DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2013 EXPERIMENTAL CAMPAIGN Review | Direct submission with log-in | Request submission without log-in
Print this page

Print this page
Title	235: High resolution Te pedestal measurements in RMP ELM suppression experiments
Name:	Dinh Truong truongd@fusion.gat.com	Affiliation:	Sandia National Lab
Research Area:	ELM Control	Presentation time:	Not requested
Co-Author(s):	Max Austin, George McKee, ELM control aficionados	ITPA Joint Experiment :	No
Description:	The goal of the experiment is to measure the changes in the pedestal Te as RMP ELM suppression is applied using the new high-spatial-resolution (HR) ECE channels. The pedestal Te profile as well as the pedestal Te oscillations will be measured with microsecond time resolution using optically thick electron cyclotron emission. In addition, edge BES measurements will supply high resolution information about the density fluctuation changes on the same fast time scale. Significant increase in density fluctuations are observed with BES in the pedestal and interior region during RMP ELM-suppressed discharges. These measurements may help elucidate the q-dependence/resonance condition of the ELM suppression.	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	The experiment can be carried out in any RMP ELM suppression set of discharges with Bt in the range 1.9-2.1 T. The goal will be to examine fast (fluctuation scale) and slow (equilibrium) changes in the edge temperature profile as the ELM-suppression resonance condition is entered and exited.
Background:	Up until now it was not possible to measure the edge Te profile with high resolution due to the limitations of the fixed frequency ECE radiometer channels. In 2013 eight new ECE channels with narrow radial separation and variable location capability will be added to the midplane ECE radiometer diagnostic. The channels will cover nominally 4 cm of radius with 5 mm resolution, with the actual resolution limited somewhat by relativistic broadening. Previous measurements of Te near the edge could only give a general trend of the Te gradient. With the HR channels it will be possible, for example, to observe the phase relationship of oscillations at various radii near the resonant q surface.
Resource Requirements:
Diagnostic Requirements:	ECE, BES
Analysis Requirements:
Other Requirements: