Non-contact suspension techniques for pellets in laser fusion experiments

Abstract

A Ni-coated plastic micro balloon (Ni-PMB) suspended in non-contact fashion is reported to achieve uniform irradiation of a laser fusion target. The first section presents the development of magnetic suspension system ‘MINO-2’ for laser fusion experiment; MINO-2 demonstrates magnetic suspension of a 1 mm diameter, Ni-PMB at <1.0×10 −3 Pa with the vertical oscillation amplitude <5 μm; We successfully demonstrated a laser shot experiment in MINO-2. The second section describes the method of active damping of horizontal oscillation using optical forces, in which the initial vibration 27.3 μm became 1.8 μm in 3.7 s. In the third section, a pulsed current method for laser physical deposition is proposed where we find the droplets decrease. Finally, another method of non-contact technique is proposed where an electrodynamic suspension is used as one of non-contact suspension methods. The minimum vibrating amplitude less than observable resolution is attained experimentally at three voltages and at the precise position of the ring electrode in the air.