電気学会論文誌A(基礎・材料・共通部門誌)
Online ISSN : 1347-5533
Print ISSN : 0385-4205
ISSN-L : 0385-4205
125 巻, 9 号
選択された号の論文の6件中1~6を表示しています
Special Issue on Pulsed-Power Technology and Applications
特集解説
特集論文
  • Jong-Gu Kwak, Song-Jong Wang, Jae-Sung Yoon, Bong-Guen Hong
    2005 年 125 巻 9 号 p. 723-726
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    A 2 MW transmitter with a frequency ranging from 30 to 60 MHz is used for the KSTAR ICRF heating source and it is necessary to equip it with a dummy load which has a low VSWR above the second or third harmonic frequency for testing the 2 MW transmitter. The resistive film type is well known as a non-inductive dummy load, however it can't be used above 300 kW because of problem at the surface adhesion between the ceramic substrate and the resistive film or sputtered carbon which imposes a limit on the power density of the film resistor. So, above 1 MW the most promising candidate is the soda water dummy load where the soda water plays a role in both the rf power absorbing medium and the cooling water. In this work, the electrical and mechanical design requirements of the 2 MW soda dummy load are introduced and RF characteristics are discussed using a lumped circuit model and a numerical analysis.
  • Yoshinori Tokoi, Tadashi Ikeuchi, Hisayuki Suematsu, Weihua Jiang, Kiy ...
    2005 年 125 巻 9 号 p. 727-732
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    Copper nanosized powders were successfully synthesized by pulsed wire discharge (PWD) in high-speed gas flow. The maximum pressure of the gas blowing from the gas puff apparatus developed for PWD was 22 kPa at plenum pressure of 0.4 MPa. The experimental results have shown that, by using gas puff at background pressure of 130 Pa, the electrical energy deposition into the wire reached 40 J, which is almost the same as that obtained at pressure of 5 kPa without gas puff. However, the average particle size decreased from 39 nm (at steady pressure of 5 kPa) to 16 nm (at background pressure of 130 Pa with gas puff). Therefore, it has been proved that the gas puff has significant effect in the reduction of average particle size.
  • Kazuo Ogura, Kiyofumi Komiyama, Masakazu Sakai, Daisuke Yamada, Hiroki ...
    2005 年 125 巻 9 号 p. 733-738
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    Performance of oversized backward wave oscillators (BWOs) is investigated. Due to the axial mode operation, there exists a critical value of beam energy for the oscillation, i.e., a starting energy. The output power depends on the beam radius and voltage. The maximum output powers are above 100 kW (K-band) and above 50 kW (Q-band). The corresponding quality factor Pf 2 is about 6×104 [kW·GHz2]. By changing the condition at the SWS end, an enhanced performance of the K-band oversized BWO is observed in a low magnetic field region about 0.4 T.
  • Hoshiyuki Yamazaki, Makoto Iwai, Yoshitaka Suzuki, Hirokazu Takagi, Os ...
    2005 年 125 巻 9 号 p. 739-743
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    Nonaxisymmetric Cherenkov and slow cyclotron instabilities in a backward wave oscillator are investigated by using a new version of self-consistent linear theory. The slow cyclotron instability as well as Cherenkov instability can be driven by an axial electron beam without any initial perpendicular velocity. In a low magnetic field region, the radial displacement of beam plays an important role in the beam interactions. The slow cyclotron instability becomes strong, when the perturbed cyclotron motion and the electromagnetic wave rotate in the same direction. The rotational direction of electromagnetic wave also affects the Cherenkov instability.
  • Shoumou Miao, Xiaopeng Zhu, Mingkai Lei, Hisayuki Suematsu, Weihua Jia ...
    2005 年 125 巻 9 号 p. 744-748
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    A complementary study on experimental observation and theoretical modeling has been performed to investigate the ablation behavior on titanium irradiated by high-intensity pulsed ion beams (HIPIB) with energy density of 70 J/cm2 up to 3 shots. The surface morphology with a typical waviness feature on the irradiated surface was observed by scanning electron microscopy (SEM). The observed surface morphology indicates a severer ablation in the center of irradiated area, leading to a fluctuation of liquid layer spreading radially to the peripheral area, due to the spatial distribution of ion beam energy density along the radial direction. The ablation process was simulated from the modeling of heat transfer in the irradiated samples using an axisymmetric model based on enthalpy formulation. The computational results are in good agreement with the experimental findings in the ablation mass with a trend of severer ablation in the center of irradiated area.
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