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FAM launcher design. M.Goniche, J.Hillairet CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France J.Belo IST, Lisboa, Portugal HCD08-03-01 EFDA Task Meeting in Cadarache, 8-9 March 2010. Motivations. Reference design ( PAM) has clear advantages but also some disadvantages, namely:
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FAM launcher design M.Goniche, J.Hillairet CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France J.Belo IST, Lisboa, Portugal HCD08-03-01 EFDA Task Meeting in Cadarache, 8-9 March 2010
Motivations Reference design (PAM) has clear advantages but also some disadvantages, namely: - Loss of directivity when n/nco > 2 => confirmed (see Int. Report) - Possibly for ITER, lower output power => to be checked
a = 50 mm 120º b = 6.99 mm 120º e = 3 mm 120º 240º 120º geometric phase shifter 0º 120º 120º 240º 120º 120º 0º 120º 120º 120º 240º General design (N||=2.0) • Overall arrangement of DDD2001 PAM: • N|| = 2.0 [maintained]; • bi-junction based design [maintained]; • 8 active wg per module [maintained]; • fully active (no passive wg) [changed]; • 120ºphasing between output wg [changed]; • a=50mm(output wg height) [reduced]; • b=6.99mm (output wg width) [reduced]; • e=3mm (septa) [maintained]; • 120º geometric phase shifters [changed] • L = 1.62 & 1.17m[unchanged]
1.17m 1.62m b=29mm b=16.98mm b=6.99mm Long FAM (1.62m) Short FAM (1.17m) • 120º phase shifters: • /4 step transformers • heights: a = 42mm & 44mm • 120º phase shifters: • /4 step transformers • heights: a = 42mm
Short FAM (1.17m) S1j S1j= 9.03 0.04 dB @ 5GHz S11 = 41.6 dB @ 5GHz Phase difference between output wg =120º 1.3º @ 5GHz E-field (1W input)
Average Power Reflection Coefficient (3 modules of 8 Active Waveguides) PAM 4A+4P RC < 2% when n/ncut-off > 1.5
20MW 20MW Maximum Electric Field PAM 4A+4P Emax < (5/3.7)*5 = 6.8 kV/cm for n/ncut-off>2 Higher field than that of PAM
Maximum Coupled Power @ Emax=6.7kV/cm 20MW can be coupled for n/ncut-off>2 Higher power capability for PAM when n/ncut-off<4.5
N// spectra FAM PAM
P(N//>1) P(N//=N//0) FAM P(N//)/N//2 PAM Directivity Good directivity for the FAM when n/ncut-off>2
Directivity vs. Curent Drive CD has been computed by LUKE with real N// spectra at various densities (see WG1 intermediary report) Driven current varies as the normalized directivity
Golbal Current Drive Capability PAM has a better CD capability when n/ncut-off<3
Conclusions • A 8 WG FAM with 120° internal phasing and reduced height (cooling) has been designed with same length as the 4A+4P WG PAM (1.17m) • Good coupling (RC <2%) is achieved when n/ncut-off>1.5 • 20 MW can be coupled at Emax=6.8kV/cm • Good directivity for n/ncut-off>2 • PAM has expected better performance when n/ncut-off<3 • To check with RT/FP code • Change for 90° FAM ?