1. Species Effects on the H-mode Threshold and ELM Behavior in H(He3) and He4(H)
Plasmas in C-Mod
J A Snipes, P Lamalle
ITER Organization

2. What Power is Required to Reach High Confinement ?
The latest H-mode threshold power scaling for deuterium plasmas is:
The isotope dependence based on JET results in H, D, and D-T indicates that Pthresh  1/A for hydrogen isotopes
IF this scaling holds for ITER, H-mode will not be possible with Pin = 73 MW in hydrogen and hysteresis will be required to remain in H-mode in deuterium
To reach H98y2 ≥ 1, experiments indicate Pin > Pthresh is required ITER may depend on α power to sustain high confinement regimes
How does the H-mode threshold change in helium?
(Y. Martin, HMW 2008) 2

3. Can ELM Mitigation be Demonstrated in He in ITER?
ASDEX Upgrade has shown:
Pthresh(He) = Pthresh(D)
Latest threshold powers are lower than the recent scaling
More results in He would help extrapolate to ITER
Robust Type I ELMy H-mode in He in ITER would allow ELM mitigation techniques to be demonstrated before the active phases
This is very important for the ITER Research Plan

4. Species Effects on H-mode Threshold and ELM Behavior
Motivation: To have more information to extrapolate H-mode power threshold and ELM behavior in H and He plasmas to ITER so that the non-active phases of ITER operation can be planned accordingly.
Goals: 1) Determine how the H-mode threshold power scales in H and He. 2) Determine how the ELM behavior changes in H and He at low *.
Plan of execution: Scan ne from 11020 m-3 down to 41019 m-3 in He(H) ICRF plasmas and determine the H-mode power threshold vs ne. Operate at low * and determine the ELM behavior in He (Type I ?). Repeat these experiments in H(He3) ICRF plasmas to compare. The H plasmas could be planned during the last week of operation before the next planned opening of the machine to avoid difficulties returning to D(H) ICRF operation. 2 days requested.