Comparative collisionless alpha particle confinement in stellarator reactors with the XGC gyrokinetic code

Cole, M.; Hager, Robert; Moritaka, Toseo; Lazerson, S.; Kleiber, R.; Ku, S.; Chang, C. S.

doi:10.1063/1.5085349

Cited by 13 publications

(25 citation statements)

References 37 publications

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“…The code EUTERPE has been benchmarked in linear settings against several codes, such as TORB (Sánchez et al 2010), GENE (Helander et al 2015;Görler et al 2016), GYSELA, GKW and ORB5 (Görler et al 2016) and XGC (Cole et al 2019). In a turbulence nonlinear setting it has only been compared with TORB for electrostatic simulations in a screw pinch geometry, so far (Sánchez et al 2010).…”

Section: Benchmark Euterpe-orb5mentioning

confidence: 99%

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Nonlinear gyrokinetic PIC simulations in stellarators with the code EUTERPE

Sánchez

Mishchenko²,

García-Regaña

et al. 2020

J. Plasma Phys.

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In this work, the first nonlinear particle-in-cell simulations carried out in a stellarator with the global gyrokinetic code EUTERPE using adiabatic electrons and realistic plasma parameters are reported. Several studies are conducted with the aim of enabling reliable nonlinear simulations in stellarators with this code. First, EUTERPE is benchmarked against ORB5 in both linear and nonlinear settings in a tokamak configuration. Next, the use of noise control and stabilization tools, a Krook-type collision operator, markers’ weight smoothing and heating sources is investigated. It is studied in detail how these tools influence the linear growth rate of instabilities in both tokamak and stellarator geometries, and their influence on the linear zonal flow evolution in a stellarator. Then, it is studied how these tools allow improvement of the quality of the results in a set of nonlinear simulations of electrostatic turbulence in a stellarator configuration. Finally, these tools are applied to a W7-X magnetic configuration using experimental plasma parameters.

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Section: Benchmark Euterpe-orb5mentioning

confidence: 99%

“…2016) and XGC (Cole et al. 2019). In a turbulence nonlinear setting it has only been compared with TORB for electrostatic simulations in a screw pinch geometry, so far (Sánchez et al.…”

Section: Benchmark Euterpe–orb5mentioning

confidence: 99%

Nonlinear gyrokinetic PIC simulations in stellarators with the code EUTERPE

Sánchez

Mishchenko²,

García-Regaña

et al. 2020

J. Plasma Phys.

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“…It is shown that the high order Fourier harmonics strongly affect their motion, precluding any analytical treatment. Recent studies evaluate the level of trapped αparticle loss in reactor-scale devices as unacceptable [89,90], thus the study of their transport is paramount.…”

Section: α-Particles Diffusionmentioning

confidence: 99%

“…One of the strategies to reduce this transport is to optimize the magnetic field by imposing an approximate field symmetry [12,13,14,15]. While the mitigation of α-particles losses caused by field corrugations for future fusion reactors was widely addressed in the literature [81,91,92,93,90], an understanding of the underlying dynamics and methods for transport evaluation are still scarce or controversial.…”

Section: Objectives and Outlinementioning

confidence: 99%

Statistical description of collisionless α-particle transport in cases of broken symmetry: from ITER to quasi-toroidally symmetric stellarators

Gogoleva¹,

Tribaldos²,

Reynolds-Barredo³

et al. 2020

Nucl. Fusion

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Nuclear fusion has the potential to provide humanity with a safe, clean, abundant, efficient and reliable energy source for the generations to come, but up to date finding a viable fusion reactor concept remains an ongoing area of research. One of the main difficulties to attain economically viable magnetically controlled thermonuclear fusion reactors is the confinement of α-particles. These α-particles are responsible of sustaining the extreme temperatures required for nuclear reactions, and their loss poses a serious threat to the reactor operational control and to its plasma-facing components.viii RESUMEN tre los exponentes de Hurst, estimados por las técnicas Lagrangiana y Euleriana, muestra que a medida que el nivel de simetría aumenta, el transporte se vuelve fuertemente subdifusivo. Aunque, la validez del modelo fraccionario en sí mismo se vuelve dudosa en los casos limítes de alta y baja simetría.El trabajo presentado en esta tesis puede extenderse naturalmente para estudiar la validez del modelo de transporte fraccionario en otros tipos de campos magnéticos confinantes y estudiar varios efectos relacionados con las partículas α, como colisiones, perfiles de nacimiento de las partículas α, etc.

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“…This transport is of special relevance for stellarator geometries, whose non-axisymmetric character strongly impacts particle dynamics. In fact, the confinement of α-particles is one of the most critical points in the design of a viable stellarator fusion reactor 7,[31][32][33][34] .…”

Section: Introductionmentioning

confidence: 99%

Non-diffusive nature of collisionless α -particle transport: Dependence on toroidal symmetry in stellarator geometries

et al. 2020

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An adequate confinement of α-particles is fundamental for the operation of future fusion powered reactors. An even more critical situation arises for stellarator devices, whose complex magnetic geometry can substantially increase α-particle losses. A traditional approach to transport evaluation is based on a diffusive paradigm, however, a growing body of literature presents a considerable amount of examples and arguments towards the validity of non-diffusive transport models for fusion plasmas, particularly in cases of turbulent driven transport [ R. Sánchez and D.E. Newman, Plasma Phys. Control. Fusion 57 123002 (2015)]. Likewise, a recent study of collisionless α-particle transport in quasi-toroidally symmetric stellarators [A. Gogoleva et al., Nucl. Fusion 60 056009 (2020)] puts the diffusive framework into question. In search of a better transport model, we numerically characterized and quantified the underlying nature of transport of the resulting α-particle trajectories by employing a whole set of tools, imported from fractional transport theory. The study was carried out for a set of five configurations to establish the relation between the level of magnetic field toroidal symmetry and the fractional transport coefficients, i.e. the Hurst H, the spatial α and the temporal β exponents, each being a merit of non-diffusive transport. The results indicate that the α-particle ripple-enhanced transport is non-Gaussian and non-Markovian. Moreover, as the degree of quasi-toroidal symmetry increases, it becomes strongly subdiffusive. Although, the validity of the fractional model itself becomes doubtful in the limiting high and low symmetry cases.

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Comparative collisionless alpha particle confinement in stellarator reactors with the XGC gyrokinetic code

Cited by 13 publications

References 37 publications

Nonlinear gyrokinetic PIC simulations in stellarators with the code EUTERPE

Nonlinear gyrokinetic PIC simulations in stellarators with the code EUTERPE

Statistical description of collisionless α-particle transport in cases of broken symmetry: from ITER to quasi-toroidally symmetric stellarators

Non-diffusive nature of collisionless α -particle transport: Dependence on toroidal symmetry in stellarator geometries

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