Experimental Demonstration of Magnetic Thrust Chamber for a Laser Fusion Rocket

Abstract

In order to validate the concept of a magnetic thrust chamber for laser fusion rockets, the interaction between laser-produced plasma and the magnetic field produced by a permanent magnet/coil is investigated. Time variation in magnetic flux density in the magnetic thrust chamber was observed by means of several loop probes. The magnetic flux density at the midpoint between the permanent magnet and the target was found to decrease, approaching zero at 50 ns after laser ignition; it then recovers to its initial value after 1 μs. This result demonstrates the concept of the magnetic thrust chamber; the diamagnetic cavity was observed. The impulse bit of the magnetic thrust chamber is estimated from the time variation of the magnetic flux density; it is 0.6 μNs at a laser energy of 0.6 J and laser pulse duration of 2 ns. The estimated impulse bit is in good agreement (order of magnitude) with that measured using a pendulum thrust stand.