DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2013 EXPERIMENTAL CAMPAIGN Review | Direct submission with log-in | Request submission without log-in
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Title	251: New Study of Alfven Eigenmodes Induced Fast Ion Transport/Loss
Name:	Xi Chen chenxi@fusion.gat.com	Affiliation:	General Atomics
Research Area:	Energetic Particles	Presentation time:	Not requested
Co-Author(s):	the EP group	ITPA Joint Experiment :	No
Description:	To study the fast ion transport/loss induced by Alfven eignmodes by using our new prompt-loss "light-ion beam probe" which can measure the radial excursion of fast ion induced by individual mode.	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	Use plasma discharges similar to shot146096, with changes such as: - with constant 30L before 450ms (insert one 5ms 330L beam blip while 30L turned off to confirm it's "prompt" loss and couple 330L beam blips (30L off is not required) for diagnostic purpose) and then after 450ms, switch to constant 330L (insert one 5ms 30L beam blip while 330L turned off) - vary beam power to get a more controlled variation in mode amplitude - modify the current ramp (program a flat spot in current) to keep the prompt loss orbit close to FILD longer - puff gas to change the edge ionization gradient - swap constant 330R with constant 150R (to get BES measurement all the time)
Background:	Alfvén eigenmodes (AE) induced prompt loss of beam ions have been observed. The loss amplitude shows a linear relationship with the mode amplitude. The scale is different for different mode. By relating the AE induced prompt loss to the mode amplitude and the edge ionization rate(in practice, we use density scale length), the radial excursion of fast ion caused by individual mode can in inferred. It has been found that a single RSAE with amplitude of B_tw/|B| ~10E-3 can cause as large as 10cm radial kick. With better diagnostics setup, such as avoiding FILD PMT signal saturation, better ECEI optimal detection location, 150R for BES, we want to make a new study the AE induced fast ion transport/loss using this new prompt-loss "light-ion beam probe".
Resource Requirements:	normal BT and Ip direction, 30L, 150R, 330L
Diagnostic Requirements:
Analysis Requirements:
Other Requirements: