- 著者
- Naoki ITO Daisuke KUWAHARA Yoshio NAGAYAMA Masayuki YOSHIKAWA Junko KOHAGURA Shoji SUGITO Atsushi MASE Yuichiro KOGI Tomokazu YOSHINAGA Soichiro YAMAGUCHI
- 出版者
- The Japan Society of Plasma Science and Nuclear Fusion Research
- 雑誌
- Plasma and Fusion Research (ISSN:18806821)
- 巻号頁・発行日
- vol.10, pp.3402034-3402034, 2015-04-16 (Released:2017-01-23)
- 参考文献数
- 10
- 被引用文献数
- 4
Microwave to millimeter-wave diagnostics techniques, such as interferometry, reflectometry, scattering, and radiometry, have been powerful tools for diagnosing magnetically confined plasmas. The resultant measurements have clarified several physics issues, including instability, wave phenomena, and fluctuation-induced transport. Electron cyclotron emission imaging has been an important tool in the investigation of temperature fluctuations, while reflectometry has been employed to measure plasma density profiles and their fluctuations. We have developed a horn-antenna mixer array (HMA), a 50 - 110 GHz 1D antenna array, which can be easily stacked as a 2D array. This article describes an upgrade to the horn mixer array that combines well-characterized mixers, waveguide-to-microstrip line transitions, intermediate frequency amplifiers, and internal local oscillator modules using a monolithic microwave integrated circuit technology to improve system performance. We also report on the use of a multi-channel HMA system.
- 著者
- IMADERA Kenji KISHIMOTO Yasuaki
- 出版者
- The Japan Society of Plasma Science and Nuclear Fusion Research
- 雑誌
- Plasma and Fusion Research (ISSN:18806821)
- 巻号頁・発行日
- vol.6, pp.1201004-1201004, 2011
- 被引用文献数
- 3
The non-canonical Lie perturbation method for analyzing relativistic electron beams in free electron lasers [Y. Kishimoto et al., Phys. Plasmas 2, 1316 (1995)] is extended to the case with harmonic gyro-resonance due to the coexistence of a focusing wiggler and an axial guiding field, which allow the maximum beam current to be increased. By using non-canonical guiding-center variables, we have solved the particle motion not only far from the harmonic gyro-resonance but also near the resonance. Far from the resonance, the maximum beam current is found to increase in proportion to (B<sub>g</sub>/B<sub>w</sub>)<sup>2</sup> (B<sub>w</sub> and B<sub>g</sub> are the strength of the wiggler and guiding fields, respectively). On the other hand, near the resonance, the beam is found to be confined in a finite radial region and then transmitted because of higher order secular perturbations.
- 著者
- Soichiro IKUNO Norihisa FUJITA Yuki KAWAGUCHI Taku ITOH Susumu NAKATA Kota WATANABE Hiroyuki NAKAMURA
- 出版者
- The Japan Society of Plasma Science and Nuclear Fusion Research
- 雑誌
- Plasma and Fusion Research (ISSN:18806821)
- 巻号頁・発行日
- vol.6, pp.2401069, 2011-07-01 (Released:2012-01-23)
- 参考文献数
- 9
- 被引用文献数
- 1 1
The variable preconditioned (VP) Krylov subspace method on multi Graphics Processing Unit (GPU) is numerically investigated. Besides, the linear system obtained by finite element method with an edge element is adopted for the problem. The results of computations show that VP conjugate gradient method on multi GPU demonstrated significant achievement than that of CPU. Especially, VP conjugate gradient method on multi GPU is 4.35 times faster than that of CPU. However, transmission rate between the PC using Gigabit Ethernet is the bottleneck of the performance.