Speaker
Dr
Brett Chapman
(USA)
Description
This overview of results from the MST reversed field pinch program summarizes physics important for the advancement of the RFP as well as for improved understanding of toroidal magnetic confinement in general. Topics include energetic particle effects, 3D helical equilibria, beta and density limit studies, microturbulence, ion heating, and magnetic self-organization physics. With neutral beam injection, several bursty energetic particle (EP) modes are observed. The profiles of the magnetic and density fluctuations associated with these EP-modes are measured using an FIR interferometer-polarimeter. Equilibrium reconstructions of the quasi-single-helicity 3D helical state are provided by the V3FIT code that now incorporates several of MST’s advanced diagnostics. A predator-prey theoretical model based on sheared flow and/or magnetic field has been developed that captures key QSH dynamics. Upgraded pellet injection permits study of density and beta limits over MST’s full range of operation, and an MST-record line-average density of 0.9E20 / m^3 (n/n_G =1.4) has been obtained. Plasma beta exhibits saturation at beta_tot ≤ 20% for a wide range of density, 0.2 < n/n_G < 1.6. Gyrokinetic simulations (GENE) based on experimental toroidal equilibrium reconstructions predict unstable trapped electron modes. Nonlinear simulations show that the “Dimits shift” is large and persists at finite beta. Experimentally, small-scale density fluctuations are detected in improved confinement plasmas. Impurity ion temperature measurements reveal a charge-to-mass-ratio dependence in the rapid heating that occurs during a sawtooth crash. Also, a toroidal asymmetry in the ion temperature is measured, correlated with 3D magnetic structure associated with tearing modes. Magnetic self-organization studies include measurements and modeling of the dynamo emf in standard RFP operation as well as with an applied ac inductive electric field to investigate the dynamics of oscillating field current drive (OFCD). Extended MHD computation for standard RFP conditions using NIMROD predicts dynamical coupling of current and plasma flow relaxation. The dynamo emf has also been measured when OFCD is applied, strengthening the understanding of and possibility for steady-state current sustainment using inductive current drive.
| Country or International Organisation | USA |
|---|---|
| Paper Number | OV/5-3 |
Primary author
Mr
John Sarff
(USA)
Co-authors
Dr
Abdulgader Almagri
(University of Wisconsin-Madison)
Mr
Adam Falkowski
(University of Wisconsin-Madison)
Dr
Alexander Ivanov
(Budker Institute of Nuclear Physics)
Mr
Andrew Seltzman
(University of Wisconsin-Madison)
Dr
Barbara Momo
(Consorzio RFX)
Prof.
Boris Breizman
(The University of Texas at Austin)
Dr
Brett Chapman
(USA)
Prof.
Carl Sovinec
(University of Wisconsin-Madison)
Prof.
Cary Forest
(University of Wisconsin-Madison)
Mr
Daniel Carmody
(University of Wisconsin-Madison)
Dr
Daniel Den Hartog
(University of Wisconsin-Madison)
Prof.
Darren Craig
(Wheaton College)
Dr
David Brower
(University of California-Los Angeles)
Dr
David Terranova
(Consorzio RFX)
Dr
Deyong Liu
(University of California-Irvine)
Dr
Dianne Demers
(XanthoTechnologies, LLC)
Dr
Donald Holly
(University of Wisconsin-Madison)
Dr
Donald Spong
(Oak Ridge National Laboratory)
Mr
Eli Parke
(University of Wisconsin-Madison)
Dr
Emilio Martines
(Consorzio RFX)
Dr
Fulvio Auriemma
(Consorzio RFX)
Mr
Garth Whelan
(University of Wisconsin-Madison)
Prof.
Hillary Stephens
(Pierce College)
Mr
James Duff
(University of Wisconsin-Madison)
Dr
James Titus
(Florida A&M University)
Dr
Jay Anderson
(University of Wisconsin)
Dr
Jeff Waksman
(University of Wisconsin-Madison)
Mr
John David Lee
(University of Wisconsin-Madison)
Dr
John Goetz
(University of Wisconsin-Madison)
Dr
Jon Koliner
(University of Wisconsin-Madison)
Mr
Joseph Trianna
(University of Wisconsin-Madison)
Dr
Joshua Reusch
(University of Wisconsin-Madison)
Mr
Joshua Sauppe
(University of Wisconsin-Madison)
Dr
Karsten McCollam
(University of Wisconsin-Madison)
Mr
Kyle Caspary
(University of Wisconsin-Madison)
Dr
Liang Lin
(University of California Los Angeles)
Dr
Linjin Zheng
(University of Texas-Austin)
Mr
Lucas Morton
(University of Wisconsin-Madison)
Mr
M Li
(University of Texas-Austin)
Dr
Maria Ester Puiatti
(Consorzio RFX)
Dr
Mark Nornberg
(University of Wisconsin-Madison)
Mr
Mark Thomas
(University of Wisconsin-Madison)
Dr
Matthew Galante
(University of Wisconsin-Madison)
Dr
Meghan McGarry
(University of Wisconsin-Madison)
Mr
Michael Borchardt
(University of Wisconsin-Madison)
Dr
Monica Spolaore
(Consorzio RFX)
Dr
Moritz Pueshel
(University of Wisconsin-Madison)
Dr
N Stupishin
(Budker Institute of Nuclear Physics)
Dr
Paolo Franz
(Consorzio RFX)
Dr
Paolo Innocente
(Consorzio RFX)
Dr
Paolo Piovesan
(Consorzio RFX)
Dr
Paolo Zanca
(Consorzio RFX)
Mr
Paul Nonn
(University of Wisconsin-Madison)
Prof.
Paul Terry
(University of Wisconsin-Madison)
Dr
Peter Fimognari
(XanthoTechnologies, LLC)
Dr
Pieter Deichuli
(Budker Institute of Nuclear Physics)
Dr
R.W. (Bob) Harvey
(CompX)
Dr
Rita Lorenzini
(Consorzio RFX)
Dr
S Polosatkin
(Budker Institute of Nuclear Physics)
Dr
Santosh Kumar
(University of Wisconsin-Madison)
Mr
Scott Eilerman
(University of Wisconsin-Madison)
Dr
Stephano Munaretto
(University of Wisconsin-Madison)
Mr
Steve Oliva
(University of Wisconsin-Madison)
Dr
Susanna cappello
(Consorzio RFX)
Dr
Vladimir Davydenko
(Budker Institute of Nuclear Physics)
Dr
Vladimir Mirnov
(University of Wisconsin-Madison)
Dr
Weixing Ding
(UCLA)
Mr
William Cappechi
(University of Wisconsin-Madison)
