Hybrid-kinetic simulation of resonant interaction between energetic-ions and tearing modes in a tokamak plasma

Zhu, Xiaolong; Chen, Wei; Feng, Wei; Wang, Jialei

doi:10.1088/1741-4326/ab742f

Cited by 22 publications

(20 citation statements)

References 47 publications

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“…In this code, the bulk plasma is described by the resistive MHD equations while the energetic ions are described by the drift-kinetic equations, and the energetic ions' stress tensor P h is added into the momentum equation to include the kinetic effects of EPs [35,39]. The M3D-K code has been extensively applied to investigate MHD modes and EP physics [1,7,24,[40][41][42][43][44][45][46]. The equilibrium parameters of our simulations are based on the HL-2A discharge of BAE in reference [37].…”

Section: M3d-k Model and Parameters' Setupmentioning

confidence: 99%

Hybrid simulations of beta-induced Alfvén eigenmode with reversed safety factor profile

Duan¹,

Fu²,

Cai³

2022

Nucl. Fusion

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Based on the experimental parameters in HL-2A tokamak, hybrid simulations have been carried out to investigate the linear stability and nonlinear dynamics of BAE. It is found that the (m/n=3/2) beta-incuced Alfvén eigenmode (BAE) is excited by co-passing energetic ions with qmin=1.5 in linear simulation, and the mode frequency is consistent with experimental meuasurement. The simulation results show that the energetic ions βh, the injection velocity v0 and orbit width parameter ρh of energetic ions are important parameters determining the drive of BAE. Furthermore, the effect of qmin (with fixed shape of q profile) is studied, and it is found that: when qmin ≤ 1.50, the excited modes are BAEs, which are located near q=1.50 rational surfaces; when qmin > 1.50, the excited modes are simillar to the reversed-shear Alfvén eigenmodes (RSAEs), which are mainly localized around q=qmin surfaces. Nonlinear simulation results show that the nonlinear dynamics of BAE is sensitive to the EP drive. For strongly driven case, firstly, redistribution and transport of engetic ions are trigged by (m/n=3/2) BAE, which raised the radial gradient of energetic ions distribution function near q=2 rational surface, and then an EPM (m/n=4/2) is driven in nonlinear phase. Finally, these two instabilities triggered significant redistribution of energetic ions, which results in the twice-repeated and mostly-downward frequency chirping of (m/n=3/2) BAE. For weakly driven case, there are no (m/n=4/2) EPM being driven and twice-repeated chirping in nonlinear phase, since the radial gradient near q=2 rational surface is small and almost unchanged.

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Section: M3d-k Model and Parameters' Setupmentioning

confidence: 99%

Hybrid simulations of beta-induced Alfvén eigenmode with reversed safety factor profile

Duan¹,

Fu²,

Cai³

2022

Nucl. Fusion

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“…The equations in M3D-K code are solved for velocity stream function U, which is related to the incompressible part of the plasma velocity. The M3D-K code has been successfully and widely utilized to investigate TAE [25,29,30], sawteeth induced energetic-ion loss and redistribution [31], fishbone mode instability [32][33][34][35], beta-induced Alfvén eigenmode [36], the resonant interaction between tearing modes and energetic-ions [37,38] and reversed shear Alfvén eigenmodes [39]. In the present work, we mainly focus on the nonlinear simulation of TAE avalanche on NSTX, including n = 1-4 modes.…”

Section: Introductionmentioning

confidence: 99%

Avalanche transport of energetic-ions in magnetic confinement plasmas: nonlinear multiple wave-number simulation

et al. 2021

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Large burst activity, identified as toroidal Alfv\'{e}n eigenmode (TAE) avalanche, occurs frequently in neutral-beam heated plasmas in National Spherical Torus Experiment (NSTX). Based on the typical experimental observation of TAE avalanche on NSTX, a self-consistent nonlinear multiple wave-number ($k_{\parallel}\simeq n/R$, where $n$ toroidal mode-number and $R$ major radius) simulation associated with TAE avalanches is performed using the experimental parameters and profiles before the occurrence of TAE avalanche as the M3D-K input. The wave-wave nonlinear coupling among different modes and the resonant interaction between different modes and energetic-ions during TAE avalanches are identified in the nonlinear multiple wave-number simulations. The resonance overlap during the TAE avalanche is clearly observed in the simulation. It is found that the effective wave-wave coupling and a sufficiently strong drive are two important ingredients for the onset of TAE avalanches. TAE avalanche is considered to be a strongly nonlinear process and it is always accompanied by the simultaneous rapid frequency-chirping and large amplitude bursting of multiple modes and significant energetic-ion losses. The experimental phenomenon is observed on NSTX and is qualitatively reproduced by the simulation results in this work. These findings indicate that the onset of avalanche is triggered by nonlinearity of the system, and are also conducive to understanding the underlying mechanism of avalanche transport of energetic particles in the future burning plasmas, such as ITER.

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“…The fishbone modes are usually generated from interaction between energetic particles and 𝑚/𝑛 = 1/1 internal kink modes. Recently, the 𝑚/𝑛 = 2/1 fishbonelike modes with amplitude-bursting/frequencychirping phenomenons are firstly observed on HL-2A tokamak, [58,59] as given in Fig. 9.…”

Section: Reviewmentioning

confidence: 98%

Energetic Particle Physics on the HL-2A Tokamak: A Review

Shi¹,

Chen²,

Duan³

2021

Chinese Phys. Lett.

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Interaction between shear Alfvén wave (SAW) and energetic particles (EPs) is one of major concerns in magnetically confined plasmas since it may lead to excitation of toroidal symmetry breaking collective instabilities, thus enhances loss of EPs and degrades plasma confinement. In the last few years, Alfvénic zoology has been constructed on HL-2A tokamak and series of EPs driven instabilities, such as toroidal Alfvén eigenmodes (TAEs), revered shear Alfvén eigenmodes (RSAEs), beta induced Alfvén eigenmodes (BAEs), Alfvénic ion temperature gradient (AITG) modes and fishbone modes, have been observed and investigated. Those Alfvénic fluctuations show frequency chirping behaviors through nonlinear wave-particle route, and contribute to generation of axisymmetric modes by nonlinear wave-wave resonance in the presence of strong tearing modes. It is proved that the plasma confinement is affected by Alfvénic activities from multiple aspects. The RSAEs resonate with thermal ions, and this results in an energy diffusive transport process while the nonlinear mode coupling between core-localized TAEs and tearing modes trigger avalanche electron heat transport events. Effective measures have been taken to control SAW fluctuations and the fishbone activities are suppressed by electron cyclotron resonance heating. Those experimental results will not only contribute to better understandings of energetic particles physics, but also provide technology bases for active control of Alfvénic modes on International Thermonuclear Experimental Reactor (ITER) and Chinese Fusion Engineering Testing Reactor (CFETR).

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Hybrid-kinetic simulation of resonant interaction between energetic-ions and tearing modes in a tokamak plasma

Cited by 22 publications

References 47 publications

Hybrid simulations of beta-induced Alfvén eigenmode with reversed safety factor profile

Hybrid simulations of beta-induced Alfvén eigenmode with reversed safety factor profile

Avalanche transport of energetic-ions in magnetic confinement plasmas: nonlinear multiple wave-number simulation

Energetic Particle Physics on the HL-2A Tokamak: A Review

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