Magnetohydrodynamic Vlasov simulation of the toroidal Alfvén eigenmode

Todo, Y.; Sato, Tetsuya; Watanabe, Kunihiko; Watanabe, Tomohiko; Horiuchi, Ritoku

doi:10.1063/1.871235

Cited by 75 publications

(99 citation statements)

References 16 publications

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“…Compared with previous works 4,5 where magnetic moments of alpha particles are set to be zero, the present work has an advantage that a more realistic alpha-particle distribution can be considered. A realistic alpha-particle distribution is really indispensable to the study of alpha-particle losses.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, theoretical and computational studies [3][4][5][6] have shown that wave trapping of resonant particles works as a saturation mechanism of a single TAE mode. It is, however, not clear that the wave-particle trapping works as the dominant saturation mechanism when a large number of TAE modes are destabilized.…”

Section: Introductionmentioning

confidence: 99%

“…We employ a kinetic-MHD hybrid model 12,5 where plasma is divided into two parts, i.e., alpha particles and background plasma. The particle simulation method is used for the alpha-particle component, while the background plasma is described by the full MHD equations which are solved by a finite difference method.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Linear and nonlinear particle-magnetohydrodynamic simulations of the toroidal Alfvén eigenmode

Todo¹,

Sato²

1998

Physics of Plasmas

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160

204

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Linear and nonlinear particle-magnetohydrodynamic ͑MHD͒ simulation codes are developed to study interactions between energetic ions and MHD modes. Energetic alpha particles with the slowing-down distribution are considered and the behavior of nϭ2 toroidal Alfvén eigenmodes ͑TAE modes͒ is investigated with the parameters pertinent to the present large tokamaks. The linear simulation reveals the resonance condition between alpha particles and TAE mode. In the nonlinear simulation, two nϭ2 TAE modes are destabilized and alpha particle losses induced thereby are observed. Counterpassing particles are lost when they cross the passing-trapped boundary. They are the major part of lost particles, but trapped particles are also lost appreciably.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Linear and nonlinear particle-magnetohydrodynamic simulations of the toroidal Alfvén eigenmode

Todo¹,

Sato²

1998

Physics of Plasmas

Self Cite

160

204

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“…Several hybrid simulation models have been constructed [11][12][13][14][15] to study the evolution of AE modes destabilized by energetic particles. In the MEGA code, the bulk plasma is described using nonlinear MHD equations, and the energetic ions are simulated with the δ f particle method.…”

Section: Simulation Modelmentioning

confidence: 99%

Large-Scale Simulation of Energetic Particle Driven Magnetohydrodynamic Instabilities in ITER Plasmas

Todo

Bierwage

2014

Plasma and Fusion Research

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Magnetohydrodynamic (MHD) instabilities driven by energetic alpha particles and beam deuterium particles are investigated for ITER operation scenarios using a hybrid simulation code for energetic particles interacting with an MHD fluid. The particle simulation method with finite Larmor radius effects is applied to both alpha and beam deuterium particles. For the steady-state scenario with 9 MA plasma current, beta-induced Alfvén eigenmodes (BAE modes) with low toroidal mode number (n = 3, 5) were found to become dominant in the nonlinear phase although many toroidal Alfvén eigenmodes (TAE modes) with n ∼ 15 are most unstable in the linear phase. The redistribution of energetic particles with δβ α ∼ δβ beam ∼ 0.07%, which respectively correspond to 6% and 8% of the central values, occurs in the nonlinear phase. When the toroidal mode number of the fluctuations is restricted to n ≤ 8, the redistribution is substantially reduced, thus, suggesting that the resonance overlap between the n ∼ 15 TAE and low-n BAE modes enhances the energetic particle transport in the run with full toroidal mode numbers. For the ITER scenario with 15 MA plasma current, an MHD instability with n = 3 that peaks around the q = 1 (q is the safety factor) magnetic surfaces is driven by bulk plasma current and bulk pressure, and results in significant redistribution of alpha particles with δβ α ∼ 0.3%. For the equilibrium profile with the safety factor profile uniformly raised by 0.1 to remove the q = 1 surfaces, only a benign MHD instability occurs and the energetic particle transport is negligible.

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“…The hybrid simulation model for MHD and energetic particles 23,24,8 is employed in the MEGA code. Plasma is divided into bulk plasma and energetic ions.…”

Section: Simulation Modelmentioning

confidence: 99%

Nonlocal energetic particle mode in a JT-60U plasma

Todo

Shinohara²,

Takechi³

et al. 2004

Physics of Plasmas

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Energetic-ion driven instability in a Japan Atomic Energy Research Institute Tokamak-60 Upgrade (JT-60U) [S. Ishida et al., Phys. Plasmas 11, 2532(2004] plasma was investigated using a simulation code for magnetohydrodynamics and energetic particles. The spatial profile of the unstable mode peaks near the plasma center where the safety factor profile is flat. The unstable mode is not a toroidal Alfvén eigenmode (TAE) because the spatial profile deviates from the expected location of TAE and the spatial profile consists of a single primary harmonic m / n =2/1 where m and n are poloidal and toroidal mode numbers. The real frequency of the unstable mode is close to the experimental starting frequency of the fast frequency sweeping mode. Simulation results demonstrate that energetic-ion orbit width and energetic-ion pressure significantly broaden radial profile of the unstable mode. For the smallest value among the investigated energetic-ion orbit width, the unstable mode is localized within 20% of the minor radius. This gives an upper limit of the spatial profile width of the unstable mode which the magnetohydrodynamic effects alone can induce. For the experimental condition of the JT-60U plasma, energetic ions broaden the radial width of the unstable mode spatial profile by a factor of 3. The unstable mode is primarily induced by the energetic particles.

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Magnetohydrodynamic Vlasov simulation of the toroidal Alfvén eigenmode

Cited by 75 publications

References 16 publications

Linear and nonlinear particle-magnetohydrodynamic simulations of the toroidal Alfvén eigenmode

Linear and nonlinear particle-magnetohydrodynamic simulations of the toroidal Alfvén eigenmode

Large-Scale Simulation of Energetic Particle Driven Magnetohydrodynamic Instabilities in ITER Plasmas

Nonlocal energetic particle mode in a JT-60U plasma

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