Abstract Details
Abstracts
Author: Fu Yichen
Requested Type: Poster
Submitted: 2025-03-05 15:22:13
Co-authors:
Contact Info:
Lawrence Livermore National Laboratory
7000 East Ave
Livermore, California 94550
United States
Abstract Text:
Coulomb collision is a fundamental diffusion process in plasmas that can be described by the Landau-Fokker-Planck (LFP) equation or the stochastic differential equation (SDE). While energy and momentum are conserved exactly in the LFP equation, they are conserved only on average by the conventional corresponding SDEs, suggesting that the underlying stochastic process may not be well-defined by such SDEs. In this study [1], we derive new SDEs with exact conservation laws for the Coulomb collision by factorizing the collective effect of field particles into individual particles and enforcing Newton’s third law. These SDEs, when interpreted in the Stratonovich sense, have a particularly simple form that represents pure diffusion between particles without drag. Numerical algorithms that preserve discrete conservation laws are developed and benchmarked in various relaxation processes. Techniques to reduce computational complexity are also discussed.
[1] Fu, Yichen, et al. Physical Review E 111.2 (2025): 025211.
This research was supported by the US Department of Energy through Contracts DE-AC52- 07NA27344 (LLNL), DE-AC02-09CH1146 (PPPL), and LLNL-ABS-872571. This work was also supported by the LLNL-LDRD Program under Project No. 23-ERD007.
Characterization: 4.0
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