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

Effects of temperature and density evolution in MHD simulations of HIT-SI

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.5142298· OSTI ID:1608226
 [1];  [2];  [2];  [2]
  1. Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195, USA; University of Washington
  2. Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195, USA
The helicity injected torus-steady inductive (HIT-SI) experiment uses steady inductive helicity injection to form a spheromak equilibrium and sustain the structure against resistive decay. Helicity injection is performed using two half-tori “injectors” connected to the main plasma volume, whose fields are oscillated in an AC manner. The properties of the sustained spheromak equilibrium have been experimentally observed to vary with the frequency of the injector oscillation, producing higher current gains and more-symmetric and outwardly shifted current centroids with higher frequency. A computational scan of injector frequency using the 3D MHD code PSI-Tet, which models the entire HIT-SI plasma volume including the injectors, has been performed, including a comparison of the results using the full Hall MHD model to those obtained using a simplified “zero-beta” (constant temperature and density) model. The results of both PSI-Tet models are also compared with experimental data and with simulations using the NIMROD code, which does not model the injector regions. The results of the PSI-Tet simulations show that the average temperature and current gain increase with injector frequency, in agreement with experimental trends. The simulations also show qualitative changes in the dynamics of several quantities with increasing injector frequency, such as density oscillations and current evolution. However, the outward shift and symmetrizing of the current centroid, observed experimentally, are not observed in these MHD simulations, indicating that unresolved or excluded dynamics may be important.
Research Organization:
Univ. of Washington, Seattle, WA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Grant/Contract Number:
FG02-96ER54361; SC0016256
OSTI ID:
1608226
Alternate ID(s):
OSTI ID: 1608171
Journal Information:
Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 4 Vol. 27; ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English

References (36)

The dynomak: An advanced spheromak reactor concept with imposed-dynamo current drive and next-generation nuclear power technologies journal April 2014
Nonlinear magnetohydrodynamics simulation using high-order finite elements journal March 2004
A hierarchy of low-dimensional models for the transient and post-transient cylinder wake journal December 2003
The three-dimensional magnetohydrodynamics of ac helicity injection in the reversed field pinch journal April 2003
Three-dimensional magnetohydrodynamic simulations of the Helicity Injected Torus with Steady Inductive drive journal May 2005
Computational modeling of fully ionized magnetized plasmas using the fluid approximation journal May 2006
Energy confinement and magnetic field generation in the SSPX spheromak journal May 2008
NIMROD resistive magnetohydrodynamic simulations of spheromak physics journal March 2008
Equilibrium evolution in oscillating-field current-drive experiments journal August 2010
Diamagnetic thresholds for sawtooth cycling in tokamak plasmas journal October 2011
Simulation of current-filament dynamics and relaxation in the Pegasus Spherical Tokamak journal August 2012
Relaxation-time measurement via a time-dependent helicity balance model journal January 2013
Validation of single-fluid and two-fluid magnetohydrodynamic models of the helicity injected torus spheromak experiment with the NIMROD code journal August 2013
Sustained spheromaks with ideal n  = 1 kink stability and pressure confinement journal August 2014
Simulation of injector dynamics during steady inductive helicity injection current drive in the HIT-SI experiment journal April 2015
Numerical studies and metric development for validation of magnetohydrodynamic models on the HIT-SI experimenta) journal May 2015
Validation of extended magnetohydrodynamic simulations of the HIT-SI3 experiment using the NIMROD code journal December 2017
Hall effect on tearing mode instabilities in tokamak journal October 2017
Simulation of multi-pulse coaxial helicity injection in the Sustained Spheromak Physics Experiment journal March 2018
Ion heating and magnetohydrodynamic dynamo fluctuations in the reversed‐field pinch journal December 1992
The biorthogonal decomposition as a tool for investigating fluctuations in plasmas journal October 1994
MHD stability of Spheromak journal April 1979
MHD equilibria in a spheromak sustained by coaxial helicity injection journal July 1999
Recent results from the HIT-SI experiment journal May 2011
Imposed-dynamo current drive journal July 2012
Multimode observations and 3D magnetic control of the boundary of a tokamak plasma journal June 2013
Multichannel fluctuation data analysis by the singular value decomposition method. Application to MHD modes in JET journal September 1992
Review of spheromak research journal June 1994
Development of validation metrics using biorthogonal decomposition for the comparison of magnetic field measurements journal March 2015
Plasma response to sustainment with imposed-dynamo current drive in HIT-SI and HIT-SI3 journal May 2017
Evidence for Separatrix Formation and Sustainment with Steady Inductive Helicity Injection journal October 2011
Relaxation of Toroidal Plasma and Generation of Reverse Magnetic Fields journal November 1974
Spheromak Formation by Steady Inductive Helicity Injection journal September 2006
Relaxation and magnetic reconnection in plasmas journal July 1986
A Proof of Principle of Imposed Dynamo Current Drive: Demonstration of Sufficient Confinement journal November 2014
Steady Inductive Helicity Injection and Its Application to a High-Beta Spheromak journal July 1999

Similar Records

Two-temperature effects in Hall-MHD simulations of the HIT-SI experiment
Journal Article · Mon Jul 13 20:00:00 EDT 2020 · Physics of Plasmas · OSTI ID:1638351

Simulation of injector dynamics during steady inductive helicity injection current drive in the HIT-SI experiment
Journal Article · Wed Apr 15 00:00:00 EDT 2015 · Physics of Plasmas · OSTI ID:22408314

Simulation of injector dynamics during steady inductive helicity injection current drive in the HIT-SI experiment
Journal Article · Thu Apr 09 20:00:00 EDT 2015 · Physics of Plasmas · OSTI ID:1608230