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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 !