Development of noncontact suspension technique of a pellet for laser fusion

In laser fusion experiments, for uniform irradiation, a stalk that supports a pellet affects uniformity. In our laboratory, we are studying non-contact suspension technique in the following four directions. First, we are introducing Magnetically Suspended Pellet (MSP) of a Ni coated Glass Micro Balloon (Ni-GMB) in high vacuum. Small external disturbances, however, cause it to vibrate horizontally. We have shown the effectiveness of active damping by use of optical forces. As another new method, we propose stabilization by rotation of Ni-GMB itself. Secondly, electric suspension system for a transparent GMB of laser fusion has been studied using RE-QTDQ (ring electrode quasi three dimensional quadrupole). Optical forces effect in electric suspension is experimentally confirmed. Thirdly, we are studying fundamentals of acoustic levitation. Lastly, a Pulsed Laser Deposition (PLD) enables us to have a uniform Ni coat over a laser fusion pellet. In heat-resister vacuum deposition method, we find gravitational effect of droplets and threshold distance of clean film. We have shown the pattern projection method is simple and effective to measure a PMB thickness.