Developing efficient MD method for strongly coupled plasmas

ORAL

Abstract

Molecular dynamics (MD) is one of the most intuitive techniques to analyze a many-body system such as a plasma. It considers interactions of all particle pairs in the system and solves Newton's equations of motion to calculate statistical quantities such as temperature. A great strength of MD is adequately analyzing statistical phenomena of the system which we can't analytically. For example, we can observe the time evolution of temperatures of various species in a plasma and calculate their equilibration time. A weakness is a huge amount of computational effort, $O(N^{2})$ for $N$ particles, to compute all interactions. Several efficient methods are developed: The Ewald sum reduces the computational effort to $O(N^{3/2})$, the particle-particle/particle-mesh method of Eastwood and Hockney to $O(N\log N)$, and the fast multipole method of Greengard and Rokhlin to $O(N)$. In this work, we develop a hybrid method that computes particle-particle interactions for up to neighboring cells and adopts the fast multipole method for distant cells. The hybrid method significantly reduces the computational effort for a large number of particles, $N>5\times10^{4}$. We present MD simulation results from studying temperature equilibration of two species for a strongly coupled plasma.

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Authors

  • Jawon Jo

    Department of Physics, Utah State University, Logan, Utah, 84322

  • Barry Ritchie

    University of New Mexico, Ion Linac Systems, Tech-X Corporation, Los Alamos National Laboratory, Ronald Reagan UCLA Medical Center, Brigham Young University, Brigham Young University - Provo, United States Air Force Academy, university of Michigan, SISSA, Trieste, Stanford University, Worcester Polytechnic Institute, Grinnell College, Department of Physics, Arizona State University, Brookhaven National Laboratory, University of Southern California, Argonne National Laboratory, Department of Electrical and Computer Engineering, University of New Mexico, Department of Electrical and Computer Engineering and Department of Mechanical Engineering, University of New Mexico, Lock Haven University, Illinois State University, Department of Physics, Utah State University, Logan, Utah, 84322, Department of Physics, New Mexico State University, Las Cruces, New Mexico 88003, USA, Department of Materials, Devices, and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA, Kyoto University, University of Guadalajara, University of Florida, Embry-Riddle Aeronautical University, Air Force Research Laboratory, Space Vehicles Directorate, Assurance Technology Corporation, Carlisle, MA, Georgia Tech Research Institute, Atlanta, GA, Utah State University, Georgia Institute of Technology, University of Tennessee, Knoxville, Arizona State University, Department of Physics, United States Air Force Academy, 80840 USAFA, CO, USA, Shaffer Consulting Inc, Max Planck Institute for Astrophysics, Harvard University, Max Planck Institute for Gravitational Physics, Albert Einstein Institute, ASU

  • Barry Ritchie

    University of New Mexico, Ion Linac Systems, Tech-X Corporation, Los Alamos National Laboratory, Ronald Reagan UCLA Medical Center, Brigham Young University, Brigham Young University - Provo, United States Air Force Academy, university of Michigan, SISSA, Trieste, Stanford University, Worcester Polytechnic Institute, Grinnell College, Department of Physics, Arizona State University, Brookhaven National Laboratory, University of Southern California, Argonne National Laboratory, Department of Electrical and Computer Engineering, University of New Mexico, Department of Electrical and Computer Engineering and Department of Mechanical Engineering, University of New Mexico, Lock Haven University, Illinois State University, Department of Physics, Utah State University, Logan, Utah, 84322, Department of Physics, New Mexico State University, Las Cruces, New Mexico 88003, USA, Department of Materials, Devices, and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA, Kyoto University, University of Guadalajara, University of Florida, Embry-Riddle Aeronautical University, Air Force Research Laboratory, Space Vehicles Directorate, Assurance Technology Corporation, Carlisle, MA, Georgia Tech Research Institute, Atlanta, GA, Utah State University, Georgia Institute of Technology, University of Tennessee, Knoxville, Arizona State University, Department of Physics, United States Air Force Academy, 80840 USAFA, CO, USA, Shaffer Consulting Inc, Max Planck Institute for Astrophysics, Harvard University, Max Planck Institute for Gravitational Physics, Albert Einstein Institute, ASU