Status of Fusion Theory and Simulation Research in NFRI

6th J-K Workshop/NIFS/2011

J.Y. Kim

2

Introduction

Major Research Activities and Plan - Turbulent Transport - MHD Equilibrium & Instability - Pedestal & ELM - Integrated Operation Scenario - Divertor & PWI

Summary

3

Major Goal of Theory & Simulation Research

• To develop advanced theoretical models and simulation skills for understanding fusion plasma & material

• To support KSTAR, ITER, and DEMO research programs

• Physics De-sign Valida-tion• Operation Scenario De-velopment

ITER• Experimen-tal Data Analysis• Operation Scenario De-velopment

KSTAR

DEMO • Physics Design & AT Scenario Devel-opment• Advanced Fusion Material Research

4

Projects supporting Theory & Simulation Research

Fusion Simulation Project

• started from 2007 for promoting the simulation research of fusion plasma in NFRI

• annual budget of about 700k$/year (not including the salary of regular staff)

• now supporting mainly the research work of the field, being not covered by WCI project

WCI (World-Class-Institute) Center Project

• government project for promoting the research capability of national institutes

• our center selected as one of the three centers (Fusion, Casncer, Brain)

- Integrated modeling study of turbulent transport in fusion plasmas

• five year project (2009.12- 2014.11), with annual budget of about 2M$/year

• now, about 11 people with 6 foreign and 5 domestic members (Director : Prof. P. Diamond)

KSTAR Project

• mostly for supporting the experimental research and device upgrade of KSTAR

• partial support for the theoretical modeling and data analysis work

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Turbulent Transport

Intensive study being performed through WCI project

- Intrinsic rotation and momentum transport

- Transport barrier formation and evolution (ITB, ETB)

- Non-local transport & self-organization

- Particle and impurity transport

- MHD & turbulence interaction etc.

Strong emphases on the global transport simulation study

- Global gyro-fluid simulation using TRB code (circular, ES, basis-function)

※ plan to develop a more general global gyrofluid code (D-shape, EM, finite-difference)

- Global gyrokinetic simulation using gKPSP code (delta-f, PIC)

※ a full-f gyrokinetic code being developed using semi-Lagrangian method (cf. GYSELA)

- Recently, a parallel PC-cluster system started its operation (from June 29, 2011)

A close collaboration study with KSTAR experimental group

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Global Gyro-fluid Simulation

• TRB code imported and upgraded

- global transport simulation study with a reasonable computation time

- extensive study being done of ITB formation, flow generation & transport etc.

• Global non-local transport study planned of various modes (Ohmic, H, Hybrid etc.)

• Upgrade also planned : circular, Electrostatic => Shaped, Electromagnetic

Power ramp simula-tion

Forward transitionBack transition

[Kim et.al. NF’11]

1st APTWG meeting,S.S. Kim et al

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Global Gyro-kinetic Simulation

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• gKPSP (delta-f, PIC) code developed

- Neoclassical equilibrium & trapped electron effects included

- Intrinsic rotation, momentum transport, particle transport being studied

• A new code (full-f, semi-Lagrangian) under development for the study of

- Global non-local transport modeling from core to edge

- Barrier formation of ITB and ETB, with turbulence & neoclassical effects etc.

r/R0 r/R0

ηi = 1.0 (TEM)

ηi = 3.1 (ITG)

ηi = 1.0 (TEM)

ηi = 3.1 (ITG)

V|| V||

Immediate after nonlinear saturation After nonlinear saturation

1st APTWG meeting,J.M. Kwon et al

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A Parallel PC-Cluster System

HP ProLiant Linix Cluster

(AMD 64bit 12-core 2.2GHz)

Total 576 CPUs (x 12 = 6912

cores) with infiniband QDR in-

terconnection

60TF theoretical peak perfor-

mance, 40 TF HPL

2GBytes/core memory (14

TBytes total)

160 TBytes disk storage

Ranked 423-th in the top 500

(2011. 6)

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MHD Equilibrium and Instabilities

Calculation of 3D error field and perturbed magnetic field for KSTAR

- A detailed calculation of error field performed using OPERA/MAFLO codes

- 3D perturbed field from KSTAR FEC/ELM/RWM coil under calculation using IPEC etc.

Simulation study of Sawtooth, LM, NTM etc.

- Reduced MHD simulation using the 4-field code (in collaboration with Dr. Aydmir in IFS)

- Extended MHD simulation using NIMROD (in collaboration with NIMROD group)

- The codes installed and simulation study just started

Disruption Simulation for KSTAR

- Initial study performed for KSTAR design using TSC code

- Re-calculation being performed with the modified KSTAR passive plate model

Stability Study of Energetic Particle Mode

- NOVA-K imported and a preliminary study started

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Calculation of Field error & 3D Perturbed Field for KSTAR

q=2/1

※ for vacuum (under calculation with response)

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Disruption Simulation for a new KSTAR Model pre-disrup. TQ CQ

KSTAR coil geometry & plasma boundary

Eddy current

(toroidal)

JT X Bp force

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Modeling of ELM Mitigation by RMP Method

- in collaboration with SciDAC team (CPES)

- Iterative 3D perturbed field calculation with plasma response using M3D, XGC0

- Plasma transport calculation using XGC0

Modeling of ELM Mitigation by Pellet Pace-making Method

- Initial study performed using ASTRA code with an approximate PPM model

- A more self-consistent modeling started using M3D code

Pedestal & ELM Control

Nonlinear simulation of ELM using BOUT++ code

- Recently started in collaboration with Dr. X. Xu in LLNL

- for a more detailed study of ELM itself and benchmark with M3D results

Modeling of NTV phenomena with 3D perturbed field

- in collaboration with Dr. K. Shaing in Taiwan

- both of analytic calculation and simulation study using XGC0 code

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• Modeling codes: XGC0 (kinetic transport), M3D (nonlinear MHD)• Numerical q95 scan (BT scan) for low collsionality DIII-D case reveals sensi-

tive magnetic stochasticity behavior around the experimental q95 ELM sup-pression window “Vacuum Chirikov is only a necessary condition”

• Current research focus Clarify effects of collisionality & density on ELM suppression mechanism Experimental validation in various tokamak RMP experiments including

KSTAR

Vacuum Chirikov is similar

Plasma-responded

Chirikov is different

3.623.52resonant win-

dow

Time (msec)

Simulation Study of RMP Control by RMP

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Simulation result for density distri-butionusing M3D code

Initial condition of a simulation for pellet injection

30 30 30 1010 10 10 1010

0 0 0 3030 10 10 1010

0 0 0 00 0 30 30 5

0 0 0 00 0 0 5 5

0 0 0 00 0 0 5 5

0 0 0 00 5 5 5 50 0 0 55 5 5 5 5

0

Pressure gradient, max

Cur

rent

dens

ity<j

//>m

ax.

3 3.5 4 4.5 50.6

0.7

0.8

0.9

1

1.1

1.2

1.3

6.5E-026.0E-025.5E-025.0E-024.5E-024.0E-023.5E-023.0E-022.5E-022.0E-021.5E-021.0E-025.0E-033.0E-032.6E-031.7E-031.0E-030.0E+00

edge pressure and current diagram for peeling-ballooning instability using ELITE code

The linear stability analysis using an ideal MHD stability code (ELITE)

Simulation Study of ELM & its Control by PPM

Nonlinear simulation study of ELM & its control by pellet pace-making method

(cf. talk by Dr. H.S. Hahn)

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Study of NTV with 3D Perturbed Magnetic Field

Substantial Analytic and Numerical Studies performed - As is well-known, symmetry breaking components in the magnetic field configuration increase

the viscosity in the toroidal direction (so called “Neoclassical Toroidal Viscosity”).

- In the last few years, significant studies on NTV performed and in each collisional regime the

theory has been established solidly.

- Recently, the general solution of NTV has been obtained by solving drift kinetic equation

(DKE)

numerically and the results are in good agreement with the analytic calculations.

A Particle Simulation Study planned - for a more exact study in a more general magnetic field configuration and comparison with the

analytic and DKE-based numerical results

- with EFIT EQDSK files and the actual 3D field component of KSTAR

- will use the codes XGC0 and (gKPSP1)

- in collaboration with G. Y. Park, K. Shaing (Taiwan) (cf. talk by Dr. J. C. Seol)

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ASTRA Simulation for Operation Scenario Modeling

- KSTAR operation scenarios in the 2nd operation phase (2013-2017)

- NTM control simulation with a self-consistent calculation of plasma evolution

※ in collaboration with SNU theory group (Prof. Y.S. Na)

NBI Heating & CD Simulation

- A more detailed study performed using NUBEAM for KSTAR NBI system model

Integrated Operation Scenario (with heating & CD)

ICRF Heating & CD Simulation

- Various ICRF heating scenarios for KSTAR, which include the minority-ion heating, mode-

conversion heating, 2nd harmonic heating etc.

- Flow generation from ICRF heating also being studied

Plan for Integrated Scenario Modeling

- trying to utilize the global gyrofluid code for a more self-consistent modeling of integrated

operation scenario, particularly considering turbulence evolution & pedestal formation

(cf. talk by Prof. Y.S. Na)

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Modeling of NBI Heating & CD• A detailed simulation performed of NBI heating & CD using NUBEAM code

- to support the optimization study of 2nd KSTAR NBI configuration

- comparison made of three possible NBI configurations

<For type A> <For type B2>

<For type B1>

Modeling of ICRF Heating & Flow Generation

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0 5 10 15 20 25 30-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

Hydrogen concentration [%]

toro

idal

forc

e at

(=1

) [N

]

/2-/2

0 5 10 15 20 25 30-0.01

-0.005

0

0.005

0.01

0.015

0.02

Hydrogen concentration [%]

toro

idal

forc

e at

(=1

) [N

]

/2-/2

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

nornalized minor radius

F(

) [N

]

0 = /2

1% H2% H5% H10% H20% H30% H

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-0.14

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

nornalized minor radius

F(

) [N

]

0 = /2

1% H2% H5% H10% H20% H30% H

Toroidal force Poloidal force

on last flux surface

• Momentum transfer from RFs, calculated using TORIC for minority ion heating case

ne=5×1019 m-3

(cf. talk by Dr. B.H. Park)

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Simulation Study of KSTAR Divertor/SOL Transport

- Initial study performed using UEDGE-DEGAS for KSTAR divertor design

- Also, a benchmark study performed using KTRAN(SNU-developed0 code in

collaboration with SNU group

- Recently, a more detailed study started using B2-EIRENE or SOLPS

Simulation Study of PWI

- Recently, ERO code imported from Julich group in Germany

- Simulation study to be started soon for the modeling of erosion, retention phenomena

Divertor Transport & PWI

Modeling of Charging and Transport of Dust Particle

- in collaboration with Prof. N.S. Yoon (Cung-Buk National Univ.) (cf. talk by Prof. N.S. Yoon)

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Simulation of KSTAR Divertor Transport

• Simulation results using KTRAN for KSTAR divertor model

Decrease of Impurity density, Increase of radiation

Max :1.5e18Max :8.69e18[m-3] [m-3]

[W/m2] [W/m2]

Impurity density

Power Radiation

TungstenCarbon

(cf. talk by Mr. S.B. Shim)

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Summary of Research Activities

Research area

Major research subjects Simulation codes Man power

Turbulent transport(WCI-project)

- Intrinsic rotation and momentum trans-port

- Transport barrier formation (ITB, ETB)- Non-local transport- Particle & impurity transport- Turbulence & MHD interaction etc.

- Global gyrofluid (TRB, BOUT++)- Global gyroki-netic (gKPSP, a new full-f)

5(+2+6)

*2: domestic collabora-tor*6 : for-eigner

MHD insta-bility

- Equilibrium & 3D perturbed field- Sawtooth, LM, NTM- Disruption- Energetic particle mode

- EFIT, MAFLO- NIMROD, 4-field- TSC- NOVA-K

2(+2)

Pedestal & ELM

- Pedestal stability (linear, non-linear)- ELM control by RMP- ELM control by PPM- NTV & neoclassical transport

- BOUT++- XGC0+M3D- M3D- XGC0

3(+1)

Integrated Scenario

- KSTAR operation scenarios- Heating & CD modeling (NBI, ICRF,

LHCD, ECH/ECCD)

- ASTRA- NUBEAM, TORIC, LSC, TORAY

2(+1)

Divertor & PWI

- KSTAR divertor transport- PWI (erosion, retention)- Dust*

- B2-EIRENE(SOLPS)

- ERO- (Prof. N.S. Yoon)

1(+1)