1. L. Zanotto – 10 February 2011 – RFX-mod programme workshop TF2: Active control of RFP and tokamak plasmas Report on experimental proposals L. Zanotto, P. Piovesan, A. Soppelsa

2. L. Zanotto – 10 February 2011 – RFX-mod programme workshop Main areas covered by proposals  Tokamak scenarios  3D magnetic field effects on flow  RWM in RFP  m=0 control and understanding  Active control of RFP plasmas  Optimisation

3. L. Zanotto – 10 February 2011 – RFX-mod programme workshop Main areas covered by proposals

4. L. Zanotto – 10 February 2011 – RFX-mod programme workshop Tokamak scenarios  Scenario development o H-mode (from DIIID) o Density limit o New states (helical boundaries) o Additional heating (DNBI)  Active control of Tokamak discharges o Active rotation o Sidebands studies o RWM control o Control of m=2, n=1 and error fields o Pellet injection and MHD control o RFA studies  Comparison between RFX-mod Tokamak and RFP discharges o Tokamak H-mode vs RFP high edge temperature gradient plasmas o Spontaneous rotation  Flow in Tokamaks o Effects of magnetic field perturbation on flow profile o RMP effects on zonal flows and edge

5. L. Zanotto – 10 February 2011 – RFX-mod programme workshop 3D effects on flow in RFPs  Effect of the 1/-7 flow on the penetration of magnetic field errors  External magnetic perturbation effect on plasma flow (T2R team)  comparison with T2R results

6. L. Zanotto – 10 February 2011 – RFX-mod programme workshop Resistive Wall Modes in RFP  Model validation experiments o Expand the benchmark of existing and new numerical models  Test of innovative control schemes o Reconfigured sensor system o Resilience to magnetic noise and disturbances  RWM in high current helical plasmas

7. L. Zanotto – 10 February 2011 – RFX-mod programme workshop m=0 control and understanding  Control of m=0 by means of saddle coils o Imposing m=0, n=7 (n = 14) harmonic to vary the island amplitude and study PWI o High gains for m=0, n<7 @ F<=-0.1 o Study of the toroidal field ripple by imposing stationary m=0, n=12,16, 24  Development of new feedback control scheme for low order m=0 harmonics o Can benefit from optimisation experiments on toroidal power supply  Study of toroidal field ripple o Imposing stationary m=0, n=12,16, 24 o Excluding some toroidal field coils

8. L. Zanotto – 10 February 2011 – RFX-mod programme workshop Optimisation  Power supplies o Optimisation of toroidal inverter gains o Voltage control of TFAT converters o Enhancement of toroidal power supply control  Upgrade of the Plasma Current Control System o Optimisation of the feedback regulator o Implementation of automatic plasma current ramp-up o Improve controller awarness of machine operative conditions  Correction of local toroidal field measurement o Slight misalignment due to mechanical tolerance  pick-up of poloidal field o Can provide a reduction of the heating observed at the same two toroidal position

9. L. Zanotto – 10 February 2011 – RFX-mod programme workshop Active control of RFP plasmas  Innovative schemes and advanced concepts o Modal Dynamic Decoupler o System Identification (T2R proposal) o Independent B  and B r feedback o Feedback on plasma response o Control of the m=1, n=-7 at the resonance  Active control o DRE pacing o Different toroidal flux conserving boundaries o Test of a different decoupling matrix o 3D boundary conditions at high plasma current o Study of plasma-shell proximity effect

10. L. Zanotto – 10 February 2011 – RFX-mod programme workshop Main constraints to be considered  Many proposals involve Tokamaks  Need to develop a reliable scenario (not an easy task with X-point)  Check feasibility of single null X-point configurations (asap)  Check availability of diagnostics and/or additional heating (DNBI, NBI)  New control hardware and software architecture is being developed (see A. Barbalace’s talk)  Integration and interaction with the experimental programme must be assessed as soon as possible  An experimental proposal clearly stating the plan for integration is needed  Ready this year?  Some proposals require work/modifications to be carried out on the control system and on the power supplies  Collaboration between TF2 and Operation Support will be essential  Availability of proposers external to the laboratory  Various constraints to be considered

11. L. Zanotto – 10 February 2011 – RFX-mod programme workshop Experimental programme Shut-down aprile commissioning Commissioning GDC Restart RFP plasma Restart TOK plasma GDC Test TOK with SN X-point First TF2 experiments will be devoted to tokamak. The aim is only to test present capabilities after a long time without tokamak discharges. Operation Support to check technical feasibility of SN X-point.

12. L. Zanotto – 10 February 2011 – RFX-mod programme workshop TF2 commitments for 2011  Tokamak operation  Re-establish reliable operation to be able to perform proposals on active control, flow and edge studies  Try to develop the H-mode scenario  Improve tools for control and understanding of m=0 modes  Optimisation toroidal power supply  Implementation of a new m=0 controller  Integration of the new control system architecture  Major issue  Test innovative control and identification concepts  Modal Decoupler and/or others

13. L. Zanotto – 10 February 2011 – RFX-mod programme workshop Missing  Proposals taking advantage from the new control system  Optimisation and setup of diagnostics  Proposals dealing with plasma shape  Comparison with MST (maybe in TF1?)

14. L. Zanotto – 10 February 2011 – RFX-mod programme workshop Discussion  Is there any other area not covered by proposals?  Integration of the new control system: we should really identify when we want the new system to be in operation  the availability of the new system may lead to a substantial revision of the proposals (  overall re-optimisation of the control gains is probably necessary)  a clear path to the new system should be established now  Do we have enough tools to develop H-mode in RFX-mod tokamaks? It is not simply a matter of producing a Single-Null X-point in vacuum… Experience is needed directly in the control room.