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Title: An implicit δf particle-in-cell method with sub-cycling and orbit averaging for Lorentz ions

Abstract

A second order implicit δf Lorentz ion hybrid model with sub-cycling and orbit averaging has been developed to study low-frequency, quasi-neutral plasmas. Models using the full Lorentz force equations of motion for ions may be useful for verifying gyrokinetic ion simulation models in applications where higher order terms may be important. In the presence of a strong external magnetic field, previous Lorentz ion models are limited to simulating very short time scales due to the small time step required for resolving the ion gyromotion. Here, we use a simplified model for ion Landau damped ion acoustic waves in a uniform magnetic field as a test bed for developing efficient time stepping methods to be used with the Lorentz ion hybrid model. A detailed linear analysis of the model is derived to validate simulations and to examine the significance of ion Bernstein waves in the Lorentz ion model. Linear analysis of a gyrokinetic ion model is also performed, and excellent agreement with the dispersion results from the Lorentz ion model is demonstrated for the ion acoustic wave. The sub-cycling/orbit averaging algorithm is shown to produce accurate finite-Larmor-radius effects using large macro-time steps sizes, and numerical damping of high frequency fluctuations canmore » be achieved by formulating the field model in terms of the perturbed flux density. Furthermore, a CPU–GPU implementation of the sub-cycling/orbit averaging is presented and is shown to achieve a significant speedup over an equivalent serial code.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Univ. of Colorado, Boulder, CO (United States); UT-Battelle LLC/ORNL, Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1565432
DOE Contract Number:  
FC02-08ER54971; AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Journal of Computational Physics
Additional Journal Information:
Journal Volume: 316; Journal Issue: C; Journal ID: ISSN 0021-9991
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
Computer Science; Physics

Citation Formats

Sturdevant, Benjamin J., Parker, Scott E., Chen, Yang, and Hause, Benjamin B. An implicit δf particle-in-cell method with sub-cycling and orbit averaging for Lorentz ions. United States: N. p., 2016. Web. doi:10.1016/j.jcp.2016.04.036.
Sturdevant, Benjamin J., Parker, Scott E., Chen, Yang, & Hause, Benjamin B. An implicit δf particle-in-cell method with sub-cycling and orbit averaging for Lorentz ions. United States. https://doi.org/10.1016/j.jcp.2016.04.036
Sturdevant, Benjamin J., Parker, Scott E., Chen, Yang, and Hause, Benjamin B. 2016. "An implicit δf particle-in-cell method with sub-cycling and orbit averaging for Lorentz ions". United States. https://doi.org/10.1016/j.jcp.2016.04.036.
@article{osti_1565432,
title = {An implicit δf particle-in-cell method with sub-cycling and orbit averaging for Lorentz ions},
author = {Sturdevant, Benjamin J. and Parker, Scott E. and Chen, Yang and Hause, Benjamin B.},
abstractNote = {A second order implicit δf Lorentz ion hybrid model with sub-cycling and orbit averaging has been developed to study low-frequency, quasi-neutral plasmas. Models using the full Lorentz force equations of motion for ions may be useful for verifying gyrokinetic ion simulation models in applications where higher order terms may be important. In the presence of a strong external magnetic field, previous Lorentz ion models are limited to simulating very short time scales due to the small time step required for resolving the ion gyromotion. Here, we use a simplified model for ion Landau damped ion acoustic waves in a uniform magnetic field as a test bed for developing efficient time stepping methods to be used with the Lorentz ion hybrid model. A detailed linear analysis of the model is derived to validate simulations and to examine the significance of ion Bernstein waves in the Lorentz ion model. Linear analysis of a gyrokinetic ion model is also performed, and excellent agreement with the dispersion results from the Lorentz ion model is demonstrated for the ion acoustic wave. The sub-cycling/orbit averaging algorithm is shown to produce accurate finite-Larmor-radius effects using large macro-time steps sizes, and numerical damping of high frequency fluctuations can be achieved by formulating the field model in terms of the perturbed flux density. Furthermore, a CPU–GPU implementation of the sub-cycling/orbit averaging is presented and is shown to achieve a significant speedup over an equivalent serial code.},
doi = {10.1016/j.jcp.2016.04.036},
url = {https://www.osti.gov/biblio/1565432}, journal = {Journal of Computational Physics},
issn = {0021-9991},
number = C,
volume = 316,
place = {United States},
year = {Fri Jul 01 00:00:00 EDT 2016},
month = {Fri Jul 01 00:00:00 EDT 2016}
}