1 / 18

Some Considerations on diagnostics for ITER LH antenna

O Tudisco ENEA. Some Considerations on diagnostics for ITER LH antenna. Introduction. After Annika talk at the last meeting (3/3/2009), some points were still open : Reflectometry In addition to Langmuir probes, reflectometry can be used to measure the electron density.

shiela
Download Presentation

Some Considerations on diagnostics for ITER LH antenna

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. O Tudisco ENEA Some Considerations on diagnostics for ITER LH antenna

  2. ENEA-CEA meeting Introduction After Annika talk at the last meeting (3/3/2009), some points were still open : Reflectometry In addition to Langmuir probes, reflectometry can be used to measure the electron density. Window arc detection Need to verify if, and which, optical fibres can be used in this environment, close to the support structure. Visible spectroscopy A visible spectroscopy system, with a few lines-of-sight viewing the launcher front face, is considered a more efficient and rapid system to detect arcs in front of the launcher. Need to find if a suitable port space, that allows viewing the front face of the launcher, and need to design the system

  3. ENEA-CEA meeting summary Reflectometer Standard reflectometer for ITER Reflectometer for ICRH antenna (F. Clairet)‏ Study of the reflectometer for LH frequency and antenna size Visible spectroscopy Collecting optics of the MSE Collecting optics of the visible and IR camera for ITER Arcs detections RF reflectometer in LH waveguide (R. Maggiora)‏

  4. ENEA-CEA meeting reflectometry Due to the large thermal load Langmuir Probes CANNOT be inserted in ITER SOL. Reflectometer is mandatory for the measurement of the density before the antenna mouth

  5. ENEA-CEA meeting Main ITER reflectometers Many systems are foreseen in ITER for the reflectometry. (G. Vayakis et al, N.F. 2006, G. Vayakis et al, RSI 1997) Plasma core is only accessible from the HFS. Special antenna has been designed Edge is accessible from the LFS. Very oversized corrugated circular waveguides will be used.

  6. ENEA-CEA meeting HFS antenna for reflectometry 23´12.5 mm Vayakis, NF 2006

  7. LFS antenna for reflectometry Ø 89.5 mm D. Johnson 2006 Vayakis, NF 2006 ENEA-CEA meeting

  8. Reflectometer antenna for ICRH 22 30 mm from R. Koch ENEA-CEA meeting

  9. ENEA-CEA meeting Reflectometry for LH : density range • Density : • from 6´1017 m-3 • to 2.5´1019 m-3 • O-mode • from 7 GHz • to 45 GHz • X-mode L (BT = 4T)‏ • from 0.4 GHz • to 16 GHz • X-mode R (BT = 4T)‏ • from 112 GHz (Ne=0)‏ • to 128 GHz

  10. ENEA-CEA meeting Reflectometry for LH: Principle The phase measured by the reflectometer is in order to invert this formula the full density profile (from antenna to cut-off) is needed. The Inversion is where K(w) depends on the refractive index

  11. ENEA-CEA meeting reflectometry for LH : sensitivity O-Mode XR-Mode 250 800 F (rad)‏ F (rad)‏ 0 0 5 112 freq (GHz)‏ 45 freq (GHz)‏ 128 40 180 dF/dw (rad/GHz)‏ dF/dw (rad/GHz)‏ 20 20 0 5 112 5 45 128 freq (GHz)‏ freq (GHz)‏

  12. ENEA-CEA meeting reflectometry for LH : waveguide (X-mode)‏ use a slightly oversize waveguide (WR-15)‏ size(6x4.5 mm) horns (20 dB) (size 21x16, L=36 mm) high attenuation (~3 dB/ m) do not need alignment use a very oversized corrugated waveguide size (30-50 mm) mitre bent no horns. low attenuation alignment problems

  13. Visible spectroscopy and arc detections ENEA-CEA meeting

  14. ENEA-CEA meeting Collecting optics for MSE Vacuum Window Metallic Mirrors Fiber only outside the Vacuum Vessel

  15. ENEA-CEA meeting collecting optics of visible&IR camera Dielectric components far from the machine Vacuum Window JM Travere

  16. ENEA-CEA meeting Spectroscopy for LH. An optical collecting system with metallic mirrors is needed to relay the light far from the vacuum vessel. No dielectric components (fibers, lens, etc..) are advisable to be put inside the port. The standard Vis&IR inspection foreseen 24 cameras to cover 80% of ITER vacuum vessel. (3 cameras per port-plug)‏ Is it possible to share one of this camera with LH spectroscopy?

  17. ENEA-CEA meeting Share light with the camera. fiber bundles Power splitter

  18. ENEA-CEA meeting conclusions Reflectometry in X-mode Right cut-off can be suitable for density measurement before the LH antenna Slight oversized waveguide is a good compromise between losses and alignment problems. An optical collecting system similar to that of the vis&IR camera must be used for the inspection of the antenna front-end Arc detection through fibers can be problematic.

More Related