Overview of Magnetic Fusion Simulation in China

J. Q. Dong

Southwestern Institute of Physics

China

The Workshop on ITER Simulation

May 15-19, 2006, Beijing, China

Outline1, Introduction2, Confinement3, Stability 4, Divertor and Edge Physics5, Wave Heating, Current Drive and Fuelling6, Others7, Summary

1, Introduction A, Institutions and universities

• Southwestern Institute of Physics (SWIP), Chengdu• Institute of Plasma Physics (IPP), Hefei• University of Science and Technology of China (US

TC), Hefei• Tsinghua University (THU), Beijing• Dalian University of Technology (DUT), Dalian• Huazhong University of Science and Technology (H

UST), Wuhan• Institute of Physics (IP), Beijing• PKU, ZJU, NKU & NHU

B, Devices

• HT-7 (IPP)

• SUNIST (THU)

• HL-2A (SWIP)

• EAST (IPP)

• J-TEXT (HUST)

HT-7

SUNIST device

SUNISTSUNIST

SUNIST main parameters:

major radius R 0.3m

minor radius a 0.23m

Aspect ratio A ~1.3

elongation κ ~1.6

toroidal field （ R0） BT 0.15T

plasma current IP 0.05MA

central rod current of BT IROD 0.225MA

flux (double swing) ΔΦ 0.06Vs

HL-2A

R=1.65 m, a=40 cm, Ip=350 kA, Bt=2.5 T, td=2s

• EAST

J-TEXT

• From TEXT-upgrade, FRC, U-Texas

• R=1 m, a=26 cm, Ip=300 kA, Bt=2.5 T

C, Present Status of magnetic fusion simulation

• With a small scale, mainly at IPP and SWIP

• At a starting stage,

1) more universities are eager to participate

2) the big experiment program has to be supported by theory and simulation

2, ConfinementWorks on MHD Equilibrium

• Theory of tokamak equilibria with central current density reversal (Wang, PRL, 2004)

• Analytic description of high poloidal beta equilibrium with a natural inboard poloidal field null (Shi, PoP, 2005)

• Tokamak MHD equilibria with toroidal flow or sustained by high fraction bootstrap current (Ren, PST, 2006 and Shi, CPL, 2003)

2.1. MHD equilibrium (1)

• MHD equilibrium configurations of EAST were simulated with the EFIT code.

EASTASIPP

(a) SN configuration (b) CDN configuration

The schematic EAST divertor geometry and the computational mesh

10135020重点基金结题

t=0 t=0.584 s t=1.29 s

t=1.99 s t=4.11 s

2.1. MHD equilibrium (2)• the HL-2A equilibrium configurations

calculation with the SWEQU code

the HL-2A equilibrium configurations reconstruction with the EFIT code

2.2. Micro-instabilities and turbulence (1)

• Electrostatic and electromagnetic micro-instabilities (ITG, ETG, TEM, AITG, SWITG, SWETG) are studied with fluid and kinetic theories

• Formation of large-scale structures in (ETG) turbulence: zonal flows or streamers, and the role of magnetic shear in the formation dynamics are numerically demonstrated.

2.2. Micro-instability and turbulence (2)

Te critical vs. Te/Ti & R/Ln

ce

TeL

R

3/ ie TT

2/ ie TT

1/ ie TT3/1/ ie TT

2.2. Micro-instability and turbulence (3)

JET experiment results

Micro-instability and turbulence (4) Formation of large-scale structures

Streamer-like bump Zonal flowZonal flow-like bump

Streamers

Modulation instability analysis show: Structure selection depends on spectral anisotropy of ETG fluctuations

Magnetic shear governs spectral anisotropy of ETG; Structure selection of zonal flows or streamers

Zonal flow dominated Homogeneous ETG streamer dominated

2.3. Predictive transport modeling (1)

• Reversed shear configuration formation on EAST

2.3. Predictive transport modeling(2)

• Quasi-stationary RS operation establishment with current profile control on HL-2A

• Development of double transport barrier in shaped plasmas of HL-2A

0.5 1.0 1.50

Ip

PNB

PLH1.0

2.0P(MW)

1.0

2.0

Vp(v)67

134

201

268Ip(KA)

t(s)

Fig.1.1 Waveforms of the plasma current Ip, loop voltage Vp, the NBI power PNB, and the LH wave power PLH

Fig.1.2 Magnetic geometry of the discharge

A steady-state RS discharge is formed and sustained with 6.0minx and 8.2minq (p p()/0 =3.0 - 3.2) until the LH

power is turned off.

0.0 0.5 1.00

50

100

0.5

1.0

1.5

x

t(s)

jLH(A/cm )2

(a)

0.2 0.4 0.6 0.8 1.0

3

4

5

6q

t(s)

t=0.8s1.0s1.4s1.78s

(b)

Fig.1.3 (a) The temporal evolution of LH wave driven current profile, and (b) q profiles at different times for the sustained RS discharge

The double transport barrier is indicated by two abrupt decreases of the ion heat diffusivity, of which the two minima are located near the shear reversal point, min 0.55, and near

the plasma edge, 0.95, respectively. The elevated heat diffusivity between the two minima separates the two barriers.

Fig.2.3 Profiles of q and ion heat diffusivity, i (at

t=1.0s) for the elongated D-shape plasma.

2.4. Analysis of plasma relaxed states for inductively driven tokamaks of arbitrary aspect ratio

• A variety of current profiles observed in tokamak experiments are reproduced theoretically form principle of minimum dissipation rate subject to helicity and energy balance. (Zhang)

2.5. New Coulomb logarithm and its effects• New Coulomb logarithm and its effects on the Fokke

r-Plank equation, relaxation time and cross field transport (Li)

3, Macro-instabilities

3.1. Vertical displacement instability analysis of EAST

3.7 3.8 3.9 4.0 4.1 4.20.0

0.4

0.8

1.2

Value

time / s

Ip (MA)

Zmag

(m)

3.7 3.8 3.9 4.0 4.1 4.20.0

0.4

0.8

1.2

1.6

2.0

3.7 3.8 3.9 4.0 4.1 4.20.0

0.4

0.8

1.2

1.6

2.0

Val

ue

time / s

p

li/2

Val

ue

R0 (m)

a (m)

3.2. Resistive TM and flow layer formation( )

Evolution of magnetic island width and amplitude of velocity shear

0 500 1000 1500 2000 2500 3000 3500-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

S=106S=105

t0 1000 2000 3000 4000

-2

0

2

4

6

8

10

12

14

16

s=106

s=105

(dv

y/dx)

max

t

)(/1 0 xj

Contour of

-0.4 -0.2 0.0 0.2 0.40

3

6

9

12

s=105,t=500(x,y)

-0.04000

-0.03000

-0.02000

-0.01000

3.469E-18

0.01000

0.02000

0.03000

0.04000

x

y

-0.4 -0.2 0.0 0.2 0.4

-10

-5

0

5

10

s=106,t=1000(x,y)

-0.04000

-0.03000

-0.02000

-0.01000

3.469E-18

0.01000

0.02000

0.03000

0.04000

x

y

-0.4 -0.2 0.0 0.2 0.4

0

3

6

9

12

(x,y) s=105,t=1000

-0.05500-0.05200-0.04900-0.04600-0.04300-0.04000-0.03700-0.03400-0.03100-0.02800-0.02500-0.02200-0.01900-0.01600-0.01300-0.01000-0.007000-0.004000-1E-30.0020000.0050000.0080000.011000.014000.017000.020000.023000.026000.029000.032000.035000.038000.041000.044000.047000.050000.053000.056000.059000.06000

x

y

-0.4 -0.2 0.0 0.2 0.40

3

6

9

12

s=106,t=3000(x,y)

-0.06000-0.05500-0.05000-0.04500-0.04000-0.03500-0.03000-0.02500-0.02000-0.01500-0.01000-0.005000-5.204E-180.0050000.010000.015000.020000.025000.030000.035000.040000.045000.050000.055000.06000

x

y

Profiles of velocity shear

• Assuming

we estimated

• This is comparable with the turbulence suppression shearing rate

-1.0 -0.5 0.0 0.5 1.0

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0 s=105,t=500dv

y/dx

x-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0 s=106,t=1000

dvy/d

x

x

arqmRTBcmn se 25.0,2,6.1,5.2,/103 313

sxvy /107/ 5

3.3. Fast particle MHD

• Destabilization of internal kink modes at high freq

uency by energetic circulating ions (Wang, PRL 20

01)

• Sawtooth stabilization by barely trapped energetic

electrons (Wang, PRL 2002)

• Fish bone instability driven by energetic electrons

(Wang, Z.T., PST, 2005 )

4, Divertor and Edge Physics

• EAST SOL/Divertor physics analysis (Zhu)• HL-2A SOL/Divertor physics analysis (Pan)• Atomic and molecular physics:The neutral tra

nsport modeling was performed for the HT-7 hydrogen removal experiment with DEGAS2 code .

5, Heating, Current Drive and Fuelling

5.1. ECRH and LHCD, Fokker-Planck study of tokamak ECRH & LHCD were performed for the HL-2A tokamak discharges (Shi & Jiao)

5.2. Ion cyclotron resonance heating (ICRH) (Ding)

5.3. Synergetic simulation of LHW and IBW/ICRF (Ding)

5.4. Penetration and deposition of a supersonic molecular beam in the HL-1M tokamak: The supersonic molecular beam (SMB) ablation and penetration processes in HL-1M tokamak experiments were studied (Jiao, PPCF, 2003)

5.5. Neutral beam relaxation analysis

6,Others

• Simulation of collisionless shock wave with ideal MHD equations (Yang)

7, Summary7.1. Code development and import 1) MHD equilibrium codes SWEQU & TOQ2) MHD equilibrium reconstruction code EFIT 3) Gyro-fluid code for ETG turbulence studies in a slab4) Linear PIC code TPIC for ETG & ITG in a torus5) Integral eigenvalue code HD7 for ETG, TEM & ITG

in a torus6) Integral eigenvalue code HD7slab for ETG & ITG in

high β plasmas of slab

7) FOKKER-PLANK codes RFP & FPPCRAY with & without relativistic effects

8) Code LSC for LHCD

9) Resistive (viscosity) MHD code DMHD

10) Ideal MHD instability codes GATO & BALLO

11) Edge physics simulation code SOLPS (B2.5+ EIRENE)

12) Plasma surface interaction codes PSIC & DEGAS2

13) Transport code TRANSP

14) MHD shock wave simulation code

7.2. Important topics not touched

1) Resistive wall mode (RWM) & edge localized mode (ELM)

2) Toroidicity induced Alfven eigen-mode (TAE)3)  Ideal and resistive ballooning mode;4) Nonlinear wave-plasma interactions5) Kinetic simulation of turbulence and transport 7.3. Fields have to be emphasized in the future 1) Integrated modeling of tokamak discharges2) Simulation of nonlinear processes in tokamak pl

asmas

7.4. Suggestions

• Enhancing the existing programs• Establishing new institutes for fusion theory and

simulation & encouraging participation of universities

• Establishing a national program • Dividing efforts to two fields: advanced plasma

physics (turbulence & transport, MHD, coherent structure formation, wave plasma interaction, energetic particle physics and edge physics …) and tokamak modeling (modules & integrated simulations for experiments: HL-2A, EAST and ITER)

Thank Professors S.Z. Zhu, G.Y. Yu and D. Li for providing materials!