Hybrid magnetohydrodynamic-particle simulation of linear and nonlinear evolution of Alfvén modes in tokamaks

Briguglio, S.; Zonca, F.; Vlad, G.

doi:10.1063/1.872997

Cited by 87 publications

(149 citation statements)

References 46 publications

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“…The code XHMGC, developed at the Frascati laboratories, is the extended version [27] of the HMGC [15,26], a nonlinear code based on the hybrid MHD gyrokinetic model [31].…”

Section: A Xhmgcmentioning

confidence: 99%

“…Both numerical and analytic works [15,16] have shown that these modes saturate because a macroscopic distortion of the whole fast-ion pressure profile, accompanied by a significant variation of mode frequency and spatial structure. It has been shown [16] that this mechanism can give rise to avalanches, with an outwardly moving front of pressure gradient: shear-Alfvén continuum oscillations are driven progressively unstable by the radially drifting free energy source.…”

Section: Introductionmentioning

confidence: 99%

“…To overcome the unsatisfactory character of a numerical analysis (apparently limited to a certain numerical tool and to the specific problem analysed), we compare the results obtained by different codes, each applied to a different problem. In particular, we present the results obtained by two 3D codes: XHMGC [15,26,27] and HAGIS [28]; and a simple δf Vlasov-Poisson 1D code, PIC1D-PETSc [29,30] (indicated, in the following, as PIC1DP).…”

Section: Introductionmentioning

confidence: 99%

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Saturation of Alfvén modes in tokamak plasmas investigated by Hamiltonian mapping techniques

et al. 2017

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Nonlinear dynamics of single toroidal number gap Alfvén modes destabilised by the the resonant interaction with fast ions is investigated, in Tokamak equilibria, by means of Hamiltonian mapping techniques. The results obtained by two different simulation codes, XHMGC and HAGIS, are considered with reference to n = 2 Beta induced Alfvén Eigenmodes and, respectively n = 6 Toroidal Alfvén Eigenmodes; simulations of the bump-on-tail instability performed by a 1-dimensional code, PIC1DP, are also analysed. A general feature emerges from these results: modes saturate as the resonant-particle distribution function is flattened, because of the fluxes associated to the motion of particles captured in the potential well of the wave, over the whole region where mode-particle power transfer can take place in the linear phase. Such region can be limited by the narrowest of the resonance width and the mode width. In the former case, mode amplitude at saturation exhibits a quadratic scaling with the linear growth rate; in the latter case, a linear growth rate.These findings are explained in terms of the approximate analytic solution of a nonlinear pendulum model. They are also used to prove that the radial width of the single poloidal harmonic sets an upper limit to the radial displacement of passing fast ions produced by a single-toroidal-number gap mode in the large n limit, irrespectively of the possible existence of a large global mode structure formed by many harmonics.

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“…The code XHMGC, developed at the Frascati laboratories, is the extended version [27] of the HMGC [15,26], a nonlinear code based on the hybrid MHD gyrokinetic model [31].…”

Section: A Xhmgcmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Saturation of Alfvén modes in tokamak plasmas investigated by Hamiltonian mapping techniques

et al. 2017

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“…The Hybrid MHD-Gyrokinetic Code (HMGC) [27] can calculate the 4D (e.g. (ρ,θ,v perp ,v para )) alpha particle density in the presence of Alfvén modes.…”

Section: Effect Of Mhd On the Heat Loadmentioning

confidence: 99%

Effects of complex symmetry-breakings on alpha particle power loads on first wall structures and equilibrium in ITER

Shinohara¹,

Kurki-Suonio²,

Spong³

et al. 2011

Nucl. Fusion

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Abstract. Within the ITPA Topical Group on Energetic Particles, we have investigated the impact that various mechanisms breaking the tokamak axisymmetry can have on the fusion alpha particle confinement in ITER as well as on the wall power loads due to these alphas. In addition to the well known TF ripple, the 3D effect due to ferromagnetic materials (in ferritic inserts, FI, and test blanket modules, TBM) and ELM mitigation coils are included in these mechanisms. ITER Scenario-4 was chosen since, due to its lower plasma current, it is more vulnerable for various off-normal features. First, the validity of using a 2D equilibrium was investigated: a 3D equilibrium was reconstructed using the VMEC code, and it was verified that no 3D equilibrium reconstruction is needed but it is sufficient to add the vacuum field perturbations onto an axisymmetric equilibrium. Then the alpha particle confinement was studied using three independent codes, ASCOT, DELTA5D, and F3D OFMC, all of which assume MHD quiescent background plasma and no anomalous diffusion. All the codes gave a loss power fraction of about 0.2% . The distribution of the peak power load was found to depend on the first wall shape. We also made the first attempt to accommodate the effect of fast ion related MHD on the wall loads in ITER using the HMGC and ASCOT codes. The power flux to the wall was found to increase due to the redistribution of fast ion by the MHD activity. Furthermore, the effect of the ELM mitigation field on the fast ion confinement was addressed by simulating NBI ions with the F3D OFMC code. The loss power fraction of NBI ions was found to increase from 0.3 % without the ELM mitigation field to 4-5% with the ELM mitigation field.

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“…Strong energetic particle redistributions are predicted to occur above the EPM excitation threshold [46] in 3D Hybrid MHD-Gyrokinetic simulations [47]. Due to the intrinsic EPM resonant character and their locahzation at the radial position where the drive is strongest [48,49,50], EPMs rapidly redistribute energetic particles.…”

Section: A^ = {(0^/(oj){l-(0p/(o)[l+ (L6{ro/r)^^^ + 05^q^'^ mentioning

confidence: 99%

Nonlinear Dynamics and Complex Behaviors in Magnetized Plasmas of Fusion Interest

Zonca¹,

Chen²

2008

AIP Conference Proceedings

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Abstract. Complexity and self-organization in burning plasmas are consequence of the interaction of energetic ions with plasma instabilities and turbulence; of the strong nonlinear coupling that will take place between fusion reactivity profiles, pressure driven currents, MHD stability, transport and plasma boundary interactions, mediated by the energetic particle population; and finally of the long time scale nonlinear (complex) behaviors that may affect the overall fusion performance and eventually pose issues for the stability and control of the fusion burn. These issues are briefly discussed in this work, with a view on their potential applications to other research areas.

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Hybrid magnetohydrodynamic-particle simulation of linear and nonlinear evolution of Alfvén modes in tokamaks

Cited by 87 publications

References 46 publications

Saturation of Alfvén modes in tokamak plasmas investigated by Hamiltonian mapping techniques

Saturation of Alfvén modes in tokamak plasmas investigated by Hamiltonian mapping techniques

Effects of complex symmetry-breakings on alpha particle power loads on first wall structures and equilibrium in ITER

Nonlinear Dynamics and Complex Behaviors in Magnetized Plasmas of Fusion Interest

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