduced innovative data analysis techniques alongside compelling experimental results, underscoring necessity for a comprehensive summary system's approaches and broad Notable features encompass exceptional precision, ability to shell currents on entirety closed boundary, vector detection currents, measurement diverse...
In a reversed field pinch device, the conductive shell is placed as close possible to plasma so balance during discharge. Plasma instabilities such resistive wall mode and certain tearing modes, which restrain high parameter operation, respond closely with conditions in wall, essence eddy current present. Also, effect of currents induced by external coils cannot be ignored when active control applied instabilities. One diagnostic tool, an probe array, detects composite shell. Magnetic probes...
Theoretical and experimental considerations suggest that axisymmetric perturbations are resonant at the X-point(s) of a magnetic divertor separatrix may play role in understanding Edge Localized Modes tokamak experiments their active control via so-called vertical kicks. With this motivation mind, first step development an analytical model for resistive X-point modes is presented, i.e., finding adequate, but same time relatively simple magnetohydrodynamic equilibrium plasma column with...
Abstract The trajectory of the compact torus (CT) within a tokamak discharge is crucial to fueling. In this study, we developed penetration model with vacuum magnetic field region accurately determine CT trajectories in discharges. This was used calculate and parameters injections by applying both perpendicular tangential injection schemes HL-2A ITER tokamaks. For along tokamak’s major radius direction from outboard, CTs same exhibited 0.08 reduction relative depth when injected into 0.13...
Abstract Axisymmetric modes in shaped tokamak plasmas are normally associated with vertical displacement events. However, not enough attention has been given to the fact that these can be resonant two different ways. Firstly, for a plasma bounded by divertor separatrix, generic n=0 ideal-MHD perturbation, ξ, is singular at X-point(s), where B eq · ∇ξ = 0 , equilibrium magnetic field. As consequence, perturbations give rise current sheets localized along separatrix. Secondly,...
Elongated tokamak plasmas are prone to instability, initiated by vertical displacement perturbations, which can be suppressed if a perfectly conductive wall is placed near the plasma boundary, providing passive feedback stabilization. For more realistic case of resistive wall, mode still grow on relatively slow time scale. Active control then required for complete However, growth far from ideal-MHD marginal stability stable side, i.e., provided that sufficiently close plasma. It shown rate...
The measurement of plasma displacement is one the most basic diagnostic tools in study equilibrium and control a toroidal magnetic confinement configuration. During pulse discharge, eddy current induced vacuum vessel shell will produce an additional field at boundary, which have significant impact on using probes. In newly built Keda Torus eXperiment (KTX) reversed pinch device, composite can be obtained high spatial resolution. This device offers new way to determine for KTX through...
The design of the poloidal field (PF) system includes ohmic heating and equilibrium (EQ) system, is basis for a magnetic confinement fusion device. A coupling between plasma currents, especially eddy current in stabilizing shell, yields difficulties. effects shell on also cannot be ignored. new PF thus proposed. By using low-μ material (μ = 0.001, e 1) instead conductive an electromagnetic model established that can provide continuous distribution shell. In this model, 3D time-domain problem...
A feedback control system has been designed for the Keda Torus eXperiment device to achieve following goals: (a) suppression of error field at poloidal gap, (b) three-dimensional plasma stability control, and (c) improvement discharge quality. The consists a boundary electromagnetic probe array, field-programmable gate linear power amplifier, an active coil array. adopts compound method that includes both passive methods. To plasma, array is used generate localized radial magnetic as needed...
The flux of magnetic helicity characterizes how the topology a field changes and its transport play essential roles in plasma equilibrium instabilities reversed-field pinch (RFP) device configuration. Used to suppress magnetohydrodynamic effectively, stabilizing conducting shell located at boundary an RFP is always characterized by eddy-current distribution that evolves rapidly with time. After measuring analyzing eddy currents on this during tokamak discharges Keda Torus eXperiment device,...
KTX, a reversed field pinch (RFP) device, is equipped with robust Magnetohydrodynamic (MHD) magnetic feedback control system, which comprises two distinct loops: an inner loop used for current to generate field, and outer dedicated control; these loops operate in cascading manner. The Proportional-Integral-Derivative (PID) methodology employed. In the pursuit of achieving superior performance, mathematical analysis conducted on both loops. This rigorous examination culminates design Internal...
KTX, a reversed field pinch (RFP) device, is equipped with robust Magnetohydrodynamic (MHD) magnetic feedback control system, which comprises two distinct loops: an inner loop used for current to generate field, and outer dedicated control; these loops operate in cascading manner. The Proportional-Integral-Derivative (PID) methodology employed. In the pursuit of achieving superior performance, mathematical analysis conducted on both loops. This rigorous examination culminates design Internal...
Abstract Vertical Displacement Oscillatory Modes (VDOM), with frequency in the Alfvén range, are natural modes of oscillation magnetically confined laboratory plasmas elongated cross-section. These axisymmetric arise from interaction between plasma current, which is equilibrium currents flowing external coils, and perturbed induced on a nearby conducting wall. The restoring force exerted by these vertical motion column leads to its oscillatory behavior. An analytic model for VDOM was...
We derive the transport equations from Vlasov-Fokker-Planck equation when velocity space is spherically symmetric. The Shkarofsky's form of Fokker-Planck-Rosenbluth collision operator employed in equation. A closed-form relaxation model for homogeneous plasmas could be presented terms Gauss hypergeometric2F1 functions. This has been accomplished based on Maxwellian mixture model. Furthermore, we demonstrate that classic models such as two-temperature thermal equilibrium and thermodynamic are...
Abstract We derive the transport equations from Vlasov-Fokker-Planck equation when velocity space is spherically symmetric. The Shkarofsky’s form of Fokker-Planck-Rosenbluth collision operator employed in Vlasov-FokkerPlanck equation. A closed-form relaxation model for homogeneous plasmas could be presented terms Gauss hypergeometric2F1 functions. This has been accomplished based on Maxwellian mixture model. Furthermore, we demonstrate that classic models such as two-temperature thermal...