2波長マッハツェンダー干渉法を用いたレーザー支持爆轟波構造の解明

摘要

To investigate the internal structure of LSD waves, electron density distribution ne was measured by two-wavelength Mach-Zehnder interferometer and electron temperature Te was by emission spectroscopy. As a result, peak values of ne and Te were about 2 x 1024 m~3 and 30,000 K, respectively. Based on the measured properties, laser absorption coefficient was calculated. It showed that incident laser energy was perfectly absorbed in a layer much thinner than a plasma layer, situation of which was not predicted by the conventional LSD model. Measured ne at the shock front was not zero while LSD was supported. This suggested that the precursor electrons exist ahead of the shock wave.%大気吸い込み式RP（Repetitively Pulsed）レーザー推rn進1-5）は，地上から繰り返しパルスレーザーにより供給さrnれたエネルギーを推進に用いる推進機関である．機体下部rnの放物面鏡でビームを集光して焦点付近にプラズマを誘起rnさせると，気体の急激な膨張により爆風波が生じる．その際rnにレーザー支持爆轟（Laser Supported Detonation；LSD）rn波が生じ，衝撃波は強められ，ビームエネルギーを吸収しrn衝撃波のエンタルピに変換される．