Bell / IFS / 070306 1

Physics Results from the National Spherical Torus Experiment

M.G. Bell for the NSTX Group

Princeton Plasma Physics Laboratory

Princeton University, Princeton, NJ

Supported byOffice ofScience

Culham Sci Ctr

U St. Andrews

York U

Chubu U

Fukui U

Hiroshima U

Hyogo U

Kyoto U

Kyushu U

Kyushu Tokai U

NIFS

Niigata U

U Tokyo

JAERI

Ioffe Inst

RRC Kurchatov Inst

TRINITI

KBSI

KAIST

ENEA, Frascati

CEA, Cadarache

IPP, Jülich

IPP, Garching

ASCR, Czech Rep

U Quebec

College W&MColumbia UComp-XGeneral AtomicsINELJohns Hopkins ULANLLLNLLodestarMITNova PhotonicsNew York UOld Dominion UORNLPSIPrinceton USNLThink Tank, Inc.UC DavisUC IrvineUC Los AngelesUC San DiegoU ColoradoU MarylandU RochesterU WashingtonU Wisconsin

Bell / IFS / 070306 2

“Spherical Torus” Extends Tokamak to Extreme Toroidicity

•Motivated by potential for increased [Peng & Strickler, 1980s]

max (= 20p/BT2) = C·Ip/aBT C·Aq

BT: toroidal magnetic field on axis;p: average plasma pressure;Ip: plasma current; a: minor radius;

: elongation of cross-section;A: aspect ratio (= R/a); q: MHD “safety factor” (> 2)C: Constant ~3%·m·T/MA

[Troyon, Sykes - early 1980s]

•Confirmed by experiments–max ≈ 40%

[START (UK) 1990s]

Spherical TorusA ≈ 1.3, qa = 12

ConventionalTokamak

A ≈ 3, qa = 4

Fieldlines

Bell / IFS / 070306 3

NSTX Designed to Study High-Temperature Toroidal Plasmas at Low Aspect-Ratio

Aspect ratio A 1.27

Elongation 2.5 (3.0)

Triangularity 0.8

Major radius R0 0.85m

Plasma Current Ip 1.5MA

Toroidal Field BT0 0.6

(0.55) T

Pulse Length 1.5s

Auxiliary heating:

NBI (100kV) 7 MW

RF (30MHz) 6 MW

Central temperature 1 – 3 keV

Slim center column

with TF, OH coils

Conducting platesfor MHD stability

Bell / IFS / 070306 4

NSTX Research Contributes to Fusion Energy Development, ITER Physics and Plasma

Science

•Determine the physics principles of ST confinement

– Limits, scaling, control, heating schemes, integration

•Complement and extend conventional aspect-ratio tokamaks

– Utilize low aspect ratio and high-T to address basic physics of toroidal confinement

•Support preparation for burning plasma research in ITER

– Participate in the ITPA and USBPO

•Complement ITER by exploring possibilities for an attractive Component Test Facility and Demonstration Power Plant

Bell / IFS / 070306 5

In Addition to High , New Physics Regimes Are Expected at Low Aspect Ratio

•Intrinsic cross-section shaping ( > 2, BP/BT ~ 1)

•Large fraction of trapped particles √r/R))

•Large gyro-radius (a/i ~ 30–50)

•Large bootstrap current (>50% of total)

•Large plasma flow & flow shear (M ~ 0.5)

•Supra-Alfvénic fast ions (vNBI/vAlfvén ~ 4)

•High dielectric constant ( ~ 30–100)

Bell / IFS / 070306 6

Key ST Physics Issues to Explore in NSTX

Issue Reason NSTX Approach

High- stabilitySustain high plasma pressure at low magnetic field

Passive plates,Error-field correctionActive RWM control

Fast particle stability and confinement effects

vNBI/vA>1 → AE modes;

also low-n, multiple modes

Establish stability boundariesDevelop phase space control

Electron confinement

Ion transport predicted and found to be near neoclassical

Measure and understand electron-scale turbulenceRoles of q(r), Er shear in micro-instability control

High divertor heat fluxes

Compact divertor (P/R approaches ITER level)

Radiative divertorLithium coatings and PFCs

Non-inductive operation

No room for conventional solenoid in compact reactor

CHI for start-upRFCD for ramp-upNBCD+BS for sustainment

Bell / IFS / 070306 7

NSTX Extends the Stability Database Significantly

• Seeing benefits of– Low aspect ratio– Cross-section shaping– Stabilization of external modes by conducting plates

Normalized current Ip/a·BT (MA/m·T)

T = 2µ0<p>/BT02 (%) • A = 1.5

• = 2.3

• av = 0.6

• q95 = 4.0

• li = 0.6

• N = 5.9%·m·T/MA

• T =40% (EFIT)34% (TRANSP)

Bell / IFS / 070306 8

Optimized Plasma Shaping Can Increase P and Bootstrap Current Fraction at High T

Divertor coil upgrade2004 2005

Vertically stable operating space

li

= 3.0, X= 0.8li = 0.45

Verticallyunstable

fNI=100%

target

D. Gates et al., NF 46 (2006) 17

• High elongation reduces BP,av = µ0Ip/∫Cdl, increases bootstrap current– Sustained 2.8 for many twall by fast feedback

• Higher triangularity and proximity to conducting wall allows higher N

• Plasma rotation maintains stabilization beyond decay-time of wall current

Bell / IFS / 070306 9

NSTX Approaches Normalized Performance Needed for a Spherical Torus - Component Test Facility

(ST-CTF)

Design optimization for a moderate Q driven ST-CTF:

• Minimize BT required for desired wall loading Maximize <p>/BT2 = T

• Minimize inductive current Maximize fbs 0.5P

• Do this simultaneously Maximize fbsT 0.5PT

Goal of a driven ST-CTF: DT neutron flux = 1 – 4 MW/m2

Achievable with:A = 1.5, = 3, R0 = 1.2m, IP = 8 – 12MA

N ~ 5 %.m.T/MA, H98y,2 = 1.3

T = 15 – 25%

fBS = 45 – 50%

WL= 1 MW/m2 4 MW/m2

App

roxi

mat

e B

oots

trap

Fra

ctio

n

f bs

= 0

.30

.5 p

ol

Bell / IFS / 070306 10

High Performance Has Been Sustained For Several Current Redistribution Times at High Non-

Inductive Current Fraction

p and NBI current drive provide up to 65% of plasma current• Bootstrap current accounts for ~50%

• High NH89P now sustained for up to ~5 current relaxation times

Non-inductive current fractions(TRANSP with classical thermalization)

D. Gates, PoP 13, 056122 (2006)

0.0 0.5 1.0 1.50.0

0.5

1.0

Time (s)

116318A13

Bootstrap(NCLASS)

∇pNB-driven

Currentfraction

1

0

Ip(MA)

PNBI(MW)/10

Ohmic

Bell / IFS / 070306 11

Both Internal and External Modes Can Limit

Resistive Wall Modes can limit T at low-q

Maintaining high plasma rotation is key to stabilizing both modes

Non-linear M3Dsimulations consistent

with experimentT (%)

Mode B(G)

q0

(EFIT w/o MSE)

f(0) (kHz)

Discharge collapses as rotation flattens and decreases

S. Sabbagh et al., NF 44 (2004) 560

Bell / IFS / 070306 12

Error Field Correction by External CoilsExtends Duration of High-Performance Plasmas

J. Menard et al., IAEA 2006

Plasma rotation sustained bycorrection of intrinsic error fields

Stabilizingplates

Blanketmodules

Control coils

0 1 2R(m)

Z(m)

0

-1

-2

1

2

ITER shapeboundaryvessel

NSTX ITER

6 ExternalControl Coils

48 InternalBP, BR sensors

Copper stabilizing plates

Bell / IFS / 070306 13

Resistive Wall Mode (RWM) Actively Stabilized

at Low, ITER-Relevant Rotation•Reduce NB-driven rotation by magnetic braking– Apply non-resonant n=3 field perturbation

•RWM becomes unstable when rotation drops below critical value– No-wall -limit computed by DCON code using measured profiles

•Data from internal sensors detects mode in real-time

•Feedback system applies correcting n=1 field perturbation with appropriate amplitude and phase

S. Sabbagh et al., PRL 97 (2006) 04500

Bell / IFS / 070306 14

NSTX Provides a Novel Vantage Point from which to View Plasma Transport and

Turbulence• Operates in a unique region of dimensionless parameter space:

R/a, T, (,

– Large range of T spanning e-s to e-m turbulence regimes

• Dominant electron heating with NBI

– Relevant to -heating in ITER

• Strong rotational shear affects transport

– Ion transport aproaches neoclassical

– Electron transport anomalous

• Localized electron-scale turbulence measurable (e ~ 0.1 mm)

Bell / IFS / 070306 15

Scans carriedout at constantdensity, injectedpower (4 MW)

0.50 s 0.50 s

H-mode Confinement Scaling Experiments Have Isolated the BT and Ip Dependences

S. Kaye et al., IAEA 2006

Bell / IFS / 070306 16

... Revealing Differences from Conventional Tokamaks

Strong dependence of E on BT

E,98y,2 ~ BT0.15

H98y,2 ~ 0.9 → 1.1 → 1.4

4 MW

E,98y,2 ~ Ip0.93

H98y,2 ~ 1.4 → 1.3 → 1.1

Weaker dependence on Ip

NSTX exhibits stronger E scaling at fixed q: E ~ Ip1.3-1.5

than ITER H-mode scaling: E,98y,2 ~ Ip1.1

4 MW

Bell / IFS / 070306 17

Dimensionless Parameter Scans Address High-Priority ITPA Issues

-scan at fixed q, BT

- -dependence important to ITER advanced scenarios (B98y2~-0.9) - Factor of 2-2.5 variation in T

- Degradation of E with weak on NSTX

20% variation in e, e*

e-scan at fixed q

- Factor of >3 variation in e*

- Strong increase of confinement with decreasing collisionality

=2.1=0.6

S. Kaye et al., IAEA 2006

Bell / IFS / 070306 18

Near-Neoclassical Ion Transport Primarily Governs Ip Scaling

i,GTC-NEO (r/a=0.5-0.8)

GTC-Neo calculation includes finite banana

width effects (non-local)

Bell / IFS / 070306 19

Variation of Electron Transport Primarily

Responsible for BT ScalingBroadening of Te & reduction in e outside r/a=0.5 with increasing BT

Ions near neoclassical

Neoclassical

Bell / IFS / 070306 20

Calculations Suggest ETG May Play an Important Role in Determining Electron Transport at Low BT

Non-linear simulations (up to 250e) show formation of radial streamers

• FLR-modified fluid code [W. Horton et al., PoP 11 (2004)]

• Good agreement between experimental and theoretical saturated transport level at 0.35 T

• Experimental e profile at 0.35 T consistent with prediction from e-m ETG theory [W. Horton et al., NF 45 (2005)]

- Not consistent at higher BT

GS2 calculations show ETG linearly unstable only at lowest BT • 0.35T: R/LTe 20% above Te,crit

• ≥0.45T: R/LTe 20-30% below Te,crit0.35 T

GS2

J.H. Kim et al., APS-DPP, Philadelphia, Oct. 2006

Bell / IFS / 070306 21

Now Beginning to Make Measurements of Turbulence Extending to Electron Gyro-radius

Scale

~

Both ion and electron transport decreaseat transition from L- to H- mode

ELMs

H. Park et al., APS-DPP, Philadelphia, Oct. 2006

r/a

- Localized measurement (r ≈ 6cm) - Adjustable from axis to outer edge

Electron transport remains anomalous

Ion transport close toneoclassical duringH-phase

1mm microwave forward scattering system shows fluctuations (ñ/n) reduced in upper ITG/TEM and ETG k-ranges during H-mode

Bell / IFS / 070306 22

Strongly Reversed Magnetic Shear L-mode Plasmas Have Higher Te and Reduced Transport

Linear GS2 calculations indicatereduced region of micro-tearing instability for RS plasma

GS2 also indicates ETG stabilized by RS

F. Levinton, invited talk ZI1.3, APS-DPP, Philadelphia, Nov. 2006

Bell / IFS / 070306 23

Pellet Perturbations Used to Probe Relation of Critical Gradient Physics to q-Profile

H-mode with monotonic q-profile exhibits stiff profile→ Te close to

marginal stability

Soft X-ray arraydiagnoses fast Te

R/LTe

t=297→301 ms

R/LTe

t=440→444 ms

Reversed magnetic shear L-mode shows steepening of profile with increasing central Te

D. Stutman, Phys. Plasmas 13, 092511 (2006)

Bell / IFS / 070306 24

Multi-mode TAE bursts in NSTX induce larger fast-ion losses than single-mode bursts

1% neutron rate decrease 5% neutron rate decrease

• ITER will operate in new regime for fast ion transport– Fast ion transport expected from interaction of many modes

– NSTX can access multi-mode regime via high fast / total and vfast / vAlfven

NSTX Accesses Fast-Ion Phase-Space Regime Overlapping With and Extending Beyond ITER

E. Fredrickson, Phys. Plasmas 13, 056109 (2006)

0

1

2

3

4

5

6

0.0 0.2 0.4 0.6 0.8

CTF

ARIES-ST

NSTXITER

fast(0) / βtot (0)

Vfast

/ VAlfv

én

0

1

2

3

4

5

6

0

1

2

3

4

5

6

0.0 0.2 0.4 0.6 0.8

CTF

ARIES-ST

NSTXITER

βfast(0) / βtot (0)

Vfast

/ VAlfv

én

Bell / IFS / 070306 25

Alfvén Cascades (RSAE) Observed at Low e on NSTX

• Frequency chirping indicates evolution of qmin– Analysis with successive modes verifies profile reconstruction with MSE constraint

• Modes also observed on MAST

Bell / IFS / 070306 26

“Angelfish” MHD Phenomenon Identified as Form of Hole-Clump, Consistent with Theory

• Mode satisfies Doppler-shifted resonance condition for TRANSP calculated fast ion distribution

• Growth rate from theory in reasonable agreement with observation

• Engineering of fast-ion phase space can suppress deleterious instabilities

H. Berk, IAEA-FEC, Chengdu, (2006)

Bell / IFS / 070306 27

Divertor Power Loading Critical Issue for the ST – High P/R

Conduction DominatedDivertor

Radiation DominatedDivertor

Peak heat flux increases with poweras outer leg becomes connected

PLoss (MW)

qSOL, m-p (cm)

Kallenbach

Counsell

collisionless

collisional

Midplane heat flux SOL in NSTXbroader than models predict

R. Maingi et al., PSI Conf. 2006

Bell / IFS / 070306 28

Peak Heat Flux Can Be Reduced By Plasma Shaping

•Compare configurations with different triangularity at X-point X–lower single-null, X ≈ 0.4

–double-null, X ≈ 0.4

–double-null, X≈ 0.75 high triangularity

•Flux expansion decreases peak heat flux

1 : 0.5 : 0.2 despite reduced radius

•ELMs: Type I Mixed Type VMeasure heat flux to divertor with IR thermography of carbon tiles

R. Maingi et al., PSI Conf. 2006

Bell / IFS / 070306 29

Gas Puffing Near X-point Can Produce Radiative Divertor Without Affecting Core

Confinement

V. Soukhanovskii et al., IAEA 2006

Bell / IFS / 070306 30

Lithium Evaporated on PFCs Produced Particle Pumping and Improved Energy Confinement in

H-mode Plasmas

H98y,2 = 1.1 → 1.3

Lithium Evaporator

R. Majeski et al., IAEA 2006; H. Kugel et al. APS-DPP, Philadelphia, Nov. 2006

Effect transient and did not increase with amount of lithium

Bell / IFS / 070306 31

Imaging of Plasma Edge Contributing to Understanding Edge Turbulence Phenomena

(Blobs, ELMs) Measurements of “blob” propagation

connect to evolving theoryELM dynamics and rotation

have been measured

R. Maqueda, R. Maingi, S. Zweben, D. Stotler

Bell / IFS / 070306 32

Ways to Initiate, Ramp-up and Sustain Plasma Current without Reliance on Central Solenoid

Critical for the ST

CHI or PF-only for plasma initiation

and early ramp-up

IIPP

timetimeHHFWHHFW HHFW+NBIHHFW+NBICHICHI

200 kW 200 kW ECH/EBWHECH/EBWH

HHFW for ramp-up of low Ip plasma

(bootstrap + FWCD)

CHI: Co-Axial Helicity Injection

ECH/EBW: 28/15.3 GHz, 200 kW system planned (2009)

HHFW: 30 MHz (~20th D harmonic), 6 MW

NBI: effective with enough current to confine ions

Bell / IFS / 070306 33

CHI Can Initiate Plasma Current Without Induction

• Initially investigated and developed in HIT and HIT-II devices at U. Washington

• Toroidal insulating breaks between inner, outer vacuum vessel in NSTX

• Transient CHI: Axisymmetric reconnection during decay of injected current leads to formation of closed flux surfaces

Bell / IFS / 070306 34

Transient CHI Has Now Produced 160 kA of Closed-Flux Current in NSTX

Once ICHI0, EFIT reconstruction using external magnetic sensors tracks dynamics of detachment from

injector & resistive current decay

R. Raman et al., PRL 97 (2006) 175002

Toroidal plasma current remaining after ICHI→0 flows on closed surfaces

5 10 15Time (ms)

300

250

200

150

100

50

0

Ip

ICHI

kA

Current decay rate consistent with resistivity of plasma 10 – 20 eV

Bell / IFS / 070306 35

EBW Coupling to External Antenna Investigated Using Mode Conversion of Thermal EBW in Plasma

Coupling via B-X-O conversion

well modeled in L-mode at fce

Coupling in H-modelower than predicted

SimulatedTrad

Measured Trad

uncertainty

Time[s]

2

1

00 0.2 0.4

0

0.2

0.4

0.8

1.0

0.6

0

1

2

Trad

[keV]

0

0.2

0.4

0.6

0.8

1.0

ConversionEfficiency

Simulated Trad

Measured Trad

uncertainty

15.5 GHz(f )ce

25 GHz(2f )ce

Trad

[keV]ConversionEfficiency

Time (s)0.0 0.2 0.4

App

arent coupling efficie

ncy

Time [s]0 0.2 0.4 0.6 0.8 1.0

0

0.2

0.4

0.6 H-mode

Trad

[keV]

15.5 GHz(f )ce

0.30.3

0.20.2

0.10.1

0.00.0

App

arent coupling efficie

ncy

•Conventional ECCD not possible in “overdense” (pe > ce) ST plasmas

•Electron Bernstein waves (EBW) can propagate and be absorbed in plasma to produce current drive for NSTX goal, but

•EBW-CD relies on mode conversion from externally launched e.m. waves

G. Taylor; S. Diem APS-DPP, Philadelphia, Nov. 2006

Bell / IFS / 070306 36

We

(kJ)

Heating Efficiency of HHFW Improved at High BT and k||

At fixed BT = 0.45T, electron heating efficiency degrades at lower k|| (higher vph)

At fixed k|| = 7m-1, electron heating

efficiency improves

at higher BT

Time (s)

Constant PRF≈2MW

BR

F (

a.u.

)

kk||||==3 m-1

7 m-1

14 m-1

0.20.1

2

1

0

Magnetic probe at edge detects RF signal from

Parametric Decay Instability

• Need directed waves with k|| = 3.5 – 7m-1 for HHFW-CD current drive

J. Hosea, APS-DPP, Philadelphia, Nov. 2006

Bell / IFS / 070306 37

NSTX Achieves Many High-Performance Plasma Features Simultaneously for Extended Pulses

High Confinement

High Non-inductive Fraction

High N

Stable Boundary

CR

NSTX “Hybrid”-like scenario as proposed for ITER

Bell / IFS / 070306 38

MHD-Induced Redistribution of NBI Current Drive Contributes to NSTX “Hybrid”-Like Scenario

Proposed for ITERqmin>1 for entire discharge, increases during late n=1 activity

•High anomalous fast ion transport needed to explain neutron rate discrepancy during n=1

•Fast ion transport converts peaked JNBI to flat or hollow profile

•Redistribution of NBICD makes predictions consistent with MSE

J. Menard, PRL 97, 095002 (2006)

n=1 mode onset

n=1 mode onset

Bell / IFS / 070306 39

n(0)=0.75e20

•Achieved (116313)n20(0)=0.85=2.2 H98=1.1 N = 5.6q(0) = 1.15

Integrated Modeling Points to Importance of Shaping, Reduced ne, and Increased Te/E for

Higher fNI and High N

•Higher , En20(0)=0.75 =2.55H98=1.35N = 6.6q(0) = 1.4

•Lower densityn20(0)=0.36 =2.2H98=1.1 N = 5.6q(0) = 1 @ 0.8 s

TotalTotal NICDBootstrapNBCDp

C. Kessel, Invited talk, APS-DPP, Denver, Oct. 2005

Bell / IFS / 070306 40

NSTX Normalized Performance Approaches Required Level for ST-CTF

• Advanced mode stabilization methods and diagnostics are being applied to improve performance

– Dynamic Error Field Correction and RWM feedback suppression

• Unique tools available to study transport and turbulence

– Excellent laboratory in which to study core electron transport

• Investigating fast-ion instabilities with full diagnostics, including MSE for q-profile

– Capability to mimic ITER situation

• Developing non-inductive startup and sustainment schemes

– CHI, EBW, HHFW

• Developing methods for heat flux and particle control

– Lithium, radiative divertors

• NSTX also contributes to several high-priority issues for ITER

Bell / IFS / 070306 41

STs Can Lead to Attractive Fusion Systems

• Component Test Facility (CTF) will be needed after ITER to carry out integrated DEMO power testing and development

• ST enables highly compact CTF with full remote maintenance and high duty factor, and it provides potentially attractive reactor configuration

M. Peng et al, PPCF 47, B263 (2005)

Bell / IFS / 070306 42

During Magnetic Braking, Rotation Profile Follows Neoclassical Toroidal Viscosity

(NTV) Theory

•First quantitative agreement with NTV theory

– Due to plasma flow through non-axisymmetric field

– Trapped particle, 3-D field spectrum important

– Computed using experimental equilibria

•Necessary physics for simulations of rotation dynamics in future devices (ITER, CTF)

Magnetic braking due to applied n=3 field

W. Zhu et al., PRL 96 (2006) 225002

Bell / IFS / 070306 43

Increased Ion Collisionality Decreases Critical Rotation Frequency crit

•Plasmas with similar vA

•Consistent with neoclassical viscous dissipation model– at low , increased i leads to lower crit

•ITER plasmas with lower i may require higher degree of RWM active stabilization

(K. C. Shaing, Phys. Plasmas 11 (2004) 5525.)

Sontag, et al., IAEA 2006

Further analysis aimsto uncover RWM stabilization physics

(a)

(b)

(c)

crit(km/ )s

vA (km/ )s

ii (kHz)

121083121071

Bell / IFS / 070306 44

Low A, High Favorable for Study of NTM Seeding / Stabilization

• Several types of event can initiate low frequency MHD modes in NSTX

– e.g. sawteeth*, RWMs**– Can led to soft beta limit, or rotation reduction resulting in disruption

– Large q = 1 radius, high , mode coupling at low-A facilitate seeding

– NTM stabilization amplified at low-A (GGJ 3/2) – NTM less deleterious

• NTM study planned 2007 - 2009– Characterize modes: NTMs, TMs, or internal kinks?

– Exploit 12 channel MSE, reflectometer, fast USXR capabilities

– Mitigate deleterious effects of modes

n=1

Sawtooth excitation of n = 2

• Sawtooth excites n = 2, but n = 2 can decrease post-crash

*Fredrickson, et al., APS-DPP 2004; **Sabbagh, et al., NF 44 (2004) 560

Bell / IFS / 070306 45

Reflectometry Data Reveals 3-wave Coupling

of Distinct Fast-Ion Instabilities

• Large EPM TAE phase locks to EPMforming toroidally localized wave-packet• Low-f EPMs co-exist with mid-f

TAE modes

Influence of toroidal localization of TAE mode energy on fast ion transport and EPM/TAE stability presently being

investigated

Bi-coherence analysis reveals 3-wave coupling between 1 EPM and 2 TAE modes

N. Crocker, Phys. Rev. Lett. 97, 045002 (2006)

EPM Energetic Particle Mode (bounce-resonant fishbones)

TAE Toroidal Alfven Eigenmode

Bell / IFS / 070306 46

Identification of -Induced Alfvén-Acoustic Eigenmodes (BAAE)

• Energetic particle driven modes often seen at frequencies lower than those expected for TAE

• Couples two fundamental MHD branches (Alfvén & acoustic)

• Joint studies planned with JET

Bell / IFS / 070306 47

FY 07 Facility Enhancements

• Higher temperature bakeout of divertor tile to improve plasma performance and to prepare for lithium

– Lower divertor tiles to 350°C and upper tiles to 240°C

• Faster lithium evaporation

– x10 deposition rate to lower divertor plates

– Evaporation between/during shots in normal cycles

• Higher Mach number for supersonic gas injector to improve fueling for H-mode (LLNL)

• Higher voltage for higher current CHI (U Washington)

– Improved monitoring of voltage transients

• Faster processors for real-time plasma control system (GA)

– Aiming to operate in parallel by end of FY07 run

Bell / IFS / 070306 48

• Poloidal CHERS (27 ch) for transport physics

• MSE 12 16 channels for improved j(r) resolution (Nova)• Transmission grating x-ray spectrometer viewing across NBI for impurity transport (JHU)

• FIDA (Fast Ion Dmeasurement) - fast, band-pass-filtered channels for the local fast-ion density (prototype channels late in ‘07 run) (UC Irvine)

• FIReTIP 4 6 channels (500 kHz) for improved spatial resolution (UC Davis)

• New collection mirror for high-k scattering system

• Correlation reflectometer, fixed freq. reflectometer (3 6 ch), profile reflectometer (25 10s) and high-k backscattering (late in the run) (UCLA)

• Improved high-frequency Mirnov coil system for energetic particle modes and segmented Rogowski coil for disruption study

• Wider-angle view and local gas-puffing for EBW radiometers for H-mode coupling

• 3 RF probes to measure surface waves during HHFW heating

• Additional divertor filterscope fast channels (24-32 total) (ORNL)

FY 07 Diagnostic Enhancements