Progress of the Integrated Plasma Control Working Group

1. Progress of the Integrated Plasma Control Working Group J A Snipes ITER Organization

2. ITPA Integrated Plasma Control Working Group • Mandate: The ITPA IPCWG will determine the physics requirements of the actuators and diagnostics of the ITER Plasma Control System (PCS) to permit the PCS to carry out its control functions and to meet the goals of the ITER reference scenarios • Deliverable: Produce a document for input to the PCS design describing the physics requirements of the PCS actuators and diagnostics at the conceptual design level sufficient to show their feasibility to perform the PCS functions • Timescale: Preliminary report now, intermediate report at the April 2012 IOS meeting, followed by a final report at the October 2012 IOS meeting to be in time for the PCS CDR in November 2012 • Control Area Leaders:T Casper – Pressure Profile, D Humphreys – Actuator Sharing, A Kallenbach – Divertor Heat Flux, R La Haye - NTM, T Luce – Temperature Profile, D Mazon – Current Density Profile,R Pitts – First Wall Heat Flux, A Polevoi – Fueling and Impurity, J A Snipes – ELM, T Tala - Rotation, D Testa – Alfvén Eigenmode Control

3. Integrated Plasma Control Working Group Activities • The ITPA IPCWG should provide physics input to quantify the ITER PCS requirements for actuators in time for the PCS CDR • This work should complement the work being done in the Plasma Control Group IPT and in the MHD ITPA Working Groups • WG3: “Power requirements for ECRH & ICRF control of sawteeth” • WG4 on “Diagnostic requirements for MHD stability control” • The IPCWG should assess the realistic feasibility of the PCS to carry out its control functions across a range of ITER scenarios • early non-active scenarios in H/He at half and full current & field • 15 MA, 5.3 T Q=10 inductive scenarios • 10 – 13 MA, 5.3 T Q > 5 long pulse (1000 s) Hybrid scenarios • 8 – 9 MA, 5.3 T Q~5 steady-state (3000 s) scenarios

4. What is Meant by Realistic Feasibility? • The IPCWG should take into account the actual constraints of the ITER diagnostics and actuators that will put real limits on the control actions of the PCS • Through modeling and comparison with present experiments then determine how much those real diagnostic and actuator limitations are likely to affect the PCS control functions, such as • NB RID thermal fatigue limits power modulation for burn control • EC steering mirror full sweep takes 3 s + ~0.2 s to respond to PCS • The level of detail required depends on the impact a given constraint is likely to have and the amount of work required to assess it given the short timescale available before the CDR • For the CDR, only the control concept must be shown to be feasible not the detailed implementation nor the algorithms

5. MHD WG4 Already Did Much of the Diagnostics Task • The work was broken down into eight MHD stability or control method areas: • • Stabilisation of the Vertical instability • • Stabilisation of the Resistive Wall Mode (RWM) instability • • Stabilisation of the Neoclassical Tearing Mode (NTM) instability • • Stabilisation or modification of the Sawtooth instability • • Stabilisation or modification of the Edge Localised Mode (ELM) instability • • Control or modification of of the Alfvén Eigenmode (AE) instabilities • • Control of the error fields leading to enhancement of instabilities • • Control, prediction, avoidance or mitigation of plasma disruptive instability • Leaders, Contributors and Reviewers were nominated for each topic • The Leaders drove the process for each topic, with assistance from the Contributors • The Reviewers reviewed the findings of the Leaders and Contributors • An Excel spreadsheet template was used to summarise the quantifiable requirements and any unquantifiable requirements for each topic

6. Example of MHD WG4 Diagnostic Requirements Stabilisation of the Neoclassical Tearing Mode (NTM) instability

7. Integrated Plasma Control Working Group Progress • The IPCWG is assessing the physics requirements of the ITER PCS actuators in a similar set of spreadsheets for actuators • In addition, the IPCWG should assess diagnostic requirements in all other control areas outside MHD control as well as for runaway electron control and mitigation • First draft spreadsheets have been produced in all of the control areas initially proposed

8. Fuelling and Impurity Control – 1: Pellets

9. Fuelling and Impurity Control – 2: Gas

10. Divertor Heat Flux and Radiation Control

11. Rotation Profile Control

12. Current Density Profile Control

13. Temperature Profile Control

14. Pressure Profile Control

15. ELM Control

16. NTM Control

17. Alfvén Eigenmode Control

18. Shared Actuators: Leader – Dave Humphreys

19. What Should the Final IPCWG Document Contain? • The document produced by the IPCWG should state what are the minimum actuator and diagnostic requirements that are necessary for the PCS to control ITER plasmas for the non-active, inductive, Hybrid, and steady-state DT scenarios concentrating particularly on H&CD profile control, fueling, and impurity control • It should also compare those necessary requirements with actuator and diagnostic requirements and limitations as specified in the ITER baseline documents (Project Requirements, SRD’s, etc) • It should point out any discrepancies that are likely to compromise any of the PCS control functions for any of these scenarios • Suggestions should then be proposed that could either recover the PCS control function in question or propose an R&D plan to try to find a way to resolve the issue

20. IAEA Technical Meeting on Plasma Control • Paper presented on Actuator and Diagnostic Requirements of the ITER PCS at the IAEA TM on Plasma Control, June 2011 • Submitted for publication to Fusion Engineering and Design • This paper covered the main actuator and diagnostic requirements of the PCS that have been studied to date including: • Magnetic control requirements • Specific limitations of the H&CD and fueling and pumping systems • A summary of the MHD control diagnostic requirements assessed by the MHD ITPA WG4 • A summary of the WG3 sawtooth control requirements

21. Need to Include all Control Areas • The PCS CDR must cover all control areas expected for ITER operation in inductive, Hybrid, and steady-state scenarios • To complete the PCS control areas, additional leaders have been nominated for the remaining PCS control topics: • Anyone else who would also like to contribute to this effort in any control areas, please send me their name and area