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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...
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Published in: | Nuclear fusion 2011-08, Vol.51 (8), p.083003-6 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites |
Online Access: | Get full text |
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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. |
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ISSN: | 0029-5515 1741-4326 |
DOI: | 10.1088/0029-5515/51/8/083003 |