A minimal collision operator for implementing neoclassical transport in gyrokinetic simulations

2008 ◽  
Author(s):  
X. Garbet ◽  
G. Dif-Pradalier ◽  
C. Nguyen ◽  
P. Angelino ◽  
Y. Sarazin ◽  
...  
Keyword(s):  
Collision Operator ◽  
Neoclassical Transport ◽  
Gyrokinetic Simulations

scholarly journals Gyrokinetic simulations of neoclassical transport using a minimal collision operator

2008 ◽  
Author(s):  
G. Dif-Pradalier ◽  
V. Grandgirard ◽  
Y. Sarazin ◽  
X. Garbet ◽  
Ph. Ghendrih ◽  
...  
Keyword(s):  
Collision Operator ◽  
Neoclassical Transport ◽  
Gyrokinetic Simulations

Symmetries of and entropy production by transport in toroidal confinement systems

1998 ◽  
Vol 59 (4) ◽  
pp. 695-706 ◽  
Author(s):  
H. SUGAMA ◽  
W. HORTON
Keyword(s):  
Entropy Production ◽  
Transport Process ◽  
Collision Operator ◽  
Positive Definite ◽  
Anomalous Transport ◽  
The Self ◽  
Entropy Production Rate ◽  
Onsager Symmetry ◽  
Neoclassical Transport ◽  
Linearized Collision Operator

A synthesized formulation of classical, neoclassical and anomalous transport in toroidal confinement systems with electromagnetic fluctuations and large mean flows is presented. The positive-definite entropy production rate and the conjugate flux–force pairs are rigorously defined for each transport process. The Onsager symmetries of the classical and neoclassical transport matrices are derived from the self-adjointness of the linearized collision operator. The linear gyrokinetic equation with given electromagnetic fluctuations determines the anomalous fluxes with the quasilinear anomalous transport matrix, which satisfies the Onsager symmetry.

Improved Unlike-Particle Collision Operator for delta-f Drift-Kinetic Particle Simulations

2011 ◽  
Vol 9 (2) ◽  
pp. 231-239
Author(s):  
R. A. Kolesnikov ◽  
W. X. Wang ◽  
F. L. Hinton
Keyword(s):  
Collision Operator ◽  
Particle Simulation ◽  
Particle Collision ◽  
Nonlocal Effects ◽  
Toroidal Plasmas ◽  
Neoclassical Transport ◽  
Particle Simulations ◽  
Impurity Ion ◽  
Ion Species ◽  
Particle Operator

AbstractPlasmas in modern tokamak experiments contain a significant fraction of impurity ion species in addition to main deuterium background. A new unlike-particle collision operator for δf particle simulation has been developed to study the nonlocal effects of impurities due to finite ion orbits on neoclassical transport in toroidal plasmas. A new algorithm for simulation of cross-collisions between different ion species includes test-particle and conserving field-particle operators. An improved field-particle operator is designed to exactly enforce conservation of number, momentum and energy.

Neoclassical transport simulations with an improved model collision operator

2021 ◽  
Vol 28 (6) ◽  
pp. 064501
Author(s):  
S. Matsuoka ◽  
H. Sugama ◽  
Y. Idomura
Keyword(s):  
Collision Operator ◽  
Neoclassical Transport ◽  
Model Collision ◽  
Improved Model

scholarly journals Benchmark of a new multi-ion-species collision operator for δf Monte Carlo neoclassical simulation

2020 ◽  
Vol 255 ◽  
pp. 107249 ◽  
Author(s):  
Shinsuke Satake ◽  
Motoki Nataka ◽  
Theerasarn Pianpanit ◽  
Hideo Sugama ◽  
Masanori Nunami ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Collision Operator ◽  
Ion Species

Diffusion limit of a Boltzmann–Poisson system with nonlinear equilibrium state

2019 ◽  
Vol 16 (01) ◽  
pp. 131-156
Author(s):  
Lanoir Addala ◽  
Mohamed Lazhar Tayeb
Keyword(s):  
Nonlinear Diffusion ◽  
Collision Operator ◽  
Nonlinear Diffusion Equation ◽  
One Dimension ◽  
Diffusion Limit ◽  
Poisson System ◽  
Nonlinear Relaxation ◽  
Contraction Property ◽  
Hilbert Expansion ◽  
Nonlinear Equilibrium

The diffusion approximation for a Boltzmann–Poisson system is studied. Nonlinear relaxation type collision operator is considered. A relative entropy is used to prove useful [Formula: see text]-estimates for the weak solutions of the scaled Boltzmann equation (coupled to Poisson) and to prove the convergence of the solution toward the solution of a nonlinear diffusion equation coupled to Poisson. In one dimension, a hybrid Hilbert expansion and the contraction property of the operator allow to exhibit a convergence rate.

scholarly journals Shock Structure and Relaxation in the Multi-Component Mixture of Euler Fluids

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 955
Author(s):  
Damir Madjarević ◽  
Milana Pavić-Čolić ◽  
Srboljub Simić
Keyword(s):  
Relaxation Times ◽  
Thermal Relaxation ◽  
Collision Operator ◽  
Weak Form ◽  
Shock Structure ◽  
Theory Approach ◽  
Component Mixture ◽  
Single Temperature ◽  
The Difference ◽  
Euler Fluids

The shock structure problem is studied for a multi-component mixture of Euler fluids described by the hyperbolic system of balance laws. The model is developed in the framework of extended thermodynamics. Thanks to the equivalence with the kinetic theory approach, phenomenological coefficients are computed from the linearized weak form of the collision operator. Shock structure is analyzed for a three-component mixture of polyatomic gases, and for various combinations of parameters of the model (Mach number, equilibrium concentrations and molecular mass ratios). The analysis revealed that three-component mixtures possess distinguishing features different from the binary ones, and that certain behavior may be attributed to polyatomic structure of the constituents. The multi-temperature model is compared with a single-temperature one, and the difference between the mean temperatures of the mixture are computed. Mechanical and thermal relaxation times are computed along the shock profiles, and revealed that the thermal ones are smaller in the case discussed in this study.

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