April 15-17

Abstract Details

files Add files

status:file name:submitted:by:
approvedfrancisquezsherwood_2009.pdf2019-04-18 09:03:39Manaure Francisquez

Abstracts

Author: Manaure Francisquez
Requested Type: Poster
Submitted: 2019-04-06 01:23:38

Co-authors: J. Juno, A.Hakim, T. Bernard, N. Mandell, G. W. Hammett

Contact Info:
MIT Plasma Science and Fusion Center
77 Massachusetts Av, NW16
Cambridge, MA   02139
USAA

Abstract Text:
A discontinuous Galerkin (DG) formulation of a model nonlinear Fokker-Planck-type collision operator, known as the Dougherty operator, is shown to satisfy conservation laws exactly in the discrete sense [1]. Conservation is independent of numerical resolution. This DG approach to Fokker-Planck-type collisions is built on weak equalities to recover continuous functions from a DG solution, and to compute bulk velocities and temperatures. Together with corrections from truncated velocity space, weak equivalence leads to unique prescriptions for obtaining parallel velocities and thermal speeds. These techniques are incorporated in a multi-species version of the Dougherty operator which reproduces the correct Maxwellian energy and momentum exchange rates. This model of multi-species collisions avoids the possibility of negative temperatures found in equivalent BGK operators [2], but it has not yet been shown to have and H-theorem. We discuss the challenges leading up to these limitations and present some benchmark problems for both self- and multi-species collisions with the Gkeyll code.

[1] A. Hakim, M. Francisquez, J. Juno, G. W. Hammett, arXiv:1903.08062 (2019)

[2] J. Greene, Phys. of Fluids 16, 11 (1973).

Comments: