Study of MHD activity in the HT-7 superconducting tokamak
An attempt is made to explain the behavior of the magneto-hydrodynamic (MHD) instabilities observed at values of the edge safety factor 3 < q ( a ) < 4 , on the HT-7 superconducting tokamak. For the poloidal-magnetic-field fluctuations observed at the Mirnov coils, Mirnov-coil analysis shows t...
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Published in | Physics letters. A Vol. 342; no. 1; pp. 175 - 180 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier B.V
04.07.2005
|
Subjects | |
Online Access | Get full text |
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Summary: | An attempt is made to explain the behavior of the magneto-hydrodynamic (MHD) instabilities observed at values of the edge safety factor
3
<
q
(
a
)
<
4
, on the HT-7 superconducting tokamak. For the poloidal-magnetic-field fluctuations observed at the Mirnov coils, Mirnov-coil analysis shows that the MHD activity consists predominantly of
m
=
2
mode. Estimates are given for the characteristic growth time of the
m
=
2
mode,
τ
g
, and the related rate of island growth,
d
W
/
d
t
. The experimental value of
τ
g
is found to be smaller than the linear theoretical one, and thus satisfy the condition
τ
A
<
τ
g
<
τ
S
(where ideal timescale is
τ
A
, and the resistive timescale is
τ
S
). However, the experimental and theoretical calculation of
d
W
/
d
t
are found to be in reasonable agreement with each other. |
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ISSN: | 0375-9601 1873-2429 |
DOI: | 10.1016/j.physleta.2005.05.032 |