Study of transport simulation on RF heated and current driven EAST

plasmaSiye Ding

Under instruction of Prof. Baonian Wan12/09/2009

Outline

• TRANSP & pTRANSP program

• Feature of NSTX plasma --- Transport analysis work at PPPL

• Preliminary results of EAST simulation

• Summary

TRANSP

• Category: Experimental Data Analysis• TRANSP descended from BALDUR in the 1970s • The complete system includes:

– A million lines of FORTRAN code– Over 100 executable programs– Over 100 subroutines– More than 100 Man-Years invested in developing code

• Language code: Fortran-77, Fortran-90 and some C, C++ and Python

• A time dependent 1½D tokamak transport data analysis model with generalized non-circular flux surface geometry

• Auxiliary heating packages– NUBEAM, TORIC, LSC, TORAY

PTRANSP

• Predictive TRANSP– The ability of simulating numerous kinds of fusion pla

sma activities– Inputs: Tokamak Simulation Code (TSC) outputs

• Shaped boundary (required)• Other self-consistent plasma parameters (optional)

– The same namelist with different options– Equilibrium: TEQ– Temperature and transport model options: GLF23, M

MM95, Weiland model, NClass neoclassical model, paleoclassical model, etc.

– Density: assumed

Feature of energy transport in NSTX

plasma• Data selection

• dependence at constant Bt

• The influence of plasma current profile on

• The ‘pivot’ phenomenon in profile

• The influence of lithium on energy transport

dependence on Bp (or q)

• Parameters: Ip(900kA),

Bt (0.48T), Pheat(5.6MW), and

<ne> (4.6~5.61013cm-3),

<Te> (490~608eV)• A significant influence of ngTx in the

relation between s and Bp (or q)– ngTx: the abbreviation of ‘local -ne*

Ti/e’ value– units: Bp in T, ne in 1013cm-3, Ti/e in eV, r i

s normalized magnetic surface

• The proportional relation between and Bp (or the inversely proportional relation between and q )

dependence on plasma current

• Pcond vs ngTx and q at constant Bt and different Ip

– No obvious dependence on Ip

– Plasma current profile• Constant ngTx

–

–

• Constant q• Peaky and flat

(hollow) profile

pxIjngTx

pxIq 1

The ‘pivot’ phenomenon in eprofile

• Governed by local current density (or current profile) – Data at constant Bt (2008)

– Data at different Bt (2006) Ip=900kA Ip=1100kA

Data at different Bt (2006)

The influence of lithium on energy transport

• Energy confinement time– Parameters:

• Ip (kA): 800, 900

• Bt (T): 0.54(max), 0.51(avg), 0.48(min)

• Pheat (MW): 4.3(max), 3.7(avg), 3.2(min)

– E increases

– 0mg: without-lithium data

• Radiated power– Local e decreases

– Large percentage of radiated power

– No obvious improvement on i

The influence of lithium on energy transport

• e (direct comparison)– More than 50% reduction

• i (indirect comparison)– Effective

• The third lithium state

Ip: 900kABt: 0.47TPheat: 5MW

Ip: 900kABt: 0.49TPheat: 3.6MW

EAST simulation

• Shot#12467:– 250kA; 1.9T;1.1e19m-3; LSN, DN, USN; Ohmic

• Shot#12755:– 500kA; 1.9T; 2.5e19m-3; DN; PLH: 450kW

• Theoretical transport model:– GLF23 (mainly)– MMM95– RLW-M

EAST simulation: 12467flux contour

A

B

C

D

E

EAST simulation: 12467flux contour

A

B

C

D

E

EAST simulation: 12467flux contour

A

B

C

D

E

EAST simulation: 12467p, li and current profile

• Some difference between TRANSP (TSC) and EFIT

EAST simulation: 12467different models and experiment

data

EAST simulation: 12467ne and Ti/e profile

• ne profile: assumed by using parabolic distribution with two free index parameters

• Ti0: assumed to be 2/3~3/4 Te0

EAST simulation: 12467confinement

EAST simulation: 12467power balance

• Electron:– Source: Ohmic electron heating– Sink: i-e coupling, conduction

• Ion:– Source: i-e coupling– Sink: conduction, charge exchange loss

• The theory model for radiation prediction is not effective enough.

EAST simulation: 12467energy transport

EAST simulation: 12755LH wave injection

• Absorbed LH power: 85% injected LH power, similar to Ohmic power

• Deposition position of LH power: ~0.1 and ~[0.3, 0.65]

EAST simulation: 12755LH current

• IOh: 400kA; ILH: 80kA; IBS: 20kA

• CD=9.95e18 AW-1m-2

EAST simulation: 12755region of LHW

absorption

• 5% LH power was deposited around ~0.1, that can not be explained in this figure.

EAST simulation: 12755theory model and experiment

data

EAST simulation: 12755high power plasma

• ICRH: minority heating scheme

• L-H transition threshold: Ploss~1.1MW

NBI simulation

Summary

• Brief instruction of TRANSP/pTRANSP program• Plasma current profile affects values, including

the ‘pivot’ phenomenon, via ngTx.• Lithium can improve energy confinement time, en

hance radiation and reduce e more than 50% when large quantities are injected. For i, it is effective, but not quantitative investigated.

• The relatively reasonable results are obtained in EAST simulation comparing with experiment data.

• More detailed physical analysis and operation design are under consideration.

Acknowledgement

• PPPLers:– Analysis: Stanley Kaye and the NSTX team– Prediction: Robert Budny– TRANSP settings and jobs monitoring: Dougl

as McCune and the Computational team

• ASIPPers:– Modeling: Xinjun Zhang, Fukun Liu, Jun Li– Experiment data: Ping Xu, Jianhua Yang, Xia

ofeng Han, Jinping Qian– TSC output: Yong Guo

Thank you !