Effects of resonant magnetic perturbations on neutral beam heating in a tokamak

Hu, Youjun; Xu, Yongjian; Hao, Baolong; Li, Guoqiang; He, Kang; Sun, Yuan; Li, Li; Wang, Jinfang; Huang, J.; Ye, Lei; Xiao, Xiaotao; Wang, Feng; Pan, Changchun

doi:10.1063/5.0069792

Cited by 5 publications

(3 citation statements)

References 41 publications

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“…The initial phase space positions of the test NBI fast ions were computed by the NBI code TGCO (Hu et al. 2021). Birth distributions of NBI ions in the poloidal cross-section and from the top view are shown in figure 4.…”

Section: Simulation Set-upmentioning

confidence: 99%

Guiding-centre orbit-following simulations of charge exchange loss of NBI ions with the finite Larmor radius effect

Xu,

Wang,

et al. 2023

J. Plasma Phys.

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Guiding-centre orbit-following simulations of the charge exchange (CX) loss of neutral beam injection (NBI) ions are presented. The finite Larmor radius (FLR) effect in the fast ion–neutral collision can be included in guiding-centre orbit-following simulations by using the gyroaverage method. It is proved that the neutralization probability of fast ions computed by using the gyroaverage method in the guiding-centre orbit simulation is roughly the same as that computed in the full-orbit simulation when the time step in the guiding-centre simulation is the order of the gyroperiod. The CX losses of NBI fast ions for two NBIs in the EAST tokamak have been simulated by the guiding-centre orbit-following code GYCAVA, and the FLR effect in the fast ion–neutral collision on CX losses has been numerically studied. The CX effect of the fast ion–neutral collision can significantly enhance NBI ion losses on EAST. The FLR effect in the fast ion–neutral collision can enhance the CX loss. Vertical asymmetry of localized heat loads induced by CX losses is found, which is related to the FLR effect of fast ions and the strong radial gradient of the neutral density near the plasma edge. Heat loads induced by CX losses are localized in the regions near the poloidal angle $\theta =-60^\circ$ , because the likelihood of exchanging charge is the largest at gyrophase $\xi ={\rm \pi}$ , and this leads to fast downwards moving neutrals. Fast ion loss fractions induced by CX increase with the neutral density increasing.

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Section: Simulation Set-upmentioning

confidence: 99%

Guiding-centre orbit-following simulations of charge exchange loss of NBI ions with the finite Larmor radius effect

Xu,

Wang,

et al. 2023

J. Plasma Phys.

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“…We have developed a test particle code GYCAVA [22,23] based on the modern gyrokinetic theory [24] for investigating the behavior of fast particle in a tokamak. The GYCAVA code as well as the NBI code TGCO [25] have been used for studying effects of the resonant magnetic perturbations [26] and the toroidal field ripple [27] on NBI ion losses in the EAST tokamak. In our previous work, the GYCAVA code has been used to numerically study alpha particle losses with the toroidal field ripple in the CFETR steady-state [28] and hybrid [29] scenarios for different loss boundaries.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of alpha particle loss with toroidal field ripple based on CFETR steady-state scenario

Li 李,

Xu 徐,

Zhong 钟

et al. 2024

Chinese Phys. B

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Effects of plasma equilibrium parameters on the alpha particle loss with the toroidal field ripple based on the CFETR steady-state scenario have been numerically investigated by the orbit-following code GYCAVA. It is found that alpha particle losses decrease and loss regions become narrower with the plasma current increasing or with the magnetic field decreasing. It is because the ripple stochastic transport and the ripple well loss of alpha particle are reduced with the safety factor decreasing. Decrease of the plasma density and temperature can reduce alpha particle losses due to enhancement of the slowing-down effect. The direction of the toroidal magnetic field can significantly affect heat loads induced by lost alpha particle. The vertical asymmetry of heat loads induced by the clockwise and counter-clockwise toroidal magnetic fields are due to the fact that the ripple distribution is asymmetric about the mid-plane, which can be explained by the typical orbits of alpha particle. The maximal heat load of alpha particle for the clockwise toroidal magnetic field is much smaller than that for the counter-clockwise one.

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“…The orbit code GYCAVA has been used for investigating the neutral beam injection (NBI) ion loss in the presence of the resonant magnetic perturbations [26] or the ripple field [27]. In our previous numerical results of NBI ion loss on EAST computed by the orbit code GYCAVA and the NBI code TGCO [28], the outer boundary effect can impact the loss fraction and the heat load of NBI ions [29]. Therefore, it is necessary to study the boundary effect on the alpha particle loss in the CFETR tokamak.…”

Section: Introductionmentioning

confidence: 99%

Simulations of energetic alpha particle loss in the presence of toroidal field ripple in the CFETR tokamak

Xu¹,

Zhang²,

Chen³

et al. 2022

Plasma Sci. Technol.

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Energetic alpha particle losses with the toroidal field ripple and the Coulomb collision in the CFETR tokamak have been simulated by using the orbit-following code GYCAVA for the steady-state and hybrid scenarios. The effects of the outer boundary and the ripple amplitude on alpha particle losses have been investigated. The loss fractions and heat loads of alpha particles in the hybrid scenario are much smaller than those in the steady-state scenario for a significant ripple amplitude. Some alpha particles in the plasma core are lost due to the ripple stochastic transport for a large ripple amplitude parameter. The heat loads with the LCFS boundary are different from those with the wall boundary for the CFETR tokamak, which can be explained by typical alpha particle orbits. Discrete heat load spots have been observed in alpha particle loss simulations, which is due to the ripple well loss. The transition of the lost alpha particle behavior from the ripple stochastic diffusion to the ripple well trapping has been identified in our CFETR simulations. The Coulomb collision effect is responsible for this transition.

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Effects of resonant magnetic perturbations on neutral beam heating in a tokamak

Cited by 5 publications

References 41 publications

Guiding-centre orbit-following simulations of charge exchange loss of NBI ions with the finite Larmor radius effect

Guiding-centre orbit-following simulations of charge exchange loss of NBI ions with the finite Larmor radius effect

Numerical study of alpha particle loss with toroidal field ripple based on CFETR steady-state scenario

Simulations of energetic alpha particle loss in the presence of toroidal field ripple in the CFETR tokamak

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