1. Resonant- and avalanche-ionization amplification of laser-induced plasma in air.
- Author
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Yue Wu, Zhili Zhang, Naibo Jiang, Sukesh Roy, and Gord, James R.
- Subjects
LASER plasmas ,ELECTRON density ,WAVE amplification ,OXYGEN ,NITROGEN ,IONIZATION (Atomic physics) - Abstract
Amplification of laser-induced plasma in air is demonstrated utilizing resonant laser ionization and avalanche ionization. Molecular oxygen in air is ionized by a low-energy laser pulse employing (2 + 1) resonance-enhanced multi-photon ionization (REMPI) to generate seed electrons. Subsequent avalanche ionization of molecular oxygen and nitrogen significantly amplifies the laser-induced plasma. In this plasma-amplification effect, three-body attachments to molecular oxygen dominate the electron-generation and -loss processes, while either nitrogen or argon acts as the third body with low electron affinity. Contour maps of the electron density within the plasma obtained in O
2 / N2 and O2 /Ar gas mixtures are provided to show relative degrees of plasma amplification with respect to gas pressure and to verify that the seed electrons generated by O2 2 + 1 REMPI are selectively amplified by avalanche ionization of molecular nitrogen in a relatively low-pressure condition (≤100 Torr). Such plasma amplification occurring in air could be useful in aerospace applications at high altitude [ABSTRACT FROM AUTHOR]- Published
- 2014
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