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Volume 125, Issue 9
Displaying 1-6 of 6 articles from this issue
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Special Issue on Pulsed-Power Technology and Applications
Special Issue Review
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Hidenori Akiyama, Taisuke Fudamoto, Sunao Katsuki, Takao Namihira, Tak ...2005 Volume 125 Issue 9 Pages 717-722
Published: 2005
Released on J-STAGE: December 01, 2005
JOURNAL FREE ACCESSRecent developments of pulsed power generators have been concentrated into the developments of repetitively operated pulsed power generators. In addition, the stability and quality of the pulsed power output have been pursued. The developments of these high-quality pulsed power generators enable the industrial applications of pulsed power. Industrial applications are described in the fields of environmental, medical, nanotechnologies and recycling applications.View full abstractDownload PDF (8869K)
Special Issue Paper
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Jong-Gu Kwak, Song-Jong Wang, Jae-Sung Yoon, Bong-Guen Hong2005 Volume 125 Issue 9 Pages 723-726
Published: 2005
Released on J-STAGE: December 01, 2005
JOURNAL FREE ACCESSA 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.View full abstractDownload PDF (436K) -
Yoshinori Tokoi, Tadashi Ikeuchi, Hisayuki Suematsu, Weihua Jiang, Kiy ...2005 Volume 125 Issue 9 Pages 727-732
Published: 2005
Released on J-STAGE: December 01, 2005
JOURNAL FREE ACCESSCopper 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.View full abstractDownload PDF (8323K) -
Kazuo Ogura, Kiyofumi Komiyama, Masakazu Sakai, Daisuke Yamada, Hiroki ...2005 Volume 125 Issue 9 Pages 733-738
Published: 2005
Released on J-STAGE: December 01, 2005
JOURNAL FREE ACCESSPerformance 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.View full abstractDownload PDF (7328K) -
Hoshiyuki Yamazaki, Makoto Iwai, Yoshitaka Suzuki, Hirokazu Takagi, Os ...2005 Volume 125 Issue 9 Pages 739-743
Published: 2005
Released on J-STAGE: December 01, 2005
JOURNAL FREE ACCESSNonaxisymmetric 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.View full abstractDownload PDF (9047K) -
Shoumou Miao, Xiaopeng Zhu, Mingkai Lei, Hisayuki Suematsu, Weihua Jia ...2005 Volume 125 Issue 9 Pages 744-748
Published: 2005
Released on J-STAGE: December 01, 2005
JOURNAL FREE ACCESSA 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.View full abstractDownload PDF (7084K)
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