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	124: Electron Energy Transport during q0 control using modulated EC power
Name:	Philip Ryan ryanpm@ornl.gov	Affiliation:	Oak Ridge National Lab
Research Area:	Inductive Scenarios	Presentation time:	Not requested
Co-Author(s):	S. Diem, M. Murakami, J.M. Park, J.C. Hosea, R.J. Perkins, G. Taylor	ITPA Joint Experiment :	No
Description:	This experiment will modulate the ECH power to study the heating deposition and electron transport in ITER relevant discharges on DIII-D. EC modulation at both low frequency (~5 Hz, to study the CD efficiency and q0 evolution) and high frequency (~30 Hz, to study heating efficiency and deposition profile) will be employed with break-in-slope and Fourier transform analyses. These frequencies were chosen to avoid characteristic ELM and sawtooth frequencies (7-10 Hz).	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	All discharges should be run with no beta feedback on NBI power so that the NBI power remains constant. Run plan: 1. Begin with ITER baseline scenario discharge 150828. Restriction on outer gap is not required as FW will not be used, although we will start with the same gap to maintain similar confinement times. Density should be lower than the baseline discharge so that 2nd harmonic ECE is not cut off. The beams should be balanced to minimize the applied torque. 2. Apply modulated radial launch EC heating at a rate of 5 Hz. 3. Apply modulated radial launch EC heating at a rate of 30 Hz. 4. Increase density to that of original discharge 150828 then repeat the modulated radial launch EC heating at rates of 5 Hz and 30 Hz. This will require 3rd harmonic ECE monitoring of Te. 5. Reduce counter and increase co-current NBI to increase torque/plasma rotation and run modulated EC heating at 5 Hz and 30 Hz for low density conditions of [1]. 6. Repeat 5 with high density conditions of [4]. 7. Choose the conditions of [1]-[6] that demonstrate the best heating and increases in stored energy. Replace the radial ECH injection with equivalent amount of tangentially injected counter-ECCD and repeat modulation experiments to evaluate the change in q0.
Background:	he direct electron heating comparison made between FW and ECW in 2012 showed that both techniques had difficulty in consistently and efficiently heating the core plasma for the ITER Baseline Scenario. Understanding the EC power deposition and electron heat transport is important both to evaluate a proposed ITER operation scenario that uses net counter- ECCD to control q0, and to improve our ongoing analysis of FW heating of IBS plasmas.
Resource Requirements:	Machine time: 1 day of machine time Number of gyrotrons: 6 Number of neutral beam sources: 2, plus beam blips for MSE
Diagnostic Requirements:	ECE, 3HECE, CHERS, MSE, UCLA reflectometor, ORNL reflectometor
Analysis Requirements:	TRANSP, CURRAY
Other Requirements: