摘要:

On 14 April 2003 at the Communications Research Center (CRC) in Ottawa, Ontario, a 5.85‐GHz transmitter beamed 3‐kW of microwave power to a remote rectifying antenna (i.e., rectenna) that delivered 6‐kV to a special ‘Ion‐Breeze’ Engine (IBE). Three of CRC’s 26.5‐cm by 31‐cm rectennas were connected in series to provide the ∼6‐kV output. RPI’s low‐voltage IBE thrusters performed well in a “world’s first” power‐beaming demonstration with rectennas and endoatmospheric ion‐propulsion engines. The successful tests were a low‐tech, proof‐of‐concept demonstration for the future full‐sized MicroWave Lightcraft (MWLC) and its air breathing ‘loiter’ propulsion mode. Additional IBE experiments investigated the feasibility of producing flight control forces on the MWLC. The objective was to torque the charged hull for ‘pitch’ or ‘roll’ maneuvers. The torquing demonstration was entirely successful. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1721021

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

An investigation on effects of a focused laser pulse for combustion enhancement characteristics was conducted for supersonic airstreams with a transverse hydrogen‐fuel injection. Numerical simulations using a time‐dependant Navier‐Stokes equation with finite‐rate chemistry were conducted to elucidate laser‐induced ignition and mixing enhancement characteristics. From the results, it was confirmed that, depending on the laser energy density and focal points, radicals, a shock wave, and shock‐induced local turbulences were being formed through the laser irradiation. Then recirculation zones with flamelets were induced. Moreover it was shown that these flamelets grew in moving upstream and downstream from the focal point up to 1 msec. From these results, it was shown that laser‐induced plasmas could be effective in both combustion reaction and mixing enhancements for the supersonic combustion. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1721022

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

An assessment of a novel laser‐electric hybrid propulsion system was conducted, in which a laser‐induced plasma was induced through laser beam irradiation onto a target and accelerated by electrical means instead of the direct acceleration only by using a laser beam. A fundamental study of newly developed rectangular laser‐assisted pulsed‐plasma thruster (PPT) was conducted. Inducing a short‐duration conductive plasma between electrodes with certain voltages, short‐duration switching or a discharge was achieved. At low‐voltage conditions (∼ 100 V), applied to electrodes or charged to a capacitor, it was confirmed that electric discharge can be achieved even under low voltage conditions. From the results, it was found that discharge duration at the low‐voltage case was as long as that of laser‐induced plasma. Therefore, the discharge in the low‐voltage case must be controlled with an incident laser pulse, or a laser‐induced plasma. While in high‐voltage cases (∼ 2000 V), the discharge duration was much longer than that of laser‐induced plasma. In this case, the laser‐induced plasma should be leading main discharge from a capacitor, where some amount of neutral components of vaporized propellant must be ionized through the discharge. Considering ratios of the laser energy to the discharge energies, the discharge process in the high‐voltage mode cases must be defined as the laser‐assisted electric discharge, or the laser‐assisted electric propulsion mode, while in the low‐voltage mode case with smaller electric energy, as the electrically‐assisted laser‐induced process, or the electric‐assisted laser propulsion mode. Moreover, plasma behaviors emitted from each thruster in various cases were observed with the ICCD camera. It was shown that the plasma behaviors were almost identical between low and high voltage cases in initial several hundred nanoseconds, however, plasma emission with longer duration was observed in higher voltage cases. Canted current sheet structures were also observed in the higher voltage cases using a larger capacitor. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1721023

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

A model is presented for sonic region radiation‐heated flow. Sonic combustion provides a direct and efficient heating method and can meet specific impulse and thrust requirements for orbital insertion and escape. The model allows investigation of flow geometry, real gas effects and stability issues using 1, 2 and 3‐dimensional simulations. Concept feasibility, design optimization and trade studies are possible with this model. The paper introduces the concept of end‐to‐end simulation whereby computer modeling is used for all aspects of beamed energy propulsion from source through path to propulsion module. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1721024

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

The present paper presents recent experimental results on the Laser‐SupportedDirectedEnergy “AirSpike” — DEAS in hypersonic flow achieved by the Laboratory of Aerothermodynamics and Hypersonics — LAH, Brazil. Two CO2TEA lasers, sharing the same optical cavity, have been used in conjunction with the IEAv 0.3m Hypersonic Shock Tunnel — HST to demonstrate the Laser‐Supported DEAS concept. A single and double laser pulse, generated during the tunnel useful test time, were focused through a NaCl lens upstream of a Double Apollo Disc model fitted with seven piezoelectric pressure transducers and six platinum thin film heat transfer gauges. The objective being to corroborate previous results as well as to obtain additional pressure and heat flux distributions information when two laser pulses are used. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1721025

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Compact accelerators employing laser‐foil interactions which have significant potentials for space propulsion applications were reviewed. A feasibility study was conducted for the use of this phenomenon to primary propulsion applications. In order to evaluate thrust performance of this accelerator, time‐gated imaging measurement with an ICCD camera was conducted for an Al foil target irradiated with an Nd:YAG laser set 1J/pulse with pulse width of 10nsec and wavelength of 1064nm. From the measurement, the maximum plasma speed was ∼ 100 km/sec. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1721026

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We propose a new concept controlling a satellite by a fiber laser loaded in it and demonstrated the acceleration of pendulum with 7kW/2n and 2kHz fiber laser, and measured the Cm of 16Ns/MJ corresponding to the scaling of YAG laser. This laser can be easily bundled to generate much larger power. For more efficient acceleration, we propose “metal‐free water cannon target”, the new concept of propulsion using only water. The momentum coupling coefficient of 2500[Ns/MJ] was achieved with vacuum pump oil instead of water, and we succeeded in controlling the driving direction by the system based on the new concept. This can be used for thrusting a satellite and controlling its posture in combination with fiber lasers. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1721027

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We found that water overlay on a metal layer is more effective than solid overlay. By using this target we demonstrated the successful flight of paper‐airplane of 5 cm‐size over a distance of 1–2m. In this paper, repetitive water supply system and levitation system are proposed for practical application, and examined by experiments. We succeeded in driving an object continuously using repetitive water supply and air slider. We also succeeded in driving 300g object by 0.5J laser using these equipments. In this paper, we try to find out a new possibility of water‐powered laser propulsion. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1721028

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Construction of a large scale natural gas pipeline network system in the Northeast Asian area has been proposed by several researchers, including Prof. Masaru Hirata, which will extend over tens of thousands of kilometers. To monitor the gas leakage, and to cope with any other hazardous problems, continuous surveillance of the network will be required.For this purpose, an environmental observation system for the large scale pipeline network is proposed. In this system unmanned airships are used as platforms for various environmental diagnostics. The unmanned airship is routed along the pipeline with the aid of GPS. Propulsion power of the air ship is transmitted from the ground bases by microwave; the microwave power stations are located every 100–200km along the pipeline.This paper describes the unmanned airships, environmental diagnostic systems, microwave generation tubes, and microwave powering system. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1721029

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

This paper investigates the physics of air plasma formation at the entrance of the MHD slipstream accelerator for the ‘tractor‐beam’ Mercury Lightcraft. Two scenarios are analyzed. The first addresses the needs of the minimum power airspike assuming that all the power required for air plasma formation must come from the remote laser beam. The second case considers the constant‐focus airspike and assumes that the breakdown criteria is satisfied by an on‐board auxiliary source (e.g., electric discharge, RF source, microwave source, or E‐beam). © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1721030

出版商:AIP    

年代:1904

数据来源: AIP