Integrated Modelling of ICRH and AE Dynamics

1. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain Integrated Modelling of ICRH and AE Dynamics T. Hellsten, T. Bergkvist, T. Johnson and M. Laxåback Alfvén Laboratory, Royal Inst. of Technology, SE-100 44 Stockholm, Sweden Association Euratom-VR.

2. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain ICRH is a versatile heating method that can provide: Heating Enhance fusion reactivity Drive Currents Induce rotation Excite AEs

3. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain ICRH requires self-consistent modelling of distribution functions and wave field; including effects of finite orbit width and RF-induced spatial transport of fast ions for waves with finite nf. Due to the different time scales this can be done by iterations.

4. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain

5. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain -90o phasing: trapped 3He ions displaced outwards.? emission from turning points of trapped ions at cyclotron resonance

6. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain Comparison of the gamma emissitivity in the mid-plane z=0 between tomographic reconstructions (full line) dashed region (confidence interval) and the density of high-energy 3He ions calculated with the SELFO code (boxes)

7. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain 

8. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain Splitting of the mode frequency

9. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain Ion interaction with AEs In the absence of Coulomb collisions and ICRH the interactions of a resonant ion with an AE lead to a superadiabatic oscillation in the phase space of the invariants of the equation of motion for the drift orbit along the AE characteristics

10. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain Decorrelation of the interactions leads to a diffusion of the orbits along the characteristics instead of a superadiabatic oscillation. Ion cyclotron interactions and Coulomb collisions will partially restore the distribution function in the resonant regions and result in further transfer of energy from the resonant ions to AEs. The decorrelation of the interactions and local renewal of the distribution function by ICRH increases with energy, whereas they decrease with energy for Coulomb collisions.

11. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain Renewal of the distribution function by ICRH

12. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain

13. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain 

14. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain TAE Resonance regions

15. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain The dynamics of TAE and frequency splitting

16. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain Mode damping after ICRH switch off

17. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain Conclusions Self-consistent computations of wave field and distribution function are important for ICRH, in particular for power partition. The effects of finite orbit width and RF-induced spatial transport are important for many phenomena. The dynamics of the AEs are strongly affected by ICRH, which have to be taken into account when simulating AE excitation by thermonuclear alpha particles using ICRH ions. The decorrelation by ICRH increases the width of the resonances and the renewal rate, making the interactions with AE much stronger.

18. T. Hellsten IEA Burning Plasma Workshop, July 2005 Tarragona Spain Code for self-consistent modelling of heating