April 4-6

Abstract Details

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Author: Alexandre P Sainterme
Requested Type: Poster
Submitted: 2022-03-04 10:29:24

Co-authors: C.R. Sovinec

Contact Info:
University of Wisconsin-Madison
1500 Engineering Drive
Madison, WI   53706

Abstract Text:
A reduced fluid model for runaway electrons is incorporated in the time advance of the NIMROD code. Runaway electrons are treated as a distinct fluid species that flows with a velocity consisting of a large prescribed parallel component and a perpendicular component given by the E cross B drift. There is a volumetric source density for the runaway species given by the local background density and parallel electric field via the Dreicer mechanism [Connor and Hastie, NF 15, 415(1975)]. and a volumetric source density representing the avalanche runaway generation [Rosenbluth and Putvinski, NF 37, 1355(1997)]. The runaway density evolution couples to the MHD equations via Ohm's law in accordance with the assumption that the runaway species does not contribute to the resistive electric field, like the JOREK model presented in Bandaru, et al. [Bandaru, et al., PRE 99, 063317(2019)], and M3D-C1 model in Liu, et al. [Liu et al., PPCF 63, 125031(2021)]. Results of an artificial thermal quench test case show good agreement between the NIMROD and JOREK calculations for the conversion of thermal current to runaway current. Recent nonlinear calculations applying the model to a DIII-D-like equilibrium show initiation of a runaway beam on the high-field side following the dissipation of thermal energy that progresses to a hollow runaway density profile.
Work supported by US DOE grant DE-SC0018001