T. A. Casper, D. Campbell, Y. Gribov, S.H. Kim*,
T. Oikawa, A. Polevoi, J.A. Snipes, A. Winter, and L. Zabeo
ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance, France
* Monaco post doctoral program at ITER
Acknowledgement: CORSICA support
R. Bulmer, L.L. LoDestro, W.H. Meyer, and L.D. Pearlstein,
Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA USA 94550
ITPA IOS Meeting
October 18 – 21, 2011
Kyoto, Japan
T.A. Casper, ITPA IOS Kyoto Japan
1

Modeling development for ITER scenarios: 1D transport + 2D equilibrium only (does not include other modeling work at ITER)

Scenario development that requires lots of parameter variation studies can and often is done with prescribed boundary evolution

Controller development and evaluation of engineering constraints require free-boundary with coupling to external systems
 Scenarios of interest:
 Full field scenarios at B
T
=5.3T in H-mode:

Baseline inductive: I
P
=15MA, Q=10, P fus
=500MW, to 400s duration

Advanced inductive or hybrid: I
P
=12.5MA, Q=5, 1000s duration

Steady-state: I
P
=9MA, Q=5, steady state – likely internal transport barrier
 Low-activation scenarios:

DD at I
P
=7.5MA and B
T
=2.65T (half I
P
, B
T
)

Under development and of current interest for early experiments
 Non-activation scenarios: H or He operations at reduced I
P
, B
T
 New interest for modeling to minimize CS coil demands

MHD evaluation for scenarios
T.A. Casper, ITPA IOS Kyoto Japan
2

Approaches leading to development of ITER scenarios

Internal at the IO

To develop internal ideas quickly and to test concepts

Build on and supplement work done outside the IO

Rapid response to committees and engineering design crises

Provide data to external research efforts, e.g. equilibria, profiles, constraints, etc.
 Funded ITER tasks

Major efforts to scope out scenarios and/or design modifications – longer term

Contracts and must be competed among the DAs, a somewhat slow process
 Volunteer – many efforts in DA programs typically coordinated by ITPA

Benchmarking with experimental data

Model and code validation

Modeling scenarios and detailed physics aspects – a few recent examples:

ISM coordinated effort in EU (Litaudon) – several codes and variety of topics

Individual efforts in scenarios with both DINA(Russia) and TSC(US)

Data sent for many physics studies: BOUT and ELITE edge stability, MHD evaluation,
ECH study, RMP study, first wall evaluation, runaways, ripple loss, etc. etc. etc.
T.A. Casper, ITPA IOS Kyoto Japan
3

Recent ITER tasks and internal studies have advanced understanding of likely ITER performance: mostly CORSICA, DINA, and TSC

Current modeling includes latest modifications to ITER systems
 coil and first wall geometry (may change again)
 power systems and source design parameters

Increasing awareness of the divertor and first wall

Baseline inductive modeling – successful scenarios within operating space

Kessel, C.E.
et al Nucl. Fusion 49 (2009) 085034

Casper, T. et al accepted Nuc. Fusion 51 (2011) ; in Fusion Energy 2010 (Proc.
23rd Int. Conf. Daejeon, 2010) (Vienna: IAEA) CD-ROM file ITR/P1-19 http://www-naweb.iaea.org/napc/physics/FEC/FEC2010/html/index.htm

ITER tasks and efforts at the IO advanced modes: advanced inductive (hybrid) and steady-state scenarios (Gormezano, C. et al Nucl. Fusion 47 (2007) S285-S336)

Kessel, C.E. et al in Fusion Energy 2010 (Proc. 23rd Int. Conf. Daejeon, 2010)
(Vienna: IAEA) CD-ROM file ITR/P1-22 and http://wwwnaweb.iaea.org/napc/physics/FEC/FEC2010/html/index.htm

EU/F4E modeling effort currently in progress – results later today?

IO modeling effort started for hybrid mode: Sun Hee Kim presentation
T.A. Casper, ITPA IOS Kyoto Japan
4

Voluntary efforts have contributed significantly to ITER scenario development understanding – for example, a recent STAC report:
CRONOS: J. Citrin et al., Nucl. Fusion 50
115007 (2010).
TOPICS-1B: N. Hayashi et al., Final Report on the
ITER Task Agreement
C19TD26FJ
ITER_D_48DP5Z, 24
February 2011.
Code-code comparison for steady-state scenarios
Murakami, M. et al. Nucl.
Fus. 51 103006 (2011).
T.A. Casper, ITPA IOS Kyoto Japan
5

CORSICA: Current emphasis for modeling at the IO is control of scenarios and development of the plasma control system (PCS)
 2D equilibrium + 1D transport predictive modeling code provides capability for controller simulations - applied to shape, vertical stability and profile control
Crotinger, J.A. et al LLNL Report UCRL-ID-126284,1997 NTIS #PB2005-102154
 Full free-boundary GS solutions with various transport models - control of the evolution of plasma shape, vertical position and kinetic profiles

Simultaneously converges free-boundary equilibrium with transport at each time step – solutions always self-consistent

Calculates sources each time step - needed for feedback control applications
 Monte-Carlo NBI with orbits and Toray-GA ECH/ECCD – previously used for DIII-
D modeling and updated for ITER by Sun Hee Kim

ICH and LH capability recently added by Sun Hee Kim
 DCON for time-dependent MHD stability assessment
 Coupled with simulink control environment - independently executing and connected with RPCs (Meyer, W. et al , IAEA-TM, San Francisco June 2011)

Modular, customizable with interruptable work flows from interpretive scripting language interface – flexible and extensible environment
T.A. Casper, ITPA IOS Kyoto Japan
6

Elements in place at ITER for a PCS simulator: ITER control methods, JCT2001 controller, CORSICA implementation
(b) Corsica realization of control simulator
Casper, T.A. et al, FED 83 (2008) 552-556
(c) ITER shape and vertical position control
(d) JCT2001 controller
T.A. Casper, ITPA IOS Kyoto Japan
7

CORSICA (or any code, e.g. DINA, TSC) free-boundary capabilities are required for controller modeling and development
 CORSICA modes of operation (Casper, T.A. et al, FED 83 (2008) 552-556)
 “backing-out”: fast, prescribed boundary evolution (no controller) with freeboundary evaluation at each time step to couple to external systems

Fast scenario development

Most engineering constraints evaluated, e.g. currents, forces, limits

Provides feed-forward waveforms for forward control
 “forward” : full free-boundary shape and vertical stability evolution with controller – must run with dt ~ vertical growth time so lots of time-steps required
 “hybrid”: free-boundary shape from controller in simulink with vertical stability internal to CORSICA – a new development done for speed in long pulse control simulations
 Coupling to simulink provides a mechanism to test controllers (shape, vertical stability, and profile) during development

JTC2001 controller +VS1,VS3 both in simulink and internal to CORSICA

Interpretive interface with interrupts provides a mechanism for simulating event handling
T.A. Casper, ITPA IOS Kyoto Japan
8

CORSICA feedback-controlled evolution for baseline inductive case: I
P
=15MA, Q=10, 400s duration burn and P fus
=500MW

JCT-2001+VS1 controlled shape and vertical position, typically
~15,000 converged free-boundary solutions (700s discharge)

Performance results (a)
 Coil currents (b,c) and forces (g) within operational limits
 Controller voltage demands for vertical stability (d) and shape (e,f)
(g)
T.A. Casper, ITPA IOS Kyoto Japan
9

Time-dependent evaluation (B,I)-limits and forces on coils
* Simulation from fast current ramp with 17% reduction in I*B ~ different initial magnetization state
* Power ramp to control power to divertor
New diagnostic:
UFC = utilization factor for superconducting coils – moved from equilibrium design to time-dependent
T.A. Casper, ITPA IOS Kyoto Japan
10

Summary/Future: the tools are in place and we are simulating a variety of controller aspects for ITER

Controller development - simulations will support these efforts
 New controllers have been proposed for improving ITER performance
 The Plasma Control System (PCS) conceptual design in progress Shape and vertical position

Significant efforts have been done for the baseline 15MA case
 This needs to be extended to the alternative scenarios

Advanced inductive (hybrid) is being worked on

The Steady-state control will be done

Non- and low-activation scenario are being defined and developed
 Kinetic control efforts for performance

Feed-back control of q (current profile)

Temperature and stored energy control

Burn control
 Stabilization of islands

Event simulation, database and display testing
T.A. Casper, ITPA IOS Kyoto Japan
11

Additional concerns/emphasis for scenario modeling with regards to experiments

More experimental validation of codes used for ITER scenario analysis
 Lots has been done to date, keep going
 Concepts that need to be integrated into scenarios, e.g. divertor and stability

Effort to benchmark profile control between simulations and experiments

Specific studies of current ramp-up/ ramp-down scenarios under ITERrelevant conditions (i.e. potentially with a tungsten divertor)

Compatibility with tungsten divertor

Now using power ramp (5-20MW) during current ramp

Characterization of MHD during the current ramp-up in X-pointconfigurations

Fast, heated current ramp-up after X-point formation

Stability boundary lurking somewhere

Non-activation or low activation DD scenarios

I
P
/2 and B
T
/2 with ECH

Full B
T at reduced I
P
~ 10 or 12MA
 CS coil limitations for “reduced” operation
T.A. Casper, ITPA IOS Kyoto Japan
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