Plasma Operations: General Introduction

1. Plasma Operations: General Introduction Peter Lomas and Plasma Operations Group:- Jerzy Brzozowski, Peter de Vries, (Marco de Baar), Robert Felton, (Emmanuel Joffrin), Isabel Nunes, Fabio Piccolo, Filippe Sartori, Luca Zabeo Plasma Operations : Introduction P.J.Lomas

2. Contents Grad Shafranov equation Poloidal coils and power supplies Plasma Control Plasma Equilibria, Proteus, Maxfea, EFIT The Standard equilibria, The Pulse Schedule The control of Toroidal Field Gas fuelling Reprise Plasma Operations Introduction P.J.Lomas

3. The Grad Shafranov Equation Force Balance Poloidal magnetic flux function, Poloidal current flux function, Together with Amperes Law gives Unit vector toroidal direction Key toPlasma Engineering and Tokamak data interpretation See e.g John Wesson, Tokamaks, 2nd ed. Oxford Science Publications Plasma Operations Introduction P.J.Lomas

4. For a theorist The JET coils and iron are just the boundary conditions for solving the equation For a Plasma Engineer The Grad Shafranov equation is just a tool which helps us exploit the power of JET machine for producing the plasmas we want, shape and position. Coils, or parts of coils are arranged in circuits with the various power supplies and these are controlled by the Plasma Position and Current Control system PPCC Plasma Operations Introduction P.J.Lomas

5.  + + P4 Imbalance Circuit PVFA4 - - - + + PVFA2 PFX D1 PVFA3 D4 - D2 D3 P4 Circuit Shaping Circuit P1 External Circuit PFX Circuit + + PVFA1 - - PFGC Poloidal Field Circuits and Power Supplies + 4 Poloidal Divertor Circuits The functions of the individual circuits will be described in Plasma Ops I Plasma Operations Introduction P.J.Lomas

6. TheseCircuits are controlled byShape ControllerPPCC-SCusing themagnetic measurementsand real timeboundary reconstruction Magnetic Diagnostics 9 PF Amplifiers 9  IPF Ip Zp Rp I V Protection XLOC IPF Calculate 9 PF Voltages PPCC Decoupling other parameters SL waveforms See lecture Plasma Control by Fernanda Rimini Plasma Operations Introduction P.J.Lomas

7. Grad Shafranov Solvers, Plasma Equilibrium Design Control and Reconstruction Design Control Reconstruction PROTEUS EFIT XLOC Physics, Mapping MAXFEA Plasma Operations Introduction P.J.Lomas

8. There are >69 commonly used equilibria (standard scenarios) E.g Triangularity scan V/SFE/LT V/SFE/HT V/SFE/VHT V/SFE/EHT ITER-LIKE Triangularity variation 0.15-0.50 See Plasma Ops II Plasma Operations Introduction P.J.Lomas

9. Often modifications are required:- Adjust top gap Move outer strike Done by editing GAP waveforms, see Plasma Control Plasma Operations Introduction P.J.Lomas

10. A particular session might require a number of different pulses, PULSE-TYPES. These are prepared (in advance) to make up a PULSE-SCHEDULE using the Pulse Schedule Editor XPSEDIT. This tool gives the Session Leader control over Toroidal Field Poloidal Field Gas Real Time Control You will hear a lot more about this over the week Plasma Operations Introduction P.J.Lomas

11. For example the large and complex power supplies driving the toroidal field can be driven from a single wave-form in the Pulse-Schedule Editor. This high level control is called LEVEL 1. Plasma Operations Introduction P.J.Lomas

12. The JET gas introduction is another complex system:- 10 Gas Introduction Modules (GIMs) and one Tritium module. The plasma density needs to be processed, validated and routed the the Density Feedback and Valve controllers. SL density waveform RealTimeCentral Controller PID interferometer process Real Time Signal Server bremsstrahlung GIM GIM waveform Dedicated pages in the pulse schedule, see Rob Felton’s talk Plasma Operations Introduction P.J.Lomas

13. This lecture is a very brief intoduction to:- Grad Shafranov equation Poloidal coils Plasma Control Protection Plasma Equilibria, Proteus, Maxfea, EFIT The Standard equilibria, The Pulse Schedule The control of Toroidal Field Gas fuelling You should now begin to understand how a JET pulse is put together. Any questions? Plasma Operations Introduction P.J.Lomas