1 / 16

Status of EBW Emission Analysis on NSTX

Status of EBW Emission Analysis on NSTX. S.J. Diem July 20th, 2006. XP 625: B-X-O Mode Conversion Physics at 8-40 GHz. Study 8-40 GHz thermal EBW emission via oblique B-X-O coupling Use remotely-steered, quad-ridge antennas and dual-channel radiometry at Bay G

lewis-whitehead
Download Presentation

Status of EBW Emission Analysis on NSTX

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. Status of EBW Emission Analysis on NSTX S.J. Diem July 20th, 2006

  2. XP 625: B-X-O Mode Conversion Physics at 8-40 GHz • Study 8-40 GHz thermal EBW emission via oblique B-X-O coupling • Use remotely-steered, quad-ridge antennas and dual-channel radiometry at Bay G • Study behavior of EBWs emitted from the fundamental, 2nd and 3rd harmonic emission from L-mode and H-mode plasmas • Experiment had three objectives: • Map coupling efficiency as a function of antenna pointing direction and compare to theory • Analyze emission polarization and compare to theory • Measure Te(R,t) using thermal EBW emission

  3. Upgraded EBW antennas allow spatial mapping of emission window • Fundamental (8-18 GHz) • 2nd and 3rd harmonic (18-40 GHz) AORSA-1D NSTX  = 40% Bt(0) = 3.5 kG f = 28 GHz M. Carter ORNL • Motors allow for ±10 degrees of motion in poloidal and toroidal directions • Fundamental beam waist radius ~ 11° at plasma edge • Harmonics beam waist radius ~ 7 ° at plasma edge Beam waist >90%

  4. Strong fundamental emission observed during L-mode scan Fundamental emission • 800 kA plasma • Te(0)~1.6 keV • Window losses not included Reflectometer signal

  5. L-mode harmonic emission lower than fundamental Reflectometer signal

  6. Spatial scan provides good coverage of emission windows *Window losses not included in mode conversion efficiency calculation

  7. L-mode polarization measurements • Polarization of maximum emission ~1.7 • Polarization varied from 1.25-1.7

  8. Te(R) profile from emission data Thomson data 1.1 600 Ray damping location from GENRAY 500 1.05 Radius [m] 400 Te [eV] 1.0 300 Te (R) from EBW 200 0.95 95 100 105 110 Radius [cm] 12 13 14 15 16 Frequency [GHz]

  9. H-mode emission much lower than L-mode Fundamental emission • 1 MA plasma • Te(0)~1 keV • Window losses not included Reflectometer signal

  10. Very low harmonic H-mode emission observed

  11. H-mode spatial scan provides coverage of emission window *Window losses not included in mode conversion efficiency calculation

  12. H-mode polarization measurements • Maximum polarization of 1.7 for peak emission shot • Other polarization measurements varied from 1.2-1.5

  13. Emission level not strongly correlated with Te at UHR 40 40 L-mode 1200 30 20 Te at UHR [eV] 800 Trad [eV] Te at UHR [eV] 20 0 400 10 0.6 0.8 0.4 0.2 1.0 0 Time [s] 0 0.2 0.0 0.6 0.4 300 Time [s] 14 25 400 250 20 10 200 300 Te at UHR [eV] 15 Trad [eV] Te at UHR [eV] 150 Trad [eV] 200 6 10 100 100 5 50 2 0 0 0 0 0.8 0.4 0.2 0.6 1.0 0.0 0.0 0.8 0.4 0.2 0.6 1.0 Time [s] Time [s]

  14. Harmonic emission much lower than 2005 campaign 120 80 Te at UHR [eV] 40 0 0.0 0.2 0.4 1.0 0.6 0.8 Time [s] 200 117982, H-mode (2005) 40 150 30 Trad [eV] 100 Te at UHR [eV] 20 50 10 0 0 0.0 0.8 0.4 0.2 0.6 1.0 Time [s]

  15. Density scale length larger in some H-modes 20 • Ln obtained with Thomson data factor of 2 less than reflectometer data • LnH-mode ≥ LnL-mode • Mode conversion region outside H-mode pedestal • Higher fluctuations in LnH-mode 15 Ln 10 5 0 0.0 0.2 0.4 0.6 0.8 1.0 Time [s] 5 10 4 8 Ln Ln 3 6 2 4 0.6 0.8 0.2 0.4 0.6 0.8 0.4 0.2 Time [s] Time [s]

  16. Future Work • Complete calibrations (including vacuum window) • More accurate mode conversion efficiency map • Previous ray-tracing relied on direct launching of EBW • B-X-O mode coupling and emission packages in GENRAY may provide more accurate results • Use J. Preinhaelter’s code to model H-mode emission • Analysis of gas puffing experiments • Analysis of TF ramping experiments • Correlation analysis of Ln and emission data • Complete upgrades for 2007 run campaign • Design XP for 2007 run to investigate low H-mode emission

More Related