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Title: Blast Wave Formation by Laser-Sustained Nonequilibrium Plasma in the Laser-Driven In-Tube Accelerator Operation

Abstract

Understanding the dynamics of laser-produced plasma is essentially important for increasing available thrust force in a gas-driven laser propulsion system such as laser-driven in-tube accelerator. A computer code is developed to explore the formation of expanding nonequilibrium plasma produced by laser irradiation. Various properties of the blast wave driven by the nonequilibrium plasma are examined. It is found that the blast wave propagation is substantially affected by radiative cooling effect for lower density case.

Authors:
; ;  [1];  [2]
  1. Department of Aeronautics and Space Engineering, Tohoku University, Sendai 980-8579 (Japan)
  2. Institute of Fluid Science, Tohoku University, Sendai 980-8577 (Japan)
Publication Date:
OSTI Identifier:
20800236
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 830; Journal Issue: 1; Conference: 4. international symposium on beamed energy propulsion, Nara (Japan), 15-18 Nov 2005; Other Information: DOI: 10.1063/1.2203261; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ACCELERATION; ACCELERATORS; COMPUTER CODES; DETONATION WAVES; LASER RADIATION; LASER-PRODUCED PLASMA; LASERS; NON-EQUILIBRIUM PLASMA; OPERATION; PROPULSION; PROPULSION SYSTEMS; RADIATIVE COOLING; TUBES; WAVE PROPAGATION

Citation Formats

Ogino, Yousuke, Ohnishi, Naofumi, Sawada, Keisuke, and Sasoh, Akihiro. Blast Wave Formation by Laser-Sustained Nonequilibrium Plasma in the Laser-Driven In-Tube Accelerator Operation. United States: N. p., 2006. Web. doi:10.1063/1.2203261.
Ogino, Yousuke, Ohnishi, Naofumi, Sawada, Keisuke, & Sasoh, Akihiro. Blast Wave Formation by Laser-Sustained Nonequilibrium Plasma in the Laser-Driven In-Tube Accelerator Operation. United States. doi:10.1063/1.2203261.
Ogino, Yousuke, Ohnishi, Naofumi, Sawada, Keisuke, and Sasoh, Akihiro. Tue . "Blast Wave Formation by Laser-Sustained Nonequilibrium Plasma in the Laser-Driven In-Tube Accelerator Operation". United States. doi:10.1063/1.2203261.
@article{osti_20800236,
title = {Blast Wave Formation by Laser-Sustained Nonequilibrium Plasma in the Laser-Driven In-Tube Accelerator Operation},
author = {Ogino, Yousuke and Ohnishi, Naofumi and Sawada, Keisuke and Sasoh, Akihiro},
abstractNote = {Understanding the dynamics of laser-produced plasma is essentially important for increasing available thrust force in a gas-driven laser propulsion system such as laser-driven in-tube accelerator. A computer code is developed to explore the formation of expanding nonequilibrium plasma produced by laser irradiation. Various properties of the blast wave driven by the nonequilibrium plasma are examined. It is found that the blast wave propagation is substantially affected by radiative cooling effect for lower density case.},
doi = {10.1063/1.2203261},
journal = {AIP Conference Proceedings},
number = 1,
volume = 830,
place = {United States},
year = {Tue May 02 00:00:00 EDT 2006},
month = {Tue May 02 00:00:00 EDT 2006}
}
  • Flow visualizations of the interaction between a laser-pulse-generated plasma and a shock wave driven by it have been experimentally conducted. The configuration of the experimental set-up corresponds to the laser-driven, in-tube accelerator. Primary-mode deformation of the plasma is governed by Richtmyer-Meshkov instability which is produced by the vector product between the pressure and density gradients, which in turn correspond to a reflected shock wave and to the plasma, respectively. Higher-mode contact surface deformations are supposedly originated in Rayleigh-Taylor instability in the shrinkage phase of the plasma, and is enhanced due to the passage of the reflected shock wave.
  • To achieve a higher thrust performance in the laser-driven in-tube accelerator operation, numerical analysises have been carried out. The computational code covers from the generation of the blast wave to its interactions with the projectile and the acceleration wall. The thrust history and the momentum coupling coefficient evaluated from the numerical simulation depend on the fill pressure and the projectile shape. The confinement effect can be clearly found using the projectile attached with a shroud.
  • At Tohoku University, experiments of Laser-driven In-Tube Accelerator (LITA) have been carried out. In order to observe the initial state of plasma and blast wave, the visualization experiment was carried out using the shadowgraph method. In this paper, dependency of initial plasma size on LITA performance is investigated numerically. The plasma size is estimated using shadowgraph images and the numerical results are compared with the experimental data of pressure measurement and results of previous modeling.
  • Via three-dimensional particle-in-cell simulations, the self-mode-transition of a laser-driven electron acceleration from laser wakefield to plasma-wakefield acceleration is studied. In laser wakefield accelerator (LWFA) mode, an intense laser pulse creates a large amplitude wakefield resulting in high-energy electrons. Along with the laser pulse depletion, the electron bunch accelerated in the LWFA mode drives a plasma wakefield. Then, after the plasma wakefield accelerator mode is established, electrons are trapped and accelerated in the plasma wakefield. The mode transition process and the characteristics of the accelerated electron beam are presented.
  • We have performed axisymmetric simulations in order to investigate the thrust generation resulting from the interference between the projectile and the blast wave produced by a pulsed laser. The results obtained by our numerical code well agree for the pressure history and the momentum coupling coefficient with the experimental data. In such analysis, it is found that the approximate impulse estimated only by the pressure history at the projectile base is difficult to predict the actual one. Since the shock wave rapidly attenuates in low fill pressure, and the interaction with the projectile almost finishes in the shroud, a highmore » momentum coupling coefficient can be achieved unlike the case of high fill pressure in which the projectile experiences the subsequent negative thrust.« less