Global gyrokinetic simulations of TEM microturbulence

Vernay, T.; Brunner, S.; Villard, L.; McMillan, B. F.; Jolliet, S.; Bottino, A.; Görler, T.; Jenko, F.

doi:10.1088/0741-3335/55/7/074016

Cited by 19 publications

(14 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…25 Several studies have shown that those parameters can present TEM modes well at wavelength, k θ ρ i 1. 25,26 ETG modes can also be linearly unstable for these parameters at shorter wavelengths, with poloidal wave number k θ ρ i 1. 26 Although their existence can influence the electron heat flux significantly, their impact on α particle transport is expected to be negligible due to the following reasons.…”

Section: Results From Linear Simulationsmentioning

confidence: 99%

“…25,26 ETG modes can also be linearly unstable for these parameters at shorter wavelengths, with poloidal wave number k θ ρ i 1. 26 Although their existence can influence the electron heat flux significantly, their impact on α particle transport is expected to be negligible due to the following reasons. With large spatial scale separation between α particle orbit and ETG wavelength, even stronger orbitaveraging and the frequency detuning 10,11 would occur compared to those for TEM.…”

Section: Results From Linear Simulationsmentioning

confidence: 99%

See 1 more Smart Citation

Gyrokinetic study of slowing-down α particles transport due to trapped electron mode turbulence

et al. 2018

View full text Add to dashboard Cite

Transport of α particles due to trapped electron mode (TEM) turbulence is investigated from nonlinear and quasilinear gyrokinetic simulations. We consider both slowing-down and Maxwellian distribution functions for α particles, and identify and compare diffusive and convective parts of α particle transport as a function of the α particle's energy normalized to the background plasma temperature. We find that TEM induces much lower transport of energetic α particles such as fusion products than that of thermal Helium ions in the trace limit. This disparity from our study is found to be even greater than that reported previously for ion temperature gradient (ITG) mode [C. Angioni and A.G. Peeters, Phys.Plasmas.

show abstract

Section: Results From Linear Simulationsmentioning

confidence: 99%

Section: Results From Linear Simulationsmentioning

confidence: 99%

Gyrokinetic study of slowing-down α particles transport due to trapped electron mode turbulence

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Moreover, trapped electron modes (TEM) could be destabilized, in particular once ITGs are stabilized by ZF. First nonlinear TEM results in circular plasmas at low 1/ρ * [30,31] indicate that TEMs are less effectively suppressed by ZF shearing than ITG. Second, ion-ion collisions are known to damp the ZF, resulting in nonzero turbulent transport in the 'Dimits shift' region [20].…”

Section: Resultsmentioning

confidence: 99%

Global gyrokinetic ion temperature gradient turbulence simulations of ITER

Villard

Angelino

Bottino

et al. 2013

Plasma Phys. Control. Fusion

Self Cite

View full text Add to dashboard Cite

Global gyrokinetic simulations of ion temperature gradient (ITG) driven turbulence in an ideal MHD ITER equilibrium plasma are performed with the ORB5 code. The noise control and field-aligned Fourier filtering procedures implemented in ORB5 are essential in obtaining numerically healthy results with a reasonable amount of computational effort: typical simulations require 10 9 grid points, 10 9 particles and, despite a particle per cell ratio of unity, achieve a signal to noise ratio larger than 50. As compared with a circular concentric configuration with otherwise similar parameters (same ρ * = 1/720), the effective heat diffusivity is considerably reduced for the ITER MHD equilibrium. A self-organized radial structure appears, with long-lived zonal flows (ZF), modulating turbulence heat transport and resulting in a corrugated temperature gradient profile. The ratio of long-lived ZF to the fluctuating ZF is markedly higher for the ITER MHD equilibrium as compared with circular configurations, thereby producing a more effective ITG turbulence suppression, in spite of a higher linear growth rate. As a result, the nonlinear critical temperature gradient, R/L T crit,NL , is about twice the linear critical temperature gradient, R/L T crit,lin. Moreover, the heat transport stiffness above the nonlinear threshold is considerably reduced as compared with circular cases. Plasma elongation is probably one of the essential causes of this behaviour: indeed, undamped ZF residual levels and geodesic acoustic mode damping are both increasing with elongation. Other possible causes of the difference, such as magnetic shear profile effects, are also investigated.

show abstract

“…2004, 2006; Vernay et al. 2013). The NEMORB gyrokinetic model, in the electrostatic limit, is based on the gyrokinetic Vlasov–Poisson system of equations described in the previous section: where is a collision operator and is a heat source term.…”

Section: Resultsmentioning

confidence: 99%

“…The linearised field equations, the polarisation equation and the parallel Ampère's law are discretised using B-splines. The code is based on straight-field-line coordinates and includes collision operators (Vernay et al 2010), shaped MHD equilibria and a hybrid model for the trapped electrons (Bottino et al 2004(Bottino et al , 2006Vernay et al 2013). The NEMORB gyrokinetic model, in the electrostatic limit, is based on the gyrokinetic Vlasov-Poisson system of equations described in the previous section:…”

Section: Resultsmentioning

confidence: 99%

Monte Carlo particle-in-cell methods for the simulation of the Vlasov–Maxwell gyrokinetic equations

2015

View full text Add to dashboard Cite

The particle-in-cell (PIC) algorithm is the most popular method for the discretisation of the general 6D Vlasov–Maxwell problem and it is widely used also for the simulation of the 5D gyrokinetic equations. The method consists of coupling a particle-based algorithm for the Vlasov equation with a grid-based method for the computation of the self-consistent electromagnetic fields. In this review we derive a Monte Carlo PIC finite-element model starting from a gyrokinetic discrete Lagrangian. The variations of the Lagrangian are used to obtain the time-continuous equations of motion for the particles and the finite-element approximation of the field equations. The Noether theorem for the semi-discretised system implies a certain number of conservation properties for the final set of equations. Moreover, the PIC method can be interpreted as a probabilistic Monte Carlo like method, consisting of calculating integrals of the continuous distribution function using a finite set of discrete markers. The nonlinear interactions along with numerical errors introduce random effects after some time. Therefore, the same tools for error analysis and error reduction used in Monte Carlo numerical methods can be applied to PIC simulations.

show abstract

Global gyrokinetic simulations of TEM microturbulence

Cited by 19 publications

References 39 publications

Gyrokinetic study of slowing-down α particles transport due to trapped electron mode turbulence

Gyrokinetic study of slowing-down α particles transport due to trapped electron mode turbulence

Global gyrokinetic ion temperature gradient turbulence simulations of ITER

Monte Carlo particle-in-cell methods for the simulation of the Vlasov–Maxwell gyrokinetic equations

Contact Info

Product

Resources

About