Precession drift reversal and rapid transport of trapped energetic particles due to an energetic particle driven instability in the Large Helical Device

Idouakass, Malik; Todo, Y.; Wang, H.; Wang, J.; Seki, R.; Sato, Masahiko

doi:10.1063/5.0059683

Cited by 5 publications

(4 citation statements)

References 32 publications

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“…These Alfvén eigenmode bursts were reproduced successfully using a multiphase simulation based on the MEGA code [38][39][40][41][42][43]. Precession drift reversal and rapid transport of trapped energetic particles were observed in the MEGA simulation of an energetic-particle-driven instability in LHD [44]. The MEGA code can simulate energetic-particle-driven instabilities in stellarators with a helical magnetic axis, such as Heliotron J and CFQS [45][46][47].…”

Section: Kinetic-mhd Hybrid Simulation Resultsmentioning

confidence: 99%

Research Plan of Complex Global Simulation Unit

TODO,

MIURA,

TOIDA

et al. 2023

Plasma and Fusion Research

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Global simulation, which takes into account the interactions between multiple hierarchies, is expected to be realized not only in the field of nuclear fusion research but also in other academic fields. However, such a complex global simulation is difficult to realize because the temporal and spatial scales of the microscopic hierarchy and those of the entire system are generally extremely different. The aim of the Complex Global Simulation Unit at the National Institute for Fusion Science is to develop simulation methods to address the abovementioned issue and to promote simulation research. This unit aims to develop 1) a global simulation of the whole magnetically-confined fusion plasma, including the core and peripheral plasma, based on the kineticmagnetohydrodynamic hybrid simulation coupled with the gyrokinetic Poisson equation, and 2) a methodology with broad applicability for enabling simulations that closely reproduce real-world phenomena, transcending the strong limitations imposed by the capacity and capability of supercomputers. In addition, the unit aims to develop a method for coupling a particle-in-cell simulation and a global analysis of plasma waves. Furthermore, it aims to develop a multiphase (solid, liquid, gas, and plasma) simulation method for pellet injection into fusion plasmas.

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Section: Kinetic-mhd Hybrid Simulation Resultsmentioning

confidence: 99%

Research Plan of Complex Global Simulation Unit

TODO,

MIURA,

TOIDA

et al. 2023

Plasma and Fusion Research

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“…All numerical simulations were performed for the same set of physical parameters, namely for a magnetic shear of s m = 0.80, a maximum shear flow amplitude ϕ max / (ω d0 ∆ψ) of 2.50, an ion temperature of T i = T 0 , an electron temperature of T e = 10T 0 , C e = 0.40 and a polarization term C i = 0.60 in normalized units. Note that in the LHD experiments [1][2][3][4], the electron temperature varies from T i to ∼10T i .…”

Section: Gyrokinetic Numerical Experimentsmentioning

confidence: 99%

“…In the Large Helical Device (LHD), the resistive interchange mode can be destabilized by the neutral beam injection. A new mode is this way generated and referred to as the 'energetic ion driven resistive interchange mode' [1][2][3][4]. This mode is characterized by a global structure on the poloidal and toroidal numbers, m and n, respectively, which here satisfy m/n = 1/1.…”

Section: Introductionmentioning

confidence: 99%

Low-frequency turbulence suppression by amplification of synchronized zonal flow with energetic particle driven modes

Ghizzo,

Del Sarto

2023

Nucl. Fusion

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We investigate the suppression of the turbulent transport associatedto the emergence of spontaneous internal transport barriers, due tothe combined collective effects played by trapped electrons and energeticpassing ions. Numerical experiments performed with a ``particle mode''model based on a double gyro-average over the fast cyclotron phaseand over the bounce (or transit) phases are used to show the roleplayed by energetic particles in the suppression of the ion-temperature-gradientdriven turbulence. We show this occur via phase locking in a Kuramoto-typesynchronization process.

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“…The implementation of this model also includes diamagnetic drifts and plasma rotation that increases the accuracy of the frequency of the simulated instability. This model is implemented on a cylindrical grid, enabling simulations of complex geometries, such as stellerators [39] and tokamaks with externally-applied 3D fields [40]. The kinetic population and the bulk plasma are coupled together by means of including the energetic particle current density term (employing the particle-in-cell method) into the MHD momentum balance equation.…”

Section: Hybrid Kinetic-mhd Modelling: Megamentioning

confidence: 99%

Modelling the Alfvén eigenmode induced fast-ion flow measured by an imaging neutral particle analyzer

Gonzalez-Martin

Du²,

Heidbrink³

et al. 2022

Nucl. Fusion

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An imaging neutral particle analyzer (INPA) provides energy and radially resolved measurements of the confined fast-ion population ranging from the high-field side to the edge on the midplane of the DIII-D tokamak. In recent experiments, it was used to diagnose fast-ion flow in the INPA-interrogated phase-space driven by multiple, marginally unstable Alfvén eigenmodes (AEs). The key features of this measured fast-ion flow are: (I) a fast-ion flow from q min and the injection energy (81 keV) towards lower energies and plasma periphery.(II) A flow from the same location towards higher energies and the plasma core, (III) a phase-space ‘hole’ at the injected energy and plasma core and (IV) a pile-up at the plasma core at lower energies (∼60 keV). Ad hoc energetic particle diffusivity modelling of TRANSP significantly deviates from the observation. Comparably, a reduced modelling, i.e. a combination of NOVA-K and ASCOT5 code with the measured mode structure and amplitude, generally reproduce some key features of the observed phase-space flow, but largely failed to interpret fast ion depletion near the plasma axis. At last, self-consistent, first-principle multi-phase hybrid simulations that include realistic neutral beam injection and collisions are able to reproduce most features of the time-resolved phase-space flow. During consecutive hybrid phases, an RSAE consistent with the experiment grows and saturates, redistributing the injected fast ions. The resulting synthetic INPA images are in good agreement with the measurement near the injection energy. The simulations track the fast-ion redistribution within the INPA range, confirming that the measured fast-ion flow follows streamlines defined by the intersection of phase-space surfaces of constant magnetic moment μ and constant E′ = nE + ωP ϕ , where n and ω are the instability toroidal mode number and frequency, and E and P ϕ the ion energy and toroidal canonical momentum. Nonperturbative effects are required to reproduce the depletion of fast ions near the magnetic axis at the injection energy.

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Precession drift reversal and rapid transport of trapped energetic particles due to an energetic particle driven instability in the Large Helical Device

Cited by 5 publications

References 32 publications

Research Plan of Complex Global Simulation Unit

Research Plan of Complex Global Simulation Unit

Low-frequency turbulence suppression by amplification of synchronized zonal flow with energetic particle driven modes

Modelling the Alfvén eigenmode induced fast-ion flow measured by an imaging neutral particle analyzer

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