Characterization of the fast ionization wave induced by a CO2 laser pulse in argon
Characterization of the fast ionization wave induced by a CO2 laser pulse in argon
复制标题
氩气中 CO2 激光脉冲引起的快电离波的表征
DOI：
10.1063/1.5115815
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发表时间：
2019
影响因子：
3.2
通讯作者：
Shigeru Yokota
中科院分区：
文献类型：
--
作者：
K. Shimamura;Ippei Yokota;Shigeru Yokota
在大气压条件下，用CO_2激光脉冲在1011-1013W/m~2的激光强度下，观察到了激光诱导等离子体击穿后的快速电离波（FIW）现象。根据Raizer的Chapmann-Jouguet爆轰理论，FIW可被区分为“过驱动爆轰”，因为FIW被认为是具有比激光支持爆轰波（LSDW）更高的传播速度的激光吸收波类型。一些报告已经描述了使用固态激光器的FIW的扩展。然而，FIW和LSDW之间的阈值现象并没有从根本上得到理解。本研究利用高速显示与光学发射光谱技术，探讨氩气体中雷射吸收波的跃迁。为了阐明的物理过渡阈值，5 J的CO2脉冲激光，Echelle光谱仪，和增强的CCD相机用于定量调查的等离子体的温度和密度。结果表明，FIW前沿的电子温度为0.7 eV，电子数密度为2.5 × 1023 m − 3。在FIW-LSDW跃迁时，电子温度增加了1 eV，密度降低了2.2 × 1023 m − 3。此外，根据电子温度估算了跃迁阈值和局域热力学平衡的存在，并通过光谱实验得到了密度。
Fast ionization wave (FIW), a postbreakdown phenomenon of laser-induced plasma, is observed for a laser intensity of 1011–1013 W/m2 using the CO2 laser pulse in the atmospheric pressure condition. FIW is distinguishable as “overdriven detonation” according to Raizer's Chapmann-Jouguet detonation theory because FIW is known as the type of laser-absorption wave that has a higher propagation velocity than the laser-supported detonation wave (LSDW). Some reports have described the expansion of FIW using a solid-state laser. Nevertheless, the threshold phenomena between FIW and LSDW are not fundamentally understood. This study used the high-speed visualization and optical emission spectroscopy to investigate the transition of the laser-absorption wave in argon gaseous form. To elucidate the physics of the transition threshold, a 5 J CO2 pulse laser, an Echelle spectrometer, and an intensified CCD camera are used for the quantitative investigation of the plasma temperature and density. Results demonstrate that the FIW front had an electron temperature of 0.7 eV and an electron number density of 2.5 × 1023 m−3. At the FIW–LSDW transition, the electron temperature increased by 1 eV, and the density decreased by 2.2 × 1023 m−3. Besides, the transition threshold and the existence of local-thermodynamic equilibrium were evaluated based on the electron temperature, and the density was obtained from the spectroscopic experiments.
影响因子：
3.2
作者：
K. Shimamura;Keigo Hatai;Koichi Kawamura;A. Fukui;A. Fukuda;Bin Wang-;Toshikazu Yamaguchi;K. Komurasaki;Y. Arakawa
通讯作者：
K. Shimamura;Keigo Hatai;Koichi Kawamura;A. Fukui;A. Fukuda;Bin Wang-;Toshikazu Yamaguchi;K. Komurasaki;Y. Arakawa