Advanced Simulations for the ITER LH Launcher

1. Advanced Simulations for the ITER LH Launcher D. Milanesio, R. Maggiora

2. TOPLHA Modeling – Reference Geometry Ia • Single PAM module • 8 active waveguides (in dark color) • 9 passive waveguides (in light color) • Main dimensions reported in the zoomed view • Passive waveguides are short-circuited after λg/4 • Flat geometry

3. TOPLHA Modeling – Reference Geometry Ib • Poloidal curvature added to the flat geometry 2 mm

4. 3 mm TOPLHA Modeling – Reference Geometry Ic • Both poloidal and toroidal curvature added to the flat geometry 2 mm

5. HFSS scattering matrix has been adopted to account for the PAM module The return loss is plotted at the generator side of a PAM module λ = densityedge/Δdensity TOPLHA Results – Return Loss (Ref.Geo. Ia)

6. HFSS scattering matrix has been adopted to account for the PAM module The return loss is plotted at the generator side of a PAM module λ = 2 mm TOPLHA Results – Return Loss (Ref.Geo. Ia/b/c)

7. All active waveguides have been fed with 270° phase increment TOPLHA Results: Power Spectra (Ref.Geo. Ia) Power spectra are computed assuming the entire antenna delivers 20MW of power

8. TOPLHA Results: Current & Fields (Ref.Geo. Ia) @ cutoff density λ = 2 mm

9. An arc is modeled as a metal strip connecting the two sides of the waveguide “aperture” TOPLHA Modeling – Reference Geometry II • Single PAM module • 8 active waveguides (in dark color) • 9 passive waveguides (in light color) • Few active waveguides are short-circuited at the mouth to mimic an arc (in blue) • Passive waveguides are short-circuited after λg/4 • Flat geometry

10. HFSS scattering matrix has been adopted to account for the PAM module The return loss is plotted at the generator side of a PAM module λ = 2 mm TOPLHA Results – Return Loss (Ref.Geo. II)

11. TOPLHA Results: Current & Fields (Ref.Geo. II)

12. TOPLHA Modeling – Reference Geometry III • Three PAM modules • 24 active waveguides (in dark color) • 25 passive waveguides (in light color) • Main dimensions reported in the zoomed view • Passive waveguides are short-circuited after λg/4 • Flat geometry

13. HFSS scattering matrix has been adopted to account for the PAM module The return loss is plotted at the generator side of a PAM module λ=densityedge/Δdensity An extensive comparison between TOPLHA and ALOHA can be found in J.Hillairet’s presentation TOPLHA Results – Return Loss (Ref.Geo. III)

14. Next Steps • Optimization of the front part of the launcher • Extension to the full antenna

15. On Electric Fields Interpolated output (done by Gid) Vs. Standard TOPLHA output The magnetic current value is computed on the mid-point of central edges (exact values); then, each triangle is colored according to the sum of the RWG functions defined on it

16. On Electric Fields • The difference between ALOHA and TOPLHA in terms of maximum Epar increases with the density • This difference can se significantly reduced: • Adopting the real TOPLHA output instead of the interpolated one • Increasing the number of functions on the aperture