Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Conservative discontinuous Galerkin schemes for nonlinear Dougherty–Fokker–Planck collision operators

Journal Article · · Journal of Plasma Physics
 [1];  [2];  [3];  [1]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Dartmouth College, Hanover, NH (United States)
  3. Univ. of Maryland, College Park, MD (United States)

Here, we present a novel discontinuous Galerkin algorithm for the solution of a class of Fokker–Planck collision operators. These operators arise in many fields of physics, and our particular application is for kinetic plasma simulations. In particular, we focus on an operator often known as the ‘Lenard–Bernstein’ or ‘Dougherty’ operator. Several novel algorithmic innovations, based on the concept of weak equality, are reported. These weak equalities are used to define weak operators that compute primitive moments, and are also used to determine a reconstruction procedure that allows an efficient and accurate discretization of the diffusion term. We show that when two integrations by parts are used to construct the discrete weak form, and finite velocity-space extents are accounted for, a scheme that conserves density, momentum and energy exactly is obtained. One novel feature is that the requirements of momentum and energy conservation lead to unique formulas to compute primitive moments. Careful definition of discretized moments also ensure that energy is conserved in the piecewise linear case, even though the kinetic-energy term, $v^2$ is not included in the basis set used in the discretization. A series of benchmark problems is presented and shows that the scheme conserves momentum and energy to machine precision. Empirical evidence also indicates that entropy is a non-decreasing function. The collision terms are combined with the Vlasov equation to study collisional Landau damping and plasma heating via magnetic pumping.

Research Organization:
Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Sponsoring Organization:
USDOE Office of Science (SC); US Air Force Office of Scientific Research (AFOSR); National Aeronautic and Space Administration (NASA); National Science Foundation (NSF)
Grant/Contract Number:
AC02-06CH11357; FG02-91ER54109; AC02-09CH11466; SC0010508; FC02-08ER54966
OSTI ID:
1668773
Journal Information:
Journal of Plasma Physics, Journal Name: Journal of Plasma Physics Journal Issue: 4 Vol. 86; ISSN 0022-3778
Publisher:
Cambridge University PressCopyright Statement
Country of Publication:
United States
Language:
English

References (31)

Progress with the COGENT Edge Kinetic Code: Collision Operator Options journal June 2012
The Mathematical Theory of Finite Element Methods book January 2008
The Serendipity Family of Finite Elements journal March 2011
FPPAC: A two-dimensional multispecies nonlinear Fokker-Planck package journal September 1981
Conservative global gyrokinetic toroidal full-f five-dimensional Vlasov simulation journal September 2008
Improved collision operator for plasma kinetic simulations with multi-species ions and electrons journal December 2015
A mass, momentum, and energy conserving, fully implicit, scalable algorithm for the multi-dimensional, multi-species Rosenbluth–Fokker–Planck equation journal September 2015
A fully non-linear multi-species Fokker–Planck–Landau collision operator for simulation of fusion plasma journal June 2016
Discontinuous Galerkin algorithms for fully kinetic plasmas journal January 2018
Collisional relaxation: Landau versus Dougherty operator journal October 2014
Gyrokinetic continuum simulation of turbulence in a straight open-field-line plasma journal May 2017
A drift-kinetic analytical model for scrape-off layer plasma dynamics at arbitrary collisionality journal November 2017
Effect of a weak ion collisionality on the dynamics of kinetic electrostatic shocks journal February 2019
Improved Bhatnagar-Gross-Krook model of electron-ion collisions journal January 1973
Heating of a Confined Plasma by Oscillating Electromagnetic Fields journal January 1958
Transition between Landau and Van Kampen Treatments of the Vlasov Equation journal January 1967
Eigenfunctions and eigenvalues of the Dougherty collision operator journal May 2007
Model Fokker-Planck Equation for a Plasma and Its Solution journal January 1964
Linearized model Fokker–Planck collision operators for gyrokinetic simulations. II. Numerical implementation and tests journal July 2009
Conservative discretization of the Landau collision integral journal March 2017
Full- f gyrokinetic simulation of turbulence in a helical open-field-line plasma journal January 2019
Gyrokinetic continuum simulations of plasma turbulence in the Texas Helimak journal April 2019
Theory of first‐order plasma heating by collisional magnetic pumping journal May 1989
Plasma Instabilities and Magnetic Field Growth in Clusters of Galaxies journal August 2005
Developments in the gyrofluid approach to Tokamak turbulence simulations journal August 1993
Implications of advanced collision operators for gyrokinetic simulation journal February 2017
Fokker-Planck Equation for an Inverse-Square Force journal July 1957
Plasma Oscillations with Diffusion in Velocity Space journal December 1958
The Local Discontinuous Galerkin Method for Time-Dependent Convection-Diffusion Systems journal December 1998
Plasma Physics for Astrophysics journal January 2005
Magnetic Pumping as a Source of Particle Heating and Power-law Distributions in the Solar Wind journal November 2017

Similar Records

Conservative discontinuous Galerkin scheme of a gyro-averaged Dougherty collision operator
Journal Article · Mon Aug 10 00:00:00 EDT 2020 · Nuclear Fusion · OSTI ID:1659475

Extension of Dougherty's model Fokker--Planck equation for a plasma
Journal Article · Fri Feb 01 00:00:00 EDT 1974 · J. Plasma Phys., v. 11, pp. 11-35 · OSTI ID:4334272

Dataset from: Improved multispecies Dougherty collisions
Dataset · Sat Mar 12 23:00:00 EST 2022 · OSTI ID:1897995