Spatial and temporal characteristics of laser-induced air plasma

Nobuyuki Kawahara, Eiji Tomita, Takashi Nakayama, Yuji Ikeda, Atsushi Nishiyama

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

We investigated laser-induced breakdown in air using a framing intensified charged coupled device (ICCD) camera and fiber-coupled ICCD spectrometer with Cassegrain optics. Localized breakdown plasma was generated from the laser pulse of a Q-switched Nd:YAG laser with a wavelength of 532 nm, and we obtained the temporal evolution of the air plasma shape, size, and location. During the initial stage, breakdown occurred on the laser side of the focal point due to the absorption of the pulse energy. Then, the breakdown plasma generally propagated in the direction of the laser. The propagation speed of the laserinduced breakdown was estimated to exceed 10 km/s during the initial stage of breakdown. The high spatial resolution of the Cassegrain optics system was used to observe different ionization levels in the breakdown plasma. Continuous background due to ionization appeared during the earliest stage of plasma development. The intensity of this background decreased after 100 ns and the atomic emission spectra of nitrogen (NI, 745 nm), oxygen (OI, 777 and 821 nm) and hydrogen (HI, 655.5 nm) appeared 200 ns after the laser pulse. The plasma temperature could be evaluated using the two-line ratio between the OI emission line intensities. We determined that simultaneous measurement using both the framing ICCD camera and an ICCD spectrometer with Cassegrain optics could be very useful for investigating the breakdown of laser-induced air plasma.

Original languageEnglish
Title of host publicationCollection of Technical Papers - 44th AIAA Aerospace Sciences Meeting
Pages17586-17595
Number of pages10
Volume23
Publication statusPublished - 2006
Event44th AIAA Aerospace Sciences Meeting 2006 - Reno, NV, United States
Duration: Jan 9 2006Jan 12 2006

Other

Other44th AIAA Aerospace Sciences Meeting 2006
CountryUnited States
CityReno, NV
Period1/9/061/12/06

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ASJC Scopus subject areas

  • Space and Planetary Science
  • Aerospace Engineering

Cite this

Kawahara, N., Tomita, E., Nakayama, T., Ikeda, Y., & Nishiyama, A. (2006). Spatial and temporal characteristics of laser-induced air plasma. In Collection of Technical Papers - 44th AIAA Aerospace Sciences Meeting (Vol. 23, pp. 17586-17595)