Speaker
Dr
Yuki Takemura
(National Institute for Fusion Science)
Description
The frequency slowing-down mechanism of the locked-mode-like instability without a large
magnetic island is investigated for the first time, based on the LHD experimental analysis.
The slowing-down frequency is caused by two processes. One is the resonant surface moving
to the small E × B rotation frequency region and the other is the slowing-down E × B rotation
frequency around the resonant surface. Both processes are almost the same as those of the
instability with a large
magnetic island. The new
exprerimental results
presented in this synopsis
suggest that the mode
frequency slows down
even though the precursor
does not have a large
magnetic island. In
addition, the duration of
the frequency
slowing-down phase
becomes longer as the
external RMP amplitude
becomes smaller. This is
because the slowing-down
rate of the E × B rotation
frequency around the
resonant surface after
excitation of the precursor
is smaller for a smaller
external RMP amplitude.
These results also suggest
that error fields, which
have the same effect as the
RMP, should be reduced
to obtain sufficient time
for controlling the
locked-mode-like
instability.
| Country or International Organization | Japan |
|---|---|
| Paper Number | EX/P3-16 |
Primary author
Dr
Yuki Takemura
(National Institute for Fusion Science)
Co-authors
Dr
Hayato Tsuchiya
(National Institute for Fusion Science)
Dr
Ichihiro Yamada
(National Institute for Fusion Science)
Dr
Katsumi Ida
(National Institute for Fusion Science)
Dr
Kiyomasa WATANABE
(National Institute for Fusion Science)
Dr
Mikirou Yoshinuma
(National Institute for Fusion Science)
Prof.
Satoru Sakakibara
(National Institute for Fusion Science)
Dr
Tokihiko Tokuzawa
(National Institute for Fusion Science)
Dr
Yoshiro NARUSHIMA
(National Institute for Fusion Science)
