DocumentCode :
1622751
Title :
Plasma scattering measurement by using a submillimeter wave gyrotron as a radiation source
Author :
Ogawa, I. ; Idehara, T. ; Itakura, Y. ; Hori, T. ; Wagne, D. ; Thumm, M.
Author_Institution :
Res. Center for Dev. of Far-Infrared Region, Fukui Univ., Japan
Volume :
2
fYear :
2004
Firstpage :
501
Abstract :
An FU II gyrotron was applied as a submillimeter wave radiation source for plasma scattering measurements of the compact helical system (CHS) in the National Institute for Fusion Science (NIFS) in Japan. The stabilization of the gyrotron output and the high quality probe beam are required to improve the performance of the measurements. The outputs (cw operation, f=301 GHz, P∼20 W) of the FU IV gyrotron are stabilized (ΔP/P∼1%, Δf∼10 kHz) by decreasing the fluctuations of the potentials (ΔVk∼0.6 V, ΔVa∼0.2 V), by introducing smoothing circuits consisting of a resistor, an induction coil and a capacitor. Further stabilization of output frequency (Δf<1 kHz) is attained by applying a phase lock loop. A high purity mode operation is a prerequisite for effective conversion of the output radiation into the probe beam for scattering measurements. We have constructed a new gyrotron, namely, the FU VA gyrotron, which has a carefully designed resonant cavity. The measurements of the radiation patterns have confirmed high-purity mode operation.
Keywords :
cavity resonators; frequency stability; gyrotrons; phase locked loops; plasma diagnostics; scattering; smoothing circuits; submillimetre wave generation; submillimetre wave tubes; 20 W; 301 GHz; FU II gyrotron; FU IV gyrotron; FU VA gyrotron; capacitor; compact helical system; gyrotron output stabilization; high purity mode operation; high quality probe beam stabilization; induction coil; output frequency stabilization; phase lock loop; plasma scattering measurement; radiation pattern measurements; resistor; resonant cavity; smoothing circuits; submillimeter wave gyrotron; submm-wave radiation source; Gyrotrons; Nuclear and plasma sciences; Particle beam measurements; Plasma measurements; Plasma sources; Plasma waves; Probes; Scattering; Submillimeter wave devices; Submillimeter wave measurements;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Physics and Engineering of Microwaves, Millimeter, and Submillimeter Waves, 2004. MSMW 04. The Fifth International Kharkov Symposium on
Print_ISBN :
0-7803-8411-3
Type :
conf
DOI :
10.1109/MSMW.2004.1345978
Filename :
1345978
Link To Document :
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