Consideration of ECH Modifications andImplication to ITER Steady State Scenarios
M. Murakami and J.M. Park
ITPA-IOS meeting
Kyoto, Japan
October 20 , 2011

BACKGROUND / OUTLINE•! The last presentation (IOS TG at JET) on possible Upgrade ofthe Upper Launcher and its effects on SS scenarios•! Japanese ECH Team looking into Equatorial Launcher
modifications allowing its poloidal steering– Increase and broadened CD efficiency•! Comparison between Effects of the Upper Launcher andEquatorial Launcher on steady state scenarios•! Steady State Exploration – benefit to the 9-MA scenarios-! CD comparison with 9-MA case-! Optimization of the 9-MA scenario with ECH upgrade forsimultaneous achievement of fNI=100% and Q=5-! USM + ELT upgrades3!
-! doubling the ECH power (40MW)The ITER Day-1 H & CD Systems Had Some Gap In CD Coverage
For Steady State Scenario Development•! CD efficiency (kA/MW) for the ITER
main H&CD sources for a fixedprofiles (8-MA Baseline)•! The present H&CD capability shows a
gap of CD at ! ! 0.4•! The upper launchers (and EQL) are
optimized for NTM feedback control! Narrow!! Hopefully sufficient with LSMalone•!

For current profile control needs–!

Broader CD profile preferred
•!

4!

–!

Even possible for D; controlof NTM

High efficiency

CD Profiles Calculated increase broadening and integrated
CD as alpha increases from 30 to 40 degrees•! The ECH/CD calculation
using CQL3D/TORAY totake into account theelectron momentum
conservation•! For current profile control
needs broadening•! Doppler effects in EQL aresmaller than in USM, there
is no big shoulder in H andCD profiles•! See R. Prater’s presentation

Poloidal Angle Scams In EQL Launcher (A = -26 To 40 Degree)
Covers Wide Radial Range (R = 0 To 0.7)
ELM30mn scan:!
B = 30!
A = +24 -> -40!
ELM35mn scan!
B=35!
A= 24 -> -40 !

6!

10/20/11!

Increase beta
decreases radial
ranges but broadenscurrent profiles!

Combination of ELT and USM modifications should be able tocover the H&CD control capability in rho = 0 to 0.9!! See R. Prater’s Culhampresentation•! This ECH/CD calculation
using CQL3D/TORAY to take
into account the electron
momentum conservation•! The (linear) decreases ofCD efficiency in radius isdue to increases in electron
trapped particle fraction
7!

•! Opposite to the NBCDcase

ECCD upgrades increases very substantially ITER H&CD capability
in the entire range of the plasma radius!
•! The Use of ECCD should not belimited to NTM control!!

The previous UL design wasoptimized only for NTM feedback
which requires narrow CD•!

•!

8!

Hopefully LSM18 system issufficient for it

Current profile control for SS
operation needs

OPTIMIZATION OF 9-MA SS SCENARIOS•! NBI geometry : part of off-axis moved towardthe axis•! Minimize ICRF power (except the seed currentneeded)•! ECH Upgrades:
1.! Upper launcher to broaden off-axis peaking
using USM26
2.! Consider < 40-MW ECH system•! Try to get simultaneous achievement of 100% fNI
and Q=59!

Optimization of 9-MA SS scenarios using the ECCD upgrades
approaches close to the goal of Q=5 and fNI=100%
NBI:
16.5MW on-axis+ 16,5MW off-axis
No ICRF)ECCD-40MW (upgrade)
Q=5.35
PDT = 391MW
fNI = 98%
fBS = 63%
fNB = 21%
fEC = 14%
H98 = 1.44
NGW = 0.90100"!Broad shear by spreading on+off NBI overlapping with ECCD:–– ELT30-6 (20 MW) + USM26-7 (20 MW)

CONCLUSION• Modifications of upper and Top EQ ECH launchers for current profilecontrol was considered. Increase poloidal and toroidal angles leads
to :-- increasing CD by ~50% (calculated with CQL3D/TORAY)-- filling in the previous gap between on axial CD (EQ Launchersand off-axis NBI) and the Upper launchers• 9-MA SS scenarios with the ECH upgrade was examined using GLF23with ITER-Demo edge conditions. Further exploration was in progress:- The ECH upgrades- Increase ECH power to 40MW (still keeping total external powerof 73MW)- use off-axis NBI and on-axis NBI (with varying steering angles)- minimize ICRF power (except seed current needed)• These explorations obtained full NI and QDT>5.6 with smooth reverse
sheer q(!) profile (q-min>15)