Title: Two-temperature effects in Hall-MHD simulations of the HIT-SI experiment

Abstract

A two-temperature Hall-magnetohydrodynamic (Hall-MHD) model, which evolves the electron and ion temperatures separately, is implemented in the PSI-Tet 3D MHD code and used to model plasma dynamics in the Helicity Injected Torus–Steady Inductive (HIT-SI) experiment. The two-temperature model is utilized for HIT-SI simulations in both the PSI-Tet and NIMROD codes at a number of different injector frequencies in the 14.5–68.5 kHz range. At all frequencies, the NIMROD two-temperature model results in increased toroidal current, lower chord-averaged density, higher average temperatures, outward radial shift of the current centroid, and axial symmetrization of the current centroid, relative to the single-temperature NIMROD simulations. The two-temperature PSI-Tet model illustrates similar trends, but at high frequency operation, it exhibits lower electron temperature, smaller toroidal current, and decreased axial symmetrization with respect to the single-temperature PSI-Tet model. With all models, average temperatures and toroidal currents increase with the injector frequency. Power balance and heat fluxes to the wall are calculated for the two-temperature PSI-Tet model and illustrate considerable viscous and compressive heating, particularly at high injector frequency. Parameter scans are also presented for artificial diffusivity, wall temperature, and density. Both artificial diffusivity and the density boundary condition significantly modify the plasma density profiles, leading to largermore » average temperatures, toroidal current, and relative density fluctuations at low densities. As a result, a low density simulation achieves sufficiently high current gain (G > 5) to generate significant volumes of closed flux lasting 1–2 injector periods.« less

Authors:

Kaptanoglu, Alan A.  ^[1];

• Search DOE PAGES for author "Kaptanoglu, Alan A."
• Search DOE PAGES for ORCID "0000-0002-6337-2907"

Benedett, Tom E.  ^[1];

• Search DOE PAGES for author "Benedett, Tom E."
• Search DOE PAGES for ORCID "0000-0001-9888-5545"

Morgan, Kyle D.  ^[1];

• Search DOE PAGES for author "Morgan, Kyle D."
• Search DOE PAGES for ORCID "0000-0002-1382-4012"

Hansen, Chris J.  ^[2];

• Search DOE PAGES for author "Hansen, Chris J."
• Search DOE PAGES for ORCID "0000-0001-6928-5815"

Jarboe, Thomas R.  ^[1]

• Search DOE PAGES for author "Jarboe, Thomas R."
• Search DOE PAGES for ORCID "0000-0001-7840-5524"

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+ Show Author Affiliations

1. Univ. of Washington, Seattle, WA (United States)
2. Univ. of Washington, Seattle, WA (United States); Columbia Univ., New York, NY (United States)

Publication Date:

Tue Jul 14 00:00:00 EDT 2020

Research Org.:

Univ. of Washington, Seattle, WA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Fusion Energy Sciences (FES)

OSTI Identifier:

1638351

Alternate Identifier(s):

OSTI ID: 1638410

Grant/Contract Number:  

FG02-96ER54361; SC0016256; AC02–05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Physics of Plasmas

Additional Journal Information:

Journal Volume: 27; Journal Issue: 7; Journal ID: ISSN 1070-664X

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma dynamics; numerical methods; magnetohydrodynamics; plasma confinement; computer simulation; dynamical systems; self-organization; MHD; spheromak