点击次数：

DOI码：10.1088/1741-4326/aad2a5

发表刊物：Nuclear Fusion

关键字：collisionless pitch-angle scattering, magnetic moment, runaway electron

摘要：Recently, the validity of the guiding-center approach to model relativistic runaway electrons in tokamaks has been challenged by full-orbit simulations that demonstrate the breakdown of the standard magnetic moment conservation. In this paper, we derive a new expression for the magnetic moment of relativistic runaway electrons with , which is conserved significantly better than the standard one. The new result includes one of the second-order corrections in the standard guiding-center theory which, in case of runaway electrons with , can peculiarly be of the same order as the lowest-order term. The better conservation of the new magnetic moment also explains the collisionless pitch-angle-scattering effect observed in full-orbit simulations since it allows momentum transfer between the perpendicular and parallel directions when the runaway electron is accelerated by an electric field. While the derivation of the second-order correction to the magnetic moment in general case would require the full extent of the relativistic second-order guiding-center theory, we exploit the Lie-perturbation method at the limit which simplifies the computations significantly. Consequently, we present the corresponding guiding-center equations applicable to runaway electrons.

合写作者：Chang Liu,Hong Qin,Eero Hirvijokl,Yulei Wang,Jian Liu

学科门类：理学

卷号：58

期号：10

页面范围：106018

是否译文：否

发表时间：2018-08-03

收录刊物：SCI

发布期刊链接：https://www.osti.gov/biblio/1460954