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	294: Simulated Alpha particle dillution
Name:	Gary Staebler staebler@fusion.gat.com	Affiliation:	General Atomics
Research Area:	Turbulence & Transport	Presentation time:	Not requested
Co-Author(s):		ITPA Joint Experiment :	No
Description:	Use Helium NBI in a low density ITER Baseline H-mode target to simulate the impact of alpha particles on the energy transport in a burning plasma. The fast helium ion density would be varied to see how the fast helium ion dillution impacts the thermal transport.	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	Start with the DIII-D similarity discharge for the ITER baseline H-mode in Deuterium. Add Helium NBI to produce a population of Helium fast ions. Balanced injection is preferable to take out the rotation impact on confinement. Compare with discharges heated with central ECH to the same power. Compare with discharges heated with deuterium NBI to the same power from previous experiments.
Background:	The impact of helium dillution on fusion power is usually computed by assuming the electron density and ion temperatures are unchanged as the helium added so that just the dillution of the fuel is used. This overestimates the impact of heluim dilution since the fast alpha particles will be stabilizing the the ITG modes. Hence increasing the alpha density will both increase the ion temperature and dilute the fuel. The increse in ion temperature compensates somewhat for the reduced fuel density so the fusion power does not go down as much as the fixed temperature model would predict. This experiment aims to determine how much the ion temperature increases.
Resource Requirements:	ITER baseline H-mode resources + two beam boxes in Helium co+cnt.
Diagnostic Requirements:	full plasma profile and fast particle diagnostics
Analysis Requirements:	ONETWO or TRANSP analysis. TGLF transport predictions with XPTOR or TGYRO, GYRO simulations of selected cases.
Other Requirements: