Experimental study on microwave beaming propulsion using a 1MW-class gyrotron
- Paper number
IAC-05-C4.6.01
- Author
Mr. Yasuhisa Oda, University of Tokyo, Japan
- Coauthor
Mr. Atsushi Kasugai, Japan
- Coauthor
Dr. Kimiya Komurasaki, University of Tokyo, Japan
- Coauthor
Dr. Keishi Sakamoto, Japan
- Coauthor
Dr. Koji Takahashi, Japan
- Year
2005
- Abstract
Microwave beaming propulsion is a new application of atmospheric discharge in a high power microwave beam. Our concept of microwave beaming propulsion is explained as follows: A vehicle focuses the transmitted microwave beam by parabolic reflector and causes breakdown of atmospheric air in the vicinity of the focal point. The induced plasma absorbs the following part of the microwave pulse and expands outwards while generating a shock wave. The shock wave drives impulsive force to the reflector. Microwave pulses are provided repetitively and produce propulsive thrust. Because propulsive energy is provided by a microwave beam transmitted from outside, the vehicle is not necessary to load an energy source on itself. And more the atmospheric air can be utilized as propellant, the vehicle can achieve high payload ratio. Thus, microwave beaming propulsion is expected to realize a remarkably low-cost launch to orbit system.
We conducted a flight experiment of a microwave beaming propulsion using a 1MW-class 170GHz gyrotron developed by Japan Atomic Energy Research Institute. Thruster models were launched vertically and flight trajectories were recorded. The initial velocity was calculated from the trajectory and impulsive thrust estimated. Momentum coupling coefficient C m , defined as a ratio of propulsive impulse to input power, was deduced from measured thrust. C m was over 400N/MW at single pulse test. At flight test with pulse repetition, C m decreased at high frequency pulse repetition.
Plasma development and shock wave propagation inside of the thruster was observed. Plasma generated in the vicinity of focal point propagated at super sonic velocity absorbing microwave. Measured velocity of shock wave propagation was of the same order of the plasma propagation velocity. A model of plasma and shock wave interaction was proposed.
- Abstract document
- Manuscript document
IAC-05-C4.6.01.pdf (🔒 authorized access only).
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