### Abstract

Hybrid integration and acceleration techniques are used to speed up the electron guiding centre orbit calculations in a toroidal axisymmetric magnetized plasma in the presence of a dc electric field. Acceleration of the computation is introduced to bridge the gap between the two different time scales: the rapid circulations of the electron around the magnetic axis and the relatively infrequent collisions and slow response to the electric field. The constants of motion method is utilized in correcting the particle position after each guiding centre step, which makes long time steps in the integration possible. The method described is applied to the simulation of reverse runaway electrons in a tokamak plasma. It is shown that in some cases fairly large average acceleration factors (100–10000) are acceptable: the statistics for an ensemble of electrons remain correct and the transition of a single electron through the trapped orbit velocity cone is properly described. A good agreement is found with 2-D Fokker-Planck calculations in the straight cylinder approximation for a cold plasma. The finite temperature and toroidal effects on the reverse runaway rate are calculated, and the adverse effects of runaway electrons on current ramp-up in tokamaks are discussed.

Original language | English |
---|---|

Pages (from-to) | 215 - 230 |

Number of pages | 16 |

Journal | Computer Physics Communications |

Volume | 76 |

Issue number | 2 |

DOIs | |

Publication status | Published - 1993 |

MoE publication type | A1 Journal article-refereed |

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### Cite this

*Computer Physics Communications*,

*76*(2), 215 - 230. https://doi.org/10.1016/0010-4655(93)90133-W

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*Computer Physics Communications*, vol. 76, no. 2, pp. 215 - 230. https://doi.org/10.1016/0010-4655(93)90133-W

**Monte Carlo simulation of runaway electrons in a toroidal geometry.** / Heikkinen, Jukka (Corresponding Author); Sipilä, Seppo; Pättikangas, Timo.

Research output: Contribution to journal › Article › Scientific › peer-review

TY - JOUR

T1 - Monte Carlo simulation of runaway electrons in a toroidal geometry

AU - Heikkinen, Jukka

AU - Sipilä, Seppo

AU - Pättikangas, Timo

N1 - Project code: ydi0030

PY - 1993

Y1 - 1993

N2 - Hybrid integration and acceleration techniques are used to speed up the electron guiding centre orbit calculations in a toroidal axisymmetric magnetized plasma in the presence of a dc electric field. Acceleration of the computation is introduced to bridge the gap between the two different time scales: the rapid circulations of the electron around the magnetic axis and the relatively infrequent collisions and slow response to the electric field. The constants of motion method is utilized in correcting the particle position after each guiding centre step, which makes long time steps in the integration possible. The method described is applied to the simulation of reverse runaway electrons in a tokamak plasma. It is shown that in some cases fairly large average acceleration factors (100–10000) are acceptable: the statistics for an ensemble of electrons remain correct and the transition of a single electron through the trapped orbit velocity cone is properly described. A good agreement is found with 2-D Fokker-Planck calculations in the straight cylinder approximation for a cold plasma. The finite temperature and toroidal effects on the reverse runaway rate are calculated, and the adverse effects of runaway electrons on current ramp-up in tokamaks are discussed.

AB - Hybrid integration and acceleration techniques are used to speed up the electron guiding centre orbit calculations in a toroidal axisymmetric magnetized plasma in the presence of a dc electric field. Acceleration of the computation is introduced to bridge the gap between the two different time scales: the rapid circulations of the electron around the magnetic axis and the relatively infrequent collisions and slow response to the electric field. The constants of motion method is utilized in correcting the particle position after each guiding centre step, which makes long time steps in the integration possible. The method described is applied to the simulation of reverse runaway electrons in a tokamak plasma. It is shown that in some cases fairly large average acceleration factors (100–10000) are acceptable: the statistics for an ensemble of electrons remain correct and the transition of a single electron through the trapped orbit velocity cone is properly described. A good agreement is found with 2-D Fokker-Planck calculations in the straight cylinder approximation for a cold plasma. The finite temperature and toroidal effects on the reverse runaway rate are calculated, and the adverse effects of runaway electrons on current ramp-up in tokamaks are discussed.

U2 - 10.1016/0010-4655(93)90133-W

DO - 10.1016/0010-4655(93)90133-W

M3 - Article

VL - 76

SP - 215

EP - 230

JO - Computer Physics Communications

JF - Computer Physics Communications

SN - 0010-4655

IS - 2

ER -