### Abstract

If the collisional time scale for Coulomb collisions is comparable to the characteristic time scales for a plasma, then simulation of Coulombcollisions may be important for computation of kinetic plasma dynamics. This can be a computational bottleneck because of the large number of simulated particles and collisions (or phase-space resolution requirements i continuum algorithms), as well as the wide range of collision rates over the velocity distribution function. This paper considers Monte Carlo simulation of Coulomb collisions using the binary collision models of Takizuka and Abe and of Nanbu. It presents a hybrid method for accelerating the computation of Coulomb collisions. The hybrid method represents the velocity distribution function as a combination of a thermal component (a Maxwellian distribution) and a kinetic component (a set of discrete particles). Collisions between particles from the thermal component preserve the Maxwellian; collisions between particles from the kinetic component are performed using the method of Takizuka and Abe or of Nanbu. Collisions between the kinetic and thermal components are performed by sampling a particle from the thermal component and selecting a particle from the kinetic component. Particles are also transferred between the two components according to thermalization and dethermalization probabilities, which are functions of phase space.

Original language | English (US) |
---|---|

Pages (from-to) | 865-887 |

Number of pages | 23 |

Journal | Multiscale Modeling and Simulation |

Volume | 7 |

Issue number | 2 |

DOIs | |

State | Published - 2008 |

### Fingerprint

### Keywords

- Bump on tail
- Coulomb collisions
- Hybrid method
- Plasma
- Simulation
- Thermalization

### ASJC Scopus subject areas

- Chemistry(all)
- Modeling and Simulation
- Ecological Modeling
- Physics and Astronomy(all)
- Computer Science Applications

### Cite this

*Multiscale Modeling and Simulation*,

*7*(2), 865-887. https://doi.org/10.1137/070704939

**A hybrid method for accelerated simulation of coulomb collisions in a plasma.** / Caflisch, Russel; Wang, Chiaming; Dimarco, Giacomo; Cohen, Bruce; Dimits, Andris.

Research output: Contribution to journal › Article

*Multiscale Modeling and Simulation*, vol. 7, no. 2, pp. 865-887. https://doi.org/10.1137/070704939

}

TY - JOUR

T1 - A hybrid method for accelerated simulation of coulomb collisions in a plasma

AU - Caflisch, Russel

AU - Wang, Chiaming

AU - Dimarco, Giacomo

AU - Cohen, Bruce

AU - Dimits, Andris

PY - 2008

Y1 - 2008

N2 - If the collisional time scale for Coulomb collisions is comparable to the characteristic time scales for a plasma, then simulation of Coulombcollisions may be important for computation of kinetic plasma dynamics. This can be a computational bottleneck because of the large number of simulated particles and collisions (or phase-space resolution requirements i continuum algorithms), as well as the wide range of collision rates over the velocity distribution function. This paper considers Monte Carlo simulation of Coulomb collisions using the binary collision models of Takizuka and Abe and of Nanbu. It presents a hybrid method for accelerating the computation of Coulomb collisions. The hybrid method represents the velocity distribution function as a combination of a thermal component (a Maxwellian distribution) and a kinetic component (a set of discrete particles). Collisions between particles from the thermal component preserve the Maxwellian; collisions between particles from the kinetic component are performed using the method of Takizuka and Abe or of Nanbu. Collisions between the kinetic and thermal components are performed by sampling a particle from the thermal component and selecting a particle from the kinetic component. Particles are also transferred between the two components according to thermalization and dethermalization probabilities, which are functions of phase space.

AB - If the collisional time scale for Coulomb collisions is comparable to the characteristic time scales for a plasma, then simulation of Coulombcollisions may be important for computation of kinetic plasma dynamics. This can be a computational bottleneck because of the large number of simulated particles and collisions (or phase-space resolution requirements i continuum algorithms), as well as the wide range of collision rates over the velocity distribution function. This paper considers Monte Carlo simulation of Coulomb collisions using the binary collision models of Takizuka and Abe and of Nanbu. It presents a hybrid method for accelerating the computation of Coulomb collisions. The hybrid method represents the velocity distribution function as a combination of a thermal component (a Maxwellian distribution) and a kinetic component (a set of discrete particles). Collisions between particles from the thermal component preserve the Maxwellian; collisions between particles from the kinetic component are performed using the method of Takizuka and Abe or of Nanbu. Collisions between the kinetic and thermal components are performed by sampling a particle from the thermal component and selecting a particle from the kinetic component. Particles are also transferred between the two components according to thermalization and dethermalization probabilities, which are functions of phase space.

KW - Bump on tail

KW - Coulomb collisions

KW - Hybrid method

KW - Plasma

KW - Simulation

KW - Thermalization

UR - http://www.scopus.com/inward/record.url?scp=55149084172&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=55149084172&partnerID=8YFLogxK

U2 - 10.1137/070704939

DO - 10.1137/070704939

M3 - Article

VL - 7

SP - 865

EP - 887

JO - Multiscale Modeling and Simulation

JF - Multiscale Modeling and Simulation

SN - 1540-3459

IS - 2

ER -