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Author Wu, Yue ♦ Sawyer, Jordan C. ♦ Su, Liu ♦ Zhang, Zhili
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY ♦ AIR ♦ BREAKDOWN ♦ DIELECTRIC MATERIALS ♦ ELECTRONS ♦ LASER RADIATION ♦ LASERS ♦ MICROWAVE RADIATION ♦ MULTI-PHOTON PROCESSES ♦ PHOTOIONIZATION ♦ PHOTONS ♦ PRESSURE DEPENDENCE ♦ PULSES ♦ SCATTERING ♦ WAVELENGTHS
Abstract Here we present quantitative measurements of total electron numbers in laser-induced air breakdown at pressures ranging from atmospheric to 40 bar{sub g} by 10 ns and 100 ps laser pulses. A quantifiable definition for the laser-induced breakdown threshold is identified by a sharp increase in the measurable total electron numbers via dielectric-calibrated coherent microwave scattering. For the 10 ns laser pulse, the threshold of laser-induced breakdown in atmospheric air is defined as the total electron number of ∼10{sup 6}. This breakdown threshold decreases with an increase of pressure and laser photon energy (shorter wavelength), which is consistent with the theory of initial multiphoton ionization and subsequent avalanche processes. For the 100 ps laser pulse cases, a clear threshold is not present and only marginal pressure effects can be observed, which is due to the short pulse duration leading to stronger multiphoton ionization and minimal collisional avalanche ionization.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-05-07
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 119
Issue Number 17


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