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Plasma Science and Technology 2009年第6期11卷 647-650页

作者：李德徽匡光力王少杰 institute of Plasma physics Chinese Academy of Sciences Center for Magnetic fusion theory Chinese Academy of Sciences department of Modern physics University of Science and Technology of China

For the effect of the collisional dissipation of fast electrons driven by the lower-hybrid waves, a predictive simulation is made for the HT-7 plasma. The simulation results show that the dissipation of fast electrons counteracts the effect of radial diffusion to some extent, thereby making the lower-hybrid driven current profile closer to the power deposition profile. So, in the case of an off-axis lower-hybrid wave power launching, the dissipation is helpful in maintaining a center-hollowed current profile in lower hybrid current drive （LHCD） plasmas, and thus possibly maintains the desired reversed magnetic shear.

关键词： tokamak reversed magnetic shear lower hybrid current drive collisional dissipation

Radial transport dynamics studies of SMBI with a newly developed TPSMBI code

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Chinese physics B 2016年第10期25卷 279-286页

作者：王亚辉郭文峰王占辉任启龙孙爱萍许敏王爱科项农 institute of Plasma physics Chinese Academy of Sciences University of Science and Technology of China Center for Magnetic fusion theory Chinese Academy of Sciences Southwestern institute of physics

In tokamak plasma fueling, supersonic molecule beam injection(SMBI) with a higher fueling efficiency and a deeper penetration depth than the traditional gas puffing method has been developed and widely applied to many tokamak devices.It is crucial to study the transport dynamics of SMBI to improve its fueling efficiency, especially in the high confinement regime. A new one-dimensional(1D) code of TPSMBI has also been developed recently based on a six-field SMBI model in cylindrical coordinate. It couples plasma density and heat radial transport equations together with neutral density transport equations for both molecules and atoms and momentum radial transport equations for molecules. The dominant particle collisional interactions between plasmas and neutrals, such as molecule dissociation, atom ionization and charge-exchange effects, are included in the model. The code is verified to be correct with analytical solutions and also benchmarked well with the trans-neut module of BOUT++ code. Time-dependent radial transport dynamics and mean profile evolution are studied during SMBI with the TPSMBI code in both slab and cylindrical coordinates. Along the SMBI path, plasma density increases due to particle fuelling, while plasma temperature decreases due to heat cooling. Being different from slab coordinate, the curvature effect leads to larger front densities of molecule and atom during SMBI in cylindrical coordinate simulation.

关键词： transport plasma physics SMBI simulation TPSMBI

Vacuum Poloidal Magnetic Field of Tokamak in Alternating-Current Operation

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Plasma Science and Technology 2010年第6期12卷 657-660页

作者：郭威王少杰李建刚 department of physics Fudan University Center for Magnetic fusion theory Chinese Academy of Sciences department of Modern physics University of Science and Technology of China institute of Plasma physics Chinese Academy of Sciences

Vacuum poloidal magnetic field of tokamak in alternating-current （AC） operation is investigated. It is found that the vacuum magnetic field in AC operation is qualitatively different from that in direct-current （DC） operation. In the DC case, the vacuum magnetic field varies along the poloidal direction with one period, while in the AC case, the vacuum magnetic field varies along the poloidal direction with two periods. This implies that two sets of vertical field coil may be needed for the AC operation.

关键词： vacuum magnetic field AC operation tokamak

Linear hybrid simulations of low-frequency fishbone instability driven by energetic passing particles in tokamak plasmas

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Plasma Science and Technology 2022年第6期24卷 96-104页

作者：杨吉星傅国勇申伟叶民友 School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230026People's Republic of China institute for fusion theory and simulation and department of physics Zhejiang UniversityHangzhou 310027People's Republic of China institute of Plasma physics Chinese Academy of SciencesHefei 230031People's Republic of China

A linear simulation study of energetic passing particle-driven low-frequency fishbone instability in tokamak plasmas has been carried out using the global kinetic-MHD(magnetohydrodynamics)hybrid code M3D-K.This work is focused on the interaction of energetic passing beam ions and n=1 mode with a monotonic safety factor q profile and q_(0)simulation results are similar to the analytic theory of Yu et al.

关键词： fishbone energetic particle hybrid simulations tokamak

Nonlinear Coupling of Reversed Shear Alfvén Eigenmode and Toroidal Alfvén Eigenmode during Current Ramp

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Chinese physics Letters 2021年第3期38卷 50-54页

作者： Shizhao Wei Yahui Wang Peiwan Shi Wei Chen Ningfei Chen Zhiyong Qiu institute for fusion theory and simulation and department of physics Zhejiang UniversityHangzhou 310027China Southwestern institute of physics P.O.Box 432Chengdu 610041China Key Laboratory of Materials Modification by Laser Ionand Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024China

Two novel nonlinear mode coupling processes for reversed shear Alfvén eigenmode(RSAE) nonlinear saturation are proposed and investigated. In the first process, the RSAE nonlinearly couples to a co-propagating toroidal Alfvén eigenmode(TAE) with the same toroidal and poloidal mode numbers, and generates a geodesic acoustic mode. In the second process, the RSAE couples to a counter-propagating TAE and generates an ion acoustic wave quasi-mode. The condition for the two processes to occur is favored during current ramp. Both the processes contribute to effectively saturate the Alfvénic instabilities, as well as nonlinearly transfer of energy from energetic fusion alpha particles to fuel ions in burning plasmas.

关键词： mode nonlinear reversed

Transport Modelling for EAST with LHRF and NBI

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Plasma Science and Technology 2009年第4期11卷 417-421页

作者：周登 Holger St.JOHN 胡业民李国强任启龙欧靖 institute of Plasma physics Chinese Academy of Sciences Centre for Magnetic fusion theory Chinese Academy of Sciences General Atomics

Lower hybrid simulation code （LSC） is integrated into transport code ONETWO to model discharges of EAST with heating and current drive using both lower hybrid wave and neutral beam injection. To test the integration, the current profiles driven by both lower hybrid wave and neutral beam injection are presented for a given equilibrium and sample density and temperature profiles before carrying out a time advancing simulation. For a steady state H-mode discharge, the temperature profiles are evolved using GLF23 transport model with a boundary value specified at the normalized minor radius pN = 0.9. A case of steady state with non-inductively driven current accounting for up to 80% is presented.

关键词： ONETWO LSC EAST modeling

Roles of initial current carrier in the distribution of field-aligned current in 3-D Hall MHD simulations

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Science China(Technological Sciences) 2008年第3期51卷 323-336页

作者： ZHANG XianGuo PU ZuYin MA ZhiWei ZHOU XuZhi institute of Space physics and Applied Technology School of Earth and Space SciencePeking UniversityBeijing 100871China institute of Plasma physics Chinese Academy of SciencesHefei 230031China institute of fusion theory and simulation School of ScienceZhejiang UniversityHangzhou 310027China

A three-dimensional (3-D) Hall MHD simulation is carried out to study the roles of initial current carrier in the topology of magnetic field, the generation and distribu- tion of field aligned currents (FACs), and the appearance of Alfvén waves. Consid- ering the contribution of ions to the initial current, the topology of the obtained magnetic field turns to be more complex. In some cases, it is found that not only the traditional By quadrupole structure but also a reversal By quadrupole structure appears in the simulation box. This can explain the observational features near the diffusion region, which are inconsistent with the Hall MHD theory with the total ini- tial current carried by electrons. Several other interesting features are also emerged. First, motions of electrons and ions are decoupled from each other in the small plasma region (Hall effect region) with a scale less than or comparable with the ion inertial length or ion skin depth di=c/ωp. In the non-Hall effect region, the global magnetic structure is shifted in +y direction under the influence of ions with initial y directional motion. However, in the Hall effect region, magnetic field lines are bent in ?y direction, mainly controlled by the motion of electrons, then By is generated. Second, FACs emerge as a result of the appearance of By. Compared with the prior Hall MHD simulation results, the generated FACs shift in +y direction, and hence the dawn-dusk symmetry is broken. Third, the Walén relation in our simulations is consistent with the Walén relation in Hall plasma, thus the presence of Alfvén wave is confirmed.

关键词： collisionless magnetic reconnection Hall MHD simulation field aligned current (FAC) Alfvén wave Hall effects

Evolution of stress fields during the supercontinent cycle

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Geodesy and Geodynamics 2022年第4期13卷 363-375页

作者： Alexander Bobrov Alexey Baranov Robert Tenzer Schmidt institute of physics of the Earth Russian Academy of SciencesMoscowRussia institute of Earthquake Prediction theory and Mathematical Geophysics Russian Academy of SciencesMoscowRussia department of Land Surveying and Geo-Informatics Hong Kong Polytechnic UniversityHong KongChina

We investigate the evolution of stress fields during the supercontinent cycle using the 2D Cartesian geometry model of thermochemical convection with the non-Newtonian rheology in the presence of floating deformable continents.In the course of the simulation,the supercontinent cycle is implemented several times.The number of continents considered in our model as a function of time oscillates around 3.The lifetime of a supercontinent depends on its dimension.Our results suggest that immediately before a supercontinent breakup,the over-lithostatic horizontal stresses in it(referring to the mean value by the computational area)are tensile and can reach-250 MPa.At the same time,a vast area beneath a supercontinent with an upward flow exhibits clearly the over-lithostatic compressive horizontal stresses of 50-100 МРа.The reason for the difference in stresses in the supercontinent and the underlying mantle is a sharp difference in their viscosity.In large parts of the mantle,the over-lithostatic horizontal stresses are in the range of±25 MPa,while the horizontal stresses along subduction zones and continental margins are significantly larger.During the process of continent-to-continent collisions,the compressive stresses can approximately reach 130 MPa,while within the subcontinental mantle,the tensile over-lithostatic stresses are about-50 MPa.The dynamic topography reflects the main features of the su-percontinent cycle and correlates with real ones.Before the breakup and immediately after the disin-tegration of the supercontinent,continents experience maximum uplift.During the supercontinent cycle,topographic heights of continents typically vary within the interval of about±1.5 km,relatively to a mean value.Topographic maxima of orogenic formations to about 2-4 km are detected along continent-to-continent collisions as well as when adjacent subduction zones interact with continental margins.

关键词： Supercontinent cycle Floating deformable continents Thermochemical convection Horizontal stresses Dynamic topography

Observations of mode frequency increase and the appearance of ITB during the m/n=1/1 kink mode in EAST high electron temperature long pulse operation

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Plasma Science and Technology 2023年第2期25卷 68-76页

作者：晁燕张威胡立群耿康宁徐立清张涛臧庆周天富 institute of Plasma physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031People's Republic of China University of Science and Technology of China Hefei 230026People's Republic of China institute for fusion theory and simulation School of PhysicsZhejiang UniversityHangzhou 310027People's Republicof China

A new long-pulse high electron temperature(Te)regime has been achieved on experimental advanced superconducting tokamak by pure radio frequency heating.In this new scenario,there are mainly two confinement states involving two magneto-hydrodynamic(MHD)modes,one of which is identified as m/n=1/1 kink mode(where m and n are the poloidal and toroidal mode numbers,respectively).The frequency evolution of the kink mode is investigated through the three-dimensional,toroidal,and nonlinear Hall-MHD code CLT.We firstly find that the frequency of the m/n=1/1 kink mode significantly increases during each sawtooth crash and then confirmed it through the experimental data.The simulation results indicate that the increase of the mode frequency is mainly due to the significant increase of the electron diamagnetic frequency nearby the reconnection region.We have also observed the internal transport barrier(ITB)during the m/n=1/1 kink mode.To further investigate this m/n=1/1 kink mode in this new regime,the multi-scale interactions between the m/n=1/1 kink mode and turbulence are discussed.

关键词： sawtooth electron diamagnetic drift ITB multi-scale interaction

Gyrofluid simulation of Ion-Scale Turbulence in Tokamak Plasmas

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Communications in Computational physics 2008年第10期4卷 1245-1257页

作者： Jiquan Li Y.Kishimoto Graduate School of Energy Science Kyoto UniversityUjiKyoto 611-0011Japan institute for fusion theory and simulation ZhejiangUniversityHangzhouChina

An improved three-field gyrofluid model is proposed to numerically simulate ion-scale turbulence in tokamak plasmas,which includes the nonlinear evolution of perturbed electrostatic potential,parallel ion velocity and ion pressure with adiabatic electron response.It is benchmarked through advancing a gyrofluid toroidal global(GFT G)code as well as the local version(GFT L),with the emphasis of the collisionless damping of zonal flows.The nonlinear equations are solved by using Fourier decomposition in poloidal and toroidal directions and semi-implicit finite difference method along radial direction.The numerical implementation is briefly explained,especially on the periodic boundary condition in GFT L version.As a numerical test and also practical application,the nonlinear excitation of geodesic acoustic mode(GAM),as well as its radial structure,is investigated in tokamak plasma turbulence.

关键词： Geodesic acoustic mode(GAM) zonal flow ion temperature gradient(ITG)turbulence gyrofluid simulation tokamak