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Title	215: The n=3 RFA excitation in the ELM-induced RWM by applying the n=3 extra error field
Name:	Michio Okabayashi ()	Affiliation:	Princeton Plasma Physics Laboratory
Research Area:	RWM Physics	Presentation time:	Not requested
Co-Author(s):	A. Garofalo, Yongkyoon In, G. Jackson, R. LaHaye, H. Reimerdes, Ted Strait, H. Takahashi
Description:	In the RWM buildup period, we often observe the ELM-induced RWM followed by the RFA period before the final collapse takes place. Since the ELM event produces many n-components, it is quite possible that the n=3RFA also should be excited along with the n=1 component in the event of the ELM-induced RWM events. Before 2005, we observed frequently the excitation of n=3 components along with n=1 component in ELM-induced RWMs. However, strangely in 2006-2007 campaign, we seldom observed the n=3 component until very late period of the discharge termination. At present, this weak n=3 component remains as a little mystery. Here, it is hypothesized that the n=3 error field component was indeed reduced by the coil lead correction in 2005 major opening period. If this hypothesis is reasonable, the n=3 RFA should reoccur in the ELM-induced RWM by applying n=3 error field. If the n=3 RFA reappears, we will attempt to excite the n=2 RFA by applying n=2 field from C-coils.
Experimental Approach/Plan:	Experiment (1) We introduce the n=3 component from I- or C- coil and then we observe the ELM event (2) The DEFC of n=1 should be kept applied to minimize the n=1 component for better noise ratio. (3) if n=3 RFA is observed in ELM-induced RFA, n=2 RFA possibility will be explored
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