Summary: Gyrotron Development

Transcription

1 Summary: Gyrotron Development State-of-the-Art of Industrial Megawatt-Class Longpulse Fusion Gyrotrons (f 140 GHz) with TEM 00 -Output Denisov et al., Felch et al., Sakamoto et al., Erckmann et al. Company Frequency [GHz] Cavity Mode Power [MW] Efficiency [%] Pulse Length [min.] Gun Type CPI 140 TE 28, (SDC) 30 Diode TED / EU 140 TE 28, (SDC) 30 Diode GYCOM / IAP 170 TE 25, (SDC) 1.7 Diode (SDC) 5 Diode TOSHIBA / IAEA 170 TE 31, (SDC) 13.3 Triode (SDC) 60 Triode 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 1

2 Summary: Gyrotron Development Hysteresis Maximum eff. 56% Output Power (MW) Hard self-excitation region TE31,8 TE30, Cavity field (T) 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 2

3 Ç Ç±ÇÃÉ séné`éç ¾å Ç ÈǞǽ Ç ÇÕ ïkóvç- ÇÅB TIF ÅiàèkǻǵÅjê Lí ÉvÉ çéoéâ ÉÄ QuickTimeý Dz Summary: Gyrotron Development High Efficiency Operation Anode Voltage (kv) (1) Increase of anode voltage (α) (2) Decrease of cavity field Anode Over Current Optimized 0.82MW 0.6MW-1h Operation 0.8MW 0.7MW 0.6MW Initial (2) Mode jump to TE30,8 (1) Cavity Field (T) 0.5MW 0.4MW 0.82MW-56%-600s High Efficiency Operation (1) (2) Depressed Collector Volt. Anode Volt. Cathode Volt. QuickTimeý Dz TIFFÅiàèkǻǵÅj êlí ÉvÉçÉOÉâÉÄ Ç Ç±ÇÃÉsÉNÉ`ÉÉǾå ÇÈÇžÇ½Ç ÇÕïKóvÇ-ÇÅB Magnetic Field Beam Current RF Collector Temp Power 0s 100s 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 3

4 Summary: Gyrotron Development State-of-the-Art of Advanced MW Gyrotrons with TEM 00 -Output Denisov et al., Felch et al., Sakamoto et al., Piosczyk et al. Company Frequency [GHz] Cavity Mode Power [MW] Efficiency [%] Pulse Length [sec.] Gun Type CPI / MIT/GA TED / EFDA TE 22,6 Cylindrical TE 31,7 Coaxial TE 34,19 Coaxial (SDC) Diode (SDC) Diode Magnet not ready Mode Competition Diode GYCOM / IAP TOSHIBA / JAEA TE 28,12 Cylindrical TE 31,12 Cylindrical (SDC) 0.1 Diode Triode 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 4

5 Summary: Gyrotron Development Photo of the assembled 2 MW, CW, 170 GHz Coaxial Cavity ITER Gyrotron ion getter pump collector RF output window mirror box electron gun Technical Meeting for ITER EC H &CD System M. Thumm 33 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 5

6 Summary: Gyrotron Development State-of-the-Art of Advanced, Industrial, Frequency-Tunable 1 MW Gyrotrons with TEM 00 -Output Denisov et al., Rao et al., Wagner et al. 1) Two-Frequency Gyrotron at 105 and 140 GHz with single-disk CVD diamond window 2) Four-Frequency Gyrotron at 105, 117, 127 and 140 GHz with CVD diamond Brewster window. A gyrotron with BN Brewster window was successfully tested at GYCOM at 11 frequencies ( GHz), power of MW and pulses of msec. Company GYCOM /IAP Frequency [GHz] Cavity Mode Power [MW] Efficiency [%] Pulse Length [sec.] Gun Type 105 TE 17, (SDC) 10 Diode 140 TE 22, (SDC) 10 Diode Indian ITER GHz start-up gyrotron can be developed from: (1) GYCOM 4-f gyrotron, (2) TED 140 GHz gyrotron, (3) CPI 110 GHz gyrotron, (4) TOSH./JAEA 110 GHz gyrotron 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 6

7 Summary: Gyrotron Development 1) Electron Gun (Magnetron Injection Gun: MIG) (a) Diode type (single anode) vs. Triode type (plus modulation anode) simple, only one power supply two power supplies, but independent control of pitch factor (b) Azimuthal homogeneity of cathode emitter ring improved due to better QA 2) Gyrotron Magnet (a) Conventional LHe cooling vs. Cryogen-free magnets EU, RF, US (3x110 GHz tubes) JA, US (3x110 GHz tubes) 3) Beam Tunnel (a) Absorbing dielectric/copper vs. SiC disks (e.g. EU) QA! (e.g. JA) 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 7

8 Summary: Gyrotron Development 4) Cavity Glidcop vs. Oxygen-free copper, but always rounded contours for mode purity 5) Quasi-Optical Mode Converter All the Parties employ a slightly conical, dimpled-wall launcher with longitudinal and azimuthal mode bunching for reduction of diffraction losses and generation of a Gaussian-like power distribution (97-98 %) - IAP has efficient synthesis codes - Very high Gaussian mode content (99%) can be achieved using mirrors with adapted, non-quadratic curvature 6) Output Window All the Parties employ CVD-diamond windows Suppliers: Element Six, UK, I.D. = 106 and 75 mm (production: and 2.45 GHz) Diamond Materials, Germany, I.D. = 75 mm (2.45 GHz) IAP/GYCOM, Russia, I.D. = 75 mm?? (2.45 and 30 GHz!!) 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 8

9 Summary: Gyrotron Development 7) Collector All the Parties employ single-stage depressed collectors (SDC) Danger of collector failures due to cyclic fatique/recrystallization! Counter measures: GYCOM: shaping of the collector contour to expand the interception area of e-beam with the collector surface CPI: iron shielding used to expand the e-beam, Glidcop instead of Copper? increase of sweeping frequency IPP/FZK: combined transversal field sweeping (TFSS) and vertical sweeping (VFSS) of the e-beam (Erckmann et al.) peak power deposition is reduced by a factor of 2 Collector for 170 GHz, 2 MW EU ITER Gyrotron is feasible!! 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 9

10 Summary: Gyrotron Development CRPP-IPP-IPF-CEA FUSION Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft FZK - EURATOM ASSOCIATION Optimization of Collector Lading All gyrotrons are equipped with a standard vertical magnetic field sweeping system Peak loading of the collector can be reduced ( 2) by additional rotating transverse field sweeping system TFSS with VFSS, DC-0.5A, AC 12A T+V220_0,5DC_8AC z [mm] IVEC 2007, Kitakyushu, Fukuoka, Japan, May 15-17, 2007; G. Gantenbein 19 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 10

11 Design and Losses of the ECH Transmission Lines for ITER Rasmussen et al., Han, Temkin et al. Waveguide Layout Considerations - TL layout is evolving - minimum number of miter bends (if possible 90 ) - adequate supports and alignment fixtures - allow for waveguide and vessel thermal expansion - allow for disruptions and seismic events - minimize costs and maintenance Compatibility with 2 MW unit power for EU gyrotron and later upgrade of ECH system, waveguide switches and polarizers? (2 MW components are commercially available from GA) High Power Tests in US test stand with resonant ring and low power CW gyrotron R&D , Design , Production and QA tests , Delivery th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 11

12 Summary: Transmission Line What is required to deal with seismic or vessel displacement events Seismic gap U-Bend or Mechanical fuse? Flex line DDD specifies no microwave leakage DAR IAEA ITER ECRH-TM June 6-9, th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 12

13 Resonant ring to be used in US test stand 140 GHz ~ 300 kw cw gyrotron available now A >500 kw cw 170 GHz gyrotron system will be purchased for prototype testing Test full scale system at > 2 MW (gain of 10-30) - Long waveguide runs - Miter bends - Polarizers & loads - Pump-outs & bellows QuickTime and a Photo - JPEG decompressor are needed to see this picture QuickTime and a Photo - JPEG decompressor are needed to see this picture QuickTime and a Photo - JPEG decompressor are needed to see this picture QuickTime and a Photo - JPEG decompressor are needed to see this picture DAR IAEA ITER ECRH-TM June 6-9, th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 13

14 LOSS FOR ITER T/L Losses ITER DDD 5.2 This estimate MOU loss 0.22 db* <0.01 db Injection loss Coupling loss, Tilt, Offset db db Intrinsic loss Miter bends (7) Polarizers (2) Extrinsic loss 100 m WG WG Sag WG Tilt/Offset db db 0.19 db db db db db Other loss (many items) db db Total loss Loss without MOU Loss 0.65 db / 14% 0.43 db / 10% 0.49 db / 11% 0.49 db / 11% * Stray Radiation (Kasugai, 2001) 6 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 14

15 HE 11 MODE MITER BEND 2.17 E0 2.0 E-10 Input Gaussian Beam PML Boundaries HFSS Simulation of a mm Corrugated Waveguide at 110 GHz (a/λ = 5.82) Used on DIII-D 14 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 15

16 T/L Cold Test Results Three methods for loss measurements: Vector Network Analyzer (VNA) GHz band (at MIT) and GHz band (on order) Radiometry Compare transmitted power from hot/cold black body sources Substitution Compare transmitted power with / without device under test. Tested corrugated transmission lines 140 GHz T/L, 12.7 mm from T. Keating, UK 250 & 460 GHz T/L made at MIT (Woskov et al., IEEE MTT 2005) 170 GHz ITER T/L Parts from GA, arrived 2 weeks ago Pyroelectric camera measurements Evaluation of mode content in T/L 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 16 18

17 Plaum et al. Optimum shape of corrugation profile for low-loss square and cylindrical waveguides Direct Numerical Simulation - Measurements with 3-Mirror Resonator 2D problem solved using a standard FDTD method with periodic boundary condition (sufficient to consider only a single corrugation period) Result: Optimized corrugation profile with respect to propagate the Balanced Hybrid Mode - minimum losses - E/H 180 phase difference (also for design of optimum polarizers) Profile is more rectangular rounded (with slot width larger than tooth width) than sinusoidal 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 17

18 Takahashi et al., Sakamoto et al., Henderson et al., Goodman et al. High Power HE11 Waveguide Tests/Losses in Miter Bends (I.D. = 63.5 mm, Al) 40 m waveguide, 6 miter bends, 1 switch, 2 loads (CCR) with 2 pre-loads 170 GHz, 0.5 MW, 1000 s Mode conversion losses/diffraction losses in miter bends: 50 % of losses in low order forward modes, 25 % in high order forward modes 25 % in high order backward modes. Strong absorption of high order modes. Displacements lead to higher losses. Forced cooling is needed for the ITER TL Plans to test at 2 MW equivalent (miter bends mirrors/switches with higher absorption) Wagner et al.: Test of HE11 line of ASDEX Upgrade at 105 and 140 GHz (10s) 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 18

19 Transmission line( 63.5mm dia.) Gyrotron 1MW Dummy load Miter bends Transmission eff. 89% 40mWaveguide +7 bends From gyrotron to dummy load 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 19

20 DOUBLE-DISC WINDOW (design and construction: FZK Karlsruhe) 2007 International Conference on Pulsed Power and Plasma Science, June 17-22, 2007, Albuquerque, New Mexico, USA 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 20

21 DOUBLE-DISC WINDOW COLD TEST Calculated - Disc distance mm Measured Vacuum (room temperature) 0-10 Reflexion / db Frequency / GHz 2007 International Conference on Pulsed Power and Plasma Science, June 17-22, 2007, Albuquerque, New Mexico, USA 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 21

22 Kasparek et al. FAst DIrectional Switch (FADIS): Narrow Band Diplexer (waveguide or quasioptical) Optimum NTM stabilization by EC current drive in the O-point of two magnetic islands or parallel usage of UL and EL in ITER! Switching between two launchers: no waste of power! Switching by frequency-shift keying (freq. up to 20 khz at 0.5 MW, 140 GHz/W7-X) Experimental switching contrast: 99% non-resonant channel 94% resonant channel Open questions to be solved: - Long-term phase coherence of optical elements - Mechanical stabilization/control of diplexer - Frequency control of gyrotron with negligible power loss 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 22

23 Design of a resonant diplexer for test at 1 MW / 140 GHz matching optics for input beam matching optics for output beam 1 Compact design (< 1 m 3 ) the unloaded Q of the cavity is , loaded Q is maximum power gain within the cavity is 3.7, 4-mirror resonator matching optics for output beam 2 prototype! all mirrors: aluminium, un-cooled for input power of 1 MW, the maximum RF electric field corresponds to an RF power density of 0.8 MW/cm 2 (below the RF breakdown threshold of 1 MW/cm 2 ) 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 23

24 High-power test at the ECRH system of W7-X Installation in the beam duct of the ECRH system on W7-X: input beam from the rear outputs dumped in CCR loads power monitoring by grating couplers Top mirror with motor drive for remote tuning of the resonator 1. Arcing test at 500 kw: only infrequently, not a problem! max. power density on grating 0.5 MW/cm 2 Limit (atm. pressure): 1 MW/cm 2 4th IAEA Technical Meeting on ECRH Physics and Technology for ITER M. Thumm 24