C. Kessel and E. SynakowskiPrinceton Plasma Physics Laboratory

For the NSTX National Team

APS Division of Plasma Physics MeetingOctober 27-31, 2003

Integrated Scenario Modeling of NSTX Advanced Plasma

Configurations

Supported by

Columbia UComp-X

General AtomicsINEL

Johns Hopkins ULANLLLNL

LodestarMIT

Nova PhotonicsNYU

ORNLPPPL

PSISNL

UC DavisUC Irvine

UCLAUCSD

U MarylandU New Mexico

U RochesterU Washington

U WisconsinCulham Sci Ctr

Hiroshima UHIST

Kyushu Tokai UNiigata U

Tsukuba UU TokyoIoffe Inst

TRINITIKBSI

KAISTENEA, Frascati

CEA, CadaracheIPP, Jülich

IPP, GarchingU Quebec

Non-inductively Sustained, High for flattop >> J Integrated

Advanced ST Plasmas

Ip = 1.0 MA, BT = 0.36 T, N = 8.85, = 41%, PNBI = 4 MW,

PHHFW = 3 MW, PEBW = 3 MW

High and N Operating Targets for flattop > E ST Physics at High

Non-solenoidal Current Rampup Basis for Future ST Devices

Non-inductively Sustained for flattop > J Current Drive Techniques

NBI + HHFW, HHFW only, and HHFW+EBW

Integrated Scenario Modeling is Focused on NSTX Advanced ST Milestones

Shot 109070 Provides Basis for Integrated Scenario Modeling in TSC

Shot 109070 was chosen as a good prototype for longer pulse NBI scenarios

tflat > J for Ip and INI / IP > 50%

N = 5.9, H98 = 1.2

TSC benchmark simulation of 109070

TRANSP, S. Kaye

Strong Suppression of HHFW CD from NB Fast

Ions and for Ti/Te >1

Beam ions absorb 50-98% of HHFW power ----> seen in beam ion energy on experiment

Thermal ions absorb 0-40% of HHFW power ----> no experimental verification so far

Most of the HHFW power is absorbed before waves reach axis, low k|| suffers most

However, HHFW current drive without NBI reaches up to 140 kA/MW

No CD is assumed from HHFW in scenarios that include NBI

NSTX Can Operate for Several Current Relaxation Times Depending on the TF Field

0.0

1.0

2.0

3.0

4.0

5.0

6.0

3 3.5 4 4.5 5 5.5 6

Bt (kG)

Tim

e,

sec

J = 230 ms (109070)

J = 670 msNon-inductively Sustained, High

J = 500 ms Non-inductively Sustained

J oa

212 neo

,neo f Te , f t ,*,Zeff

Accessible TF Coil flattop time

4 J

2 J

=2.6,=0.8+=2.6,=0.4=1.9,=0.8

PF1 Coil Modification Leads to Simultaneous High Elongation and High Triangularity

Present shaping capability PF1 Modification

EBW CD Provides Off-Axis Current Profile Control

G. Taylor, PPPLB. Harvey, CompX

• Lower BT to access high and N values and long pulse lengths

• Inject– 4 MW NB heating and CD on axis– 3 MW HHFW heating (no CD)– 3 MW EBW heating and CD off-axis

• Utilize simultaneous high elongation and high triangularity from PF1 modification

• Assume density control and slight density peaking near plasma edge from lithium pellets or pumping, n(0)/<n> = 1.1

Time-Dependent Simulations of Non-inductively Sustained, High Plasmas in TSC

Non-Inductively Sustained, High PlasmaIntegration Target is Reached

Ip = 1.0 MA, Bt = 0.36 TIBS = 430 kA, INB = 430 kAIEBW = 100 kA = 2.55, = 0.83qcyl = 2.5, li(1) = 0.4

= 41.3%N = 8.85E = 37 msH98 = 1.5

ion

electron

poloidal flux

n(0) n

EBW off-axis current critical for ballooning stability

Reach = 41%, N = 8.85, for 4 J with Ip = 1 MA, BT = 0.36 T

Stable to high-n ballooning* and n=1 kink modes with outboard wall at 1.5a

PF1 coil modification critical to accessing high N by providing high and high together

* except in pedestal region

Pressure Profile and Current Profile Lead to StableHigh Plasma with fNI ≈ 1, Sustained for 4J

V/ Vo

Further Investigations and Development for Integrated Scenario Modeling

• HHFW CD efficiency– Fast ion absorption– Thermal ion absorption– Full wave (AORSA) and

ray-tracing benchmarks

• EBW CD– Continue modeling and

parameter dependences

• Plasma transport– Continue to rely on expt.

’s as discharges move closer to scenarios

– Use NSTX specific global scaling

– Pursue a Low A predictive transport model

• NBI analysis– Apply TRANSP beam

analysis to TSC high cases

• MHD stability– Vertical stability/control

of high plasmas– Identify more accurate -

limits ---> conductors geometry, plasma rotation, higher n RWMs, RWM feedback, FLR & flow stabilization for high-n

NSTX is Using Integrated Scenario Modeling to Plan Future Experiments

• Advanced ST plasmas have been identified– Non-inductively Sustained for flattop > J,

– Non-solenoidal current rampup,

– High and N Operating Targets,

– Non-inductively Sustained, High for flattop ≈ 4 J,

• Ip = 1.0 MA, BT = 0.36 T, N = 8.85, = 41%, PNBI = 4 MW, PHHFW = 3 MW, PEBW = 3 MW

• Critical tools to access Advanced ST plasmas– HHFW heating with NBI, and heating/CD without NBI on/near-

axis– EBW CD off-axis– Strong plasma shaping through PF coil modification– Density control thru pumping or lithium