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34 巻, 6 号
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内田 成明2006 年 34 巻 6 号 p. 402-403
発行日: 2006/06/15
公開日: 2014/03/26
ジャーナル フリーPDF形式でダウンロード (260K) -
佐宗 章弘2006 年 34 巻 6 号 p. 404-407
発行日: 2006/06/15
公開日: 2014/03/26
ジャーナル フリーSurvey and prospects of laser propulsion technology in which a launched object breathes either ambient or tube-filled gas are presented. The technology utilizes repetitive laser pulses, and is subdivided to bell-, lightcraftand in-tube-types. Ablation of liquid or solid can enhance its thrust performance. Unsteady fluid dynamics in its impulse production processes involves jet formation due to Munroe effect, Rayleigh-Taylor and Richtmyer Meshkov instabilities, thereby warranting further basic and applied investigations.抄録全体を表示PDF形式でダウンロード (3670K) -
矢部 孝, 内田 成明2006 年 34 巻 6 号 p. 408-413
発行日: 2006/06/15
公開日: 2014/03/26
ジャーナル フリーWe overview a new laser propulsion concept that uses water overlay. This system realizes 100-1000 times larger thrust than single layer propulsion. The various applications to ship, engine and airplane are demonstrated. As a future concept, the use of solar-energy-pumped laser is discussed. The unsteady energy like sunlight and wind power is accumulated and stored in the form of magnesium. When the energy is needed, the magnesium-water reaction is used to produce the electricity as well as heat sources. The reaction product MgO is deoxidized into magnesium again by lasers that are generated by solar energy or wind-power. With such processes, we are able to realize a sustainable society.抄録全体を表示PDF形式でダウンロード (11498K) -
小紫 公也2006 年 34 巻 6 号 p. 414-418
発行日: 2006/06/15
公開日: 2014/03/26
ジャーナル フリーIn the proposed space propulsion systems powered by a CW laser, laser energy is converted to thermal energy of a propellant gas by means of a mechanical heat exchanger or a stationary Laser-Sustained Plasma (LSP). This paper describes mainly the physical processes in LSP formation and energy conversion in a gas flow bounded in a pressure chamber. The size and position of LSP, which are the function of static pressure and flow velocity of the propellant gas, strongly affect the laser absorption efficiency. Therefore, the chamber shape should be designed to optimize these flow parameters.抄録全体を表示PDF形式でダウンロード (9502K) -
内田 成明, 矢部 孝, 島田 義則2006 年 34 巻 6 号 p. 419-422
発行日: 2006/06/15
公開日: 2014/03/26
ジャーナル フリーApplicability of laser propulsion to orbital transfer vehicle, LOTV (=Laser Orbital Transfer Vehicle) was investigated based on experimental laser-plasma characterization and theoretical estimation. A laser intensity dependence of specific impulse, a basic characteristic of a propulsion system was measured. The results were used to estimate the size of the laser required to an LOTV system. A 10-ton class LOTV system was characterized in terms of transfer periods, laser power, pulse repetition rate and propellant size to show that a primary performance of the system is a realistic one.抄録全体を表示PDF形式でダウンロード (3648K) -
ミラボー レイク2006 年 34 巻 6 号 p. 423-428
発行日: 2006/06/15
公開日: 2014/03/26
ジャーナル フリーOn 2 October 2000, a 12.2-cm diameter, 50.6-gram laser-boosted rocket Lightcraft flew to a new altitude record of 71-meters (233-ft) at White Sands Missile Range (WSMR) in New Mexico. The PLVTS 10-kW pulsed carbon dioxide laser, located on the High Energy Laser Systems Test Facility (HELSTF) powered the record flight, as well as six others-two of which reached 48.4-m (159-ft) and 56-m (184-ft). These were the first outdoor vertical, spin-stabilized flights of laser Lightcraft. Besides nearly doubling the previous altitude record of 39 meters (128-ft) set on 9 July '99, the Model #200 Lightcraft simultaneously demonstrated the longest laser-powered free-flight, and the greatest ‘air time’ (i.e., launch-to-landing/recovery). With a modest investment of under a million dollars, a string of ever-increasing Lightcraft altitude records have been set over the past four years-since the first flight on 23 April 1997. This embryonic, propulsion concept embodies “disruptive technology” that promises to radically transform our ideas about global flight transportation and space launch systems, over the next 15 to 25 years.抄録全体を表示PDF形式でダウンロード (8102K) -
Andrew V. PAKHOMOV2006 年 34 巻 6 号 p. 429-434
発行日: 2006/06/15
公開日: 2014/03/26
ジャーナル フリーThe founders of Laser Propulsion (LP) viewed laser ablation as a key physical mechanism for generation of thrust. Three decades of systematic studies have shown that the role of laser ablation in LP is rather indirect and different from what has been expected. This paper reviews the effort to revise the original idea of using “direct” laser ablation of matter for propulsion, conducted at the University of Alabama in Huntsville. The study evolved from the formulation of the concept in 1999 to the first in-lab flight demonstrations in 2004. The physical principles of ablative laser propulsion (ALP) will be reviewed. The discussion will be focussed on our studies, conducted with three independent techniques: ion time-of-flight, force measurements and plasma imaging. From these experiments such characteristic parameters as specific impulse, coupling coefficient and efficiency were deduced. These results were finally corroborated by flight demonstration. The paper is concluded with discussion of future prospects for development of ALP.抄録全体を表示PDF形式でダウンロード (1190K) -
Hideyuki HORISAWA, Koki SASAKI, Akira IGARI, Itsuro KIMURA2006 年 34 巻 6 号 p. 435-441
発行日: 2006/06/15
公開日: 2014/03/26
ジャーナル フリーIn this paper, we describe the characteristics of novel laser-electric hybrid accelerators, in which laser-induced plasma generated through laser beam irradiation onto a solid target is additionally accelerated by electrical means instead of by direct acceleration using only a laser beam. As two typical cases of hybrid acceleration, a preliminary study, including thrust performance test with a torsion balance, ion current measurement, and ICCD camera observation, on laser-electrostatic and laser-electromagnetic hybrid accelerations was conducted. For the laser-electrostatic acceleration, it was confirmed that thrust characteristics were successfully improved with an acceleration electrode with either positive or negative potential. As for the laser-electromagnetic acceleration, it was shown that thrust performance could be improved wit抄録全体を表示PDF形式でダウンロード (8792K) -
萩谷 浩之, 内田 成明, 矢部 孝2006 年 34 巻 6 号 p. 442-446
発行日: 2006/06/15
公開日: 2014/03/26
ジャーナル フリーA scheme of laser propulsion using a heat exchange principle has been proposed. The scheme uses pressure of vaporized water (condensing steam nuclei) or other safe propellants and significantly reduces the complexity and technical hurdles of both engine structure and laser system compared to other laser propulsion schemes such as one utilizing laser ablation. In the proposed scheme, laser power is used for vaporization and overheating water molecule. To realize the scheme, CW-CO2 laser is adopted as a power source. This pap>Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, er describes the experimental characterization of laser radiation interaction with water vapor on which our thruster model design is based.抄録全体を表示PDF形式でダウンロード (921K) -
Kensuke MASUDA, Sayaka OHMORI, Tsunenori ARAI2006 年 34 巻 6 号 p. 447-449
発行日: 2006/06/15
公開日: 2014/03/26
ジャーナル フリーTo estimate the triplet state lifetime of Photodynamic therapy (PDT) under pulsed excitations, we measured the photosensitizer triplet state lifetimes by time resolved measurement of the singlet oxygen generated by PDT using the clinical photosensitizers, Talaporfin and Photofrin II®. By fitting the measured curve to nonlinear least-squares statistics, the photosensitizer triplet state lifetime was obtained. For Talaporfin, the triplet state lifetime measured at a high intensity of 1.67 MW/cm2 was 4.3 times longer than that measured at a low intensity of 0.20MW/cm2. In the case of Photofrin II, the measured lifetime was increased to 1.1 times. These results indicated that there might be oxygen depletion at high pulsed intensities in the case of Talaporfin, which was not observed with Photofrin II.抄録全体を表示PDF形式でダウンロード (389K)
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