Laser Impulse Generation in Flight

Sasoh, Akihiro; Ogawa, T.; Kim, Sukyum; Kawahara, Takehiro; Jeung, In‐Seuck; Yu, Xilong

doi:10.2514/6.2004-650

Cited by 4 publications

(5 citation statements)

References 7 publications

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“…Further refinements in the plugnozzle (i.e., off-axis parabolic) Lightcraft engine/vehicle, along with a more ideal laser source, will enable dramatic increases in engine performance throughout the subsonic, supersonic, and hypersonic regimes. Seoul National University and Pusan National University, both in South Korea, have collaborated with the numerical analysis on Sasoh's LITA concept (Sasoh, 2004).…”

Section: United Statesmentioning

confidence: 99%

“….............................. 14 Figure 1.6 LITA concept, upstream beam operation ...................... 15 Figure 1.7 LITA features in a pusher beam configuration (Sasoh, 2004) ....................... 15 Figure 1.8 The ALSPE concept vehicle (Rezunkov et al, 2005) ................................... 16 Figure 1.9 Laser-induced DEAS hypersonic experiments in Brazil. (Salvador, 2008) ... 17 (1973) and Richard (1989) vs. present experimental data from shroud undersurface (adjusted for shroud inclination).…”

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confidence: 99%

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Basic Research Investigations into Multimode Laser and EM Launchers for Affordable Rapid Access to Space (Volumes 1 and 2)

Myrabo¹,

Salvador²,

Kenoyer³

2010

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This basic research effort on pulsed airbreathing/rocket laser propulsion , investigates the physics of laser energy deposition into stationary and hypersonic working Ouids, inclusive of electrical breakdown, ignition of laser-supported detonation waves (LSD}, and blast wave propagation over thruster impulsegenerating surtaces. The future application of AFOSR interest for this basic research endeavor is the laser launch of nano-and micro-satellites (i.e. , 1-1 00 kg payloads} into Low Earth Orbit (LEO), at low cost and "on-demand." The present dual-pronged, combined experimental/numerical research campaigns centered on both static and hypersonic experiments with representative 20 and 30 laser-thruster geometries, using the Lumonics TEA-622 (-200J, -1 OOns) and K922M (20-40J, -100ns) C0 2 lasers. Laser scramjet experiments were pertormed in the T3 tunnel at the Henry T. Nagamatsu Laboratory of Aerothermodynamics and Hypersonics (HTNLAH). Time-dependent surtace pressure distributions were measured over thrust-generating surtaces following laser energy deposition; delivered impulse and momentum coupling coefficients (Cm) were obtained; Schlieren moviesof the impulse generation process were recorded with a high-speed Cord in digital camera, to study the laser breakdown/ blast wave expansion process, and evolving flow field structures in both stationary and hypersonic flow. Time-resolved visualizations of inlet and absorption chamber flowfields, enabled qualitative analysis of dominant phenomena impacting laser-propulsion physics.

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Section: United Statesmentioning

confidence: 99%

mentioning

confidence: 99%

Basic Research Investigations into Multimode Laser and EM Launchers for Affordable Rapid Access to Space (Volumes 1 and 2)

Myrabo¹,

Salvador²,

Kenoyer³

2010

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“…12). In LITA 50, a momentum coupling coefficient of 950 µ N/W was obtained with Xe at a fill pressure of 20 kPa [13].…”

Section: Impulse Enhancement In In-tube Configurationmentioning

confidence: 99%

“…Immediately in front of the ZnSe window, a plane-convex lens (focal length; 1660mm) is set. Currently, this experiment is in preparation [13].…”

Section: Impulse Generation In Free Flightmentioning

confidence: 99%

Propulsive Impulse Generation Using CO<sub>2</sub> TEA Lasers

Sasoh

Watanabe

Yu³

et al. 2004

MSF

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“…In most aerospace applications of air plasma flow (hypersonic flow around a reentry body [1][2][3][4], laser-driven blast wave [5][6][7][8], and plasma processing techniques using electric discharges), plasma internal states do not achieve local thermodynamic equilibrium (LTE). It is necessary to consider nonequilibrium properties of population distribution into each plasma internal state.…”

Section: Introductionmentioning

confidence: 99%

A fitting formula for radiative cooling based on non-local thermodynamic equilibrium population from weakly-ionized air plasma

Ogino¹,

Nagano²,

Ishihara³

et al. 2013

J. Phys.: Conf. Ser.

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Abstract.A fitting formula for radiative cooling with collisional-radiative population for air plasma flowfield has been developed. Population number densities are calculated from rate equations in order to evaluate the effects of nonequilibrium atomic and molecular processes. Many elementary processes are integrated to be applied to optically-thin plasmas in the number density range of 10 12 /cm 3 ≤ N ≤ 10 19 /cm 3 and the temperature range of 300 K ≤ T ≤ 40,000 K. Our results of the total radiative emissivity calculated from the collisional-radiative population are fitted in terms of temperature and total number density. To validate the analytic fitting formula, numerical simulation of a laser-induced blast wave propagation with the nonequilibrium radiative cooling is conducted and successfully reproduces the shock and plasma wave front time history observed by experiments. In addition, from the comparison between numerical simulations with the radiation cooling effect based on the fitting formula and those with a gray gas radiation model that assumes local thermodynamic equilibrium, we find that the displacement of the plasma front is slightly different due to the deviation of population probabilities. By using the fitting formula, we can easily and more accurately evaluate the radiative cooling effect without solving detailed collisional-radiative rate equations. IntroductionIn most aerospace applications of air plasma flow (hypersonic flow around a reentry body [1-4], laser-driven blast wave [5][6][7][8], and plasma processing techniques using electric discharges), plasma internal states do not achieve local thermodynamic equilibrium (LTE). It is necessary to consider nonequilibrium properties of population distribution into each plasma internal state. The nonequilibrium properties directly affect radiative emissivities and opacities, partition functions of internal energy modes, and thermal relaxations. These effects of nonequilibrium processes are still a problem that remains to be solved in those applications.For instance, we take a gas-driven laser-propulsion system whose thrust power is obtained through interaction with a propellant gas heated by external laser beam irradiation. After a focused laser breaks down the propellant gas, a blast wave is formed by the laser-produced plasma and propagates to the projectile through the surrounding gas. The performance of a gas-driven laser propulsion system depends heavily on the blast-wave dynamics and the plasma states sustaining it. Our previous work [8] numerically simulated a laser-driven blast wave

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Laser Impulse Generation in Flight

Cited by 4 publications

References 7 publications

Basic Research Investigations into Multimode Laser and EM Launchers for Affordable Rapid Access to Space (Volumes 1 and 2)

Basic Research Investigations into Multimode Laser and EM Launchers for Affordable Rapid Access to Space (Volumes 1 and 2)

Propulsive Impulse Generation Using CO<sub>2</sub> TEA Lasers

A fitting formula for radiative cooling based on non-local thermodynamic equilibrium population from weakly-ionized air plasma

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