scholarly journals Improved Krook model collision operator for trapped-particle mode calculations

1981 ◽  
Author(s):  
J. DeLucia ◽  
G. Rewoldt
Keyword(s):  
Collision Operator ◽  
Model Collision

scholarly journals Evolution Equation and Transport Coefficients of Swarms in Initial Relaxation Processes

1987 ◽  
Vol 40 (3) ◽  
pp. 367 ◽  
Author(s):  
Keiichi Kondo
Keyword(s):  
Evolution Equation ◽  
Transport Coefficients ◽  
Collision Operator ◽  
Operator Method ◽  
Time Dependent ◽  
Relaxation Processes ◽  
Projection Operator Method ◽  
Model Collision ◽  
The Difference ◽  
Dependent Transport

The problem of a swarm approaching the hydrodynamic regime is studied by using the projection operator method. An evolution equation for the density and the related time-dependent transport coefficient are derived. The effects of the initial condition on the transport characteristics of a swarm are separated from the intrinsic evolution of the swarms, and the difference from the continuity equation with time-dependent transport coefficients introduced by Tagashira et al. (1977, 1978) is discussed. To illustrate this method, calculations on the relaxation model collision operator have been carried out. The results are found to agree with the analysis by Robson (1975).

scholarly journals Improved linearized model collision operator for the highly collisional regime

2019 ◽  
Vol 26 (10) ◽  
pp. 102108 ◽  
Author(s):  
H. Sugama ◽  
S. Matsuoka ◽  
S. Satake ◽  
M. Nunami ◽  
T.-H. Watanabe
Keyword(s):  
Collision Operator ◽  
Model Collision ◽  
Linearized Model ◽  
Collisional Regime

Velocity Fourier transform solution of a model collision operator

1979 ◽  
Vol 22 (9) ◽  
pp. 1647 ◽  
Author(s):  
Peter J. Catto
Keyword(s):  
Fourier Transform ◽  
Collision Operator ◽  
Model Collision

A Model Collision Operator for Orbit Averaged Monte Carlo Codes

2006 ◽  
Author(s):  
T. Hellsten ◽  
T. Johnson
Keyword(s):  
Monte Carlo ◽  
Collision Operator ◽  
Model Collision

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

A theorem concerning the asymptotic collision operator

1973 ◽  
Vol 59 (1) ◽  
pp. 642-652
Author(s):  
Peter Murray Allen
Keyword(s):  
Collision Operator

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.

Moments of the Boltzmann collision operator for Coulomb interactions

2021 ◽  
Vol 28 (7) ◽  
pp. 072113
Author(s):  
Jeong-Young Ji ◽  
Min Uk Lee ◽  
Eric D. Held ◽  
Gunsu S. Yun
Keyword(s):  
Collision Operator ◽  
Coulomb Interactions ◽  
Boltzmann Collision Operator
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