Spontaneous transition of core radial electric field driven by magnetic islands in the H-1NF heliac

This paper reports an experimental observation of spontaneous transition of the core radial electric field to a large positive value ( E r ∼ 5 kV m −1 ), with a strong electric-field shear (∼700 kV m −2 ) in a low temperature ( T e ∼ 10 eV) radio frequency generated argon plasma in the H-1NF heliac...

Full description

Saved in:
Bibliographic Details
Published in:Nuclear fusion 2011-08, Vol.51 (8), p.083003-6
Main Authors: Kumar, S.T.A, Blackwell, B.D, Howard, J, Harris, J.H
Format: Article
Language:English
Subjects:
Argon plasma
CONFIGURATION
CONFINEMENT BIFURCATIONS
Electric fields
Erbium
Excitation
GENERATION
INTERNAL TRANSPORT BARRIER
Magnetic islands
MODE
Oscillations
PLASMA
SHEAR
Spontaneous
STELLARATOR
TJ-II
TOKAMAK
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This paper reports an experimental observation of spontaneous transition of the core radial electric field to a large positive value ( E r ∼ 5 kV m −1 ), with a strong electric-field shear (∼700 kV m −2 ) in a low temperature ( T e ∼ 10 eV) radio frequency generated argon plasma in the H-1NF heliac stellarator. The transition, which seems to be driven by a spontaneous excitation of m = 2 magnetic islands near the core, is associated with a localized increase in the plasma density and excitation of coherent low frequency (∼3 kHz) oscillations possibly due to unstable E r shear driven modes. Evidence suggests development of the core electron-root scenario, which previously has been observed only at high temperature electron cyclotron heated plasmas.
ISSN:0029-5515
1741-4326
DOI:10.1088/0029-5515/51/8/083003