Skip navigation
Please use this identifier to cite or link to this item:
Title: Simulating pitch angle scattering using an explicitly solvable energy-conserving algorithm
Contributors: Zhang, Xin
Fu, Yichen
Qin, Hong
U. S. Department of Energy
Issue Date: Sep-2020
Publisher: Princeton Plasma Physics Laboratory, Princeton University
Related Publication: Physical Review E
Abstract: Particle distribution functions evolving under the Lorentz operator can be simulated with the Langevin equation for pitch angle scattering. This approach is frequently used in particle based Monte-Carlo simulations of plasma collisions, among others. However, most numerical treatments do not guarantee energy conservation, which may lead to unphysical artifacts such as numerical heating and spectra distortions. We present a novel structure-preserving numerical algorithm for the Langevin equation for pitch angle scattering. Similar to the well-known Boris algorithm, the proposed numerical scheme takes advantage of the structure-preserving properties of the Cayley transform when calculating the velocity-space rotations. The resulting algorithm is explicitly solvable, while preserving the norm of velocities down to machine precision. We demonstrate that the method has the same order of numerical convergence as the traditional stochastic Euler-Maruyama method.
Appears in Collections:NSTX-U

Files in This Item:
File Description SizeFormat 
README.txt403 BTextView/Download
ARK_DATA.zip805.47 kBUnknownView/Download

Items in Dataspace are protected by copyright, with all rights reserved, unless otherwise indicated.