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Title: Plasma filamentation and shock wave enhancement in microwave rockets by combining low-frequency microwaves with external magnetic field

Abstract

A filamentary plasma is reproduced based on a fully kinetic model of electron and ion transports coupled with electromagnetic wave propagation. The discharge plasma transits from discrete to diffusive patterns at a 110-GHz breakdown, with decrease in the ambient pressure, because of the rapid electron diffusion that occurs during an increase in the propagation speed of the ionization front. A discrete plasma is obtained at low pressures when a low-frequency microwave is irradiated because the ionization process becomes more dominant than the electron diffusion, when the electrons are effectively heated by the low-frequency microwave. The propagation speed of the plasma increases with decrease in the incident microwave frequency because of the higher ionization frequency and faster plasma diffusion resulting from the increase in the energy-absorption rate. An external magnetic field is applied to the breakdown volume, which induces plasma filamentation at lower pressures because the electron diffusion is suppressed by the magnetic field. The thrust performance of a microwave rocket is improved by the magnetic fields corresponding to the electron cyclotron resonance (ECR) and its higher-harmonic heating, because slower propagation of the ionization front and larger energy-absorption rates are obtained at lower pressures. It would be advantageous if the fundamentalmore » mode of ECR heating is coupled with a lower frequency microwave instead of combining the higher-harmonic ECR heating with the higher frequency microwave. This can improve the thrust performance with smaller magnetic fields even if the propagation speed increases because of the decrease in the incident microwave frequency.« less

Authors:
 [1];  [2]
  1. Department of Aeronautics and Astronautics, The University of Tokyo, Bunkyo-ku 113-8656 (Japan)
  2. Department of Aerospace Engineering, Tohoku University, Sendai 980-8579 (Japan)
Publication Date:
OSTI Identifier:
22597667
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 42 ENGINEERING; BREAKDOWN; CYCLOTRONS; DIFFUSION; ECR HEATING; ELECTRON CYCLOTRON-RESONANCE; ELECTRONS; ENERGY ABSORPTION; GHZ RANGE; IONIZATION; IRRADIATION; MAGNETIC FIELDS; MICROWAVE RADIATION; PLASMA; SHOCK WAVES; VELOCITY; WAVE PROPAGATION

Citation Formats

Takahashi, Masayuki, E-mail: m.takahashi@al.t.u-tokyo.ac.jp, and Ohnishi, Naofumi. Plasma filamentation and shock wave enhancement in microwave rockets by combining low-frequency microwaves with external magnetic field. United States: N. p., 2016. Web. doi:10.1063/1.4960805.
Takahashi, Masayuki, E-mail: m.takahashi@al.t.u-tokyo.ac.jp, & Ohnishi, Naofumi. Plasma filamentation and shock wave enhancement in microwave rockets by combining low-frequency microwaves with external magnetic field. United States. doi:10.1063/1.4960805.
Takahashi, Masayuki, E-mail: m.takahashi@al.t.u-tokyo.ac.jp, and Ohnishi, Naofumi. Sun . "Plasma filamentation and shock wave enhancement in microwave rockets by combining low-frequency microwaves with external magnetic field". United States. doi:10.1063/1.4960805.
@article{osti_22597667,
title = {Plasma filamentation and shock wave enhancement in microwave rockets by combining low-frequency microwaves with external magnetic field},
author = {Takahashi, Masayuki, E-mail: m.takahashi@al.t.u-tokyo.ac.jp and Ohnishi, Naofumi},
abstractNote = {A filamentary plasma is reproduced based on a fully kinetic model of electron and ion transports coupled with electromagnetic wave propagation. The discharge plasma transits from discrete to diffusive patterns at a 110-GHz breakdown, with decrease in the ambient pressure, because of the rapid electron diffusion that occurs during an increase in the propagation speed of the ionization front. A discrete plasma is obtained at low pressures when a low-frequency microwave is irradiated because the ionization process becomes more dominant than the electron diffusion, when the electrons are effectively heated by the low-frequency microwave. The propagation speed of the plasma increases with decrease in the incident microwave frequency because of the higher ionization frequency and faster plasma diffusion resulting from the increase in the energy-absorption rate. An external magnetic field is applied to the breakdown volume, which induces plasma filamentation at lower pressures because the electron diffusion is suppressed by the magnetic field. The thrust performance of a microwave rocket is improved by the magnetic fields corresponding to the electron cyclotron resonance (ECR) and its higher-harmonic heating, because slower propagation of the ionization front and larger energy-absorption rates are obtained at lower pressures. It would be advantageous if the fundamental mode of ECR heating is coupled with a lower frequency microwave instead of combining the higher-harmonic ECR heating with the higher frequency microwave. This can improve the thrust performance with smaller magnetic fields even if the propagation speed increases because of the decrease in the incident microwave frequency.},
doi = {10.1063/1.4960805},
journal = {Journal of Applied Physics},
number = 6,
volume = 120,
place = {United States},
year = {Sun Aug 14 00:00:00 EDT 2016},
month = {Sun Aug 14 00:00:00 EDT 2016}
}