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Title: Improved confinement region without large magnetohydrodynamic activity in TPE-RX reversed-field pinch plasma

We found that spontaneous improved confinement was brought about depending on the operating region in the Toroidal Pinch Experiment-Reversed eXperiment (TPE-RX) reversed-field pinch plasma [Y. Yagi et al., Fusion Eng. Des. 45, 421 (1999)]. Gradual decay of the toroidal magnetic field at plasma surface B{sub tw} reversal makes it possible to realize a prolonged discharge, and the poloidal beta value and energy confinement time increase in the latter half of the discharge, where reversal and pinch parameters become shallow and low, respectively. In the latter half of the discharge, the plasma current and volume-averaged toroidal magnetic field 〈B{sub t}〉 increase again, the electron density slowly decays, the electron temperature and soft X-ray radiation intensity increase, and the magnetic fluctuations are markedly reduced. In this period of improved confinement, the value of (〈B{sub t}〉-B{sub tw})/B{sub pw}, where B{sub pw} is the poloidal magnetic field at the plasma surface, stays almost constant, which indicates that the dynamo action occurs without large magnetohydrodynamic activities.
Authors:
; ; ;  [1]
  1. Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568 (Japan)
Publication Date:
OSTI Identifier:
22403309
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ELECTRON DENSITY; ELECTRON TEMPERATURE; MAGNETIC FIELDS; PLASMA; REVERSE-FIELD PINCH; SOFT X RADIATION; SURFACES; TPE-RX DEVICE