Production of extended plasma channels in atmospheric air by amplitude-modulated UV radiation of GARPUN-MTW Ti : sapphire-KrF laser. Part 2. Accumulation of plasma electrons and electric discharge control

Journal Article · Tue Apr 30 04:00:00 EDT 2013 · Quantum Electronics (Woodbury, N.Y.)

DOI:https://doi.org/10.1070/QE2013V043N04ABEH013559· OSTI ID:22113689

Zvorykin, V D; Ionin, Andrei A; Levchenko, A O; Mesyats, Gennadii A; Seleznev, L V; Sinitsyn, D V; Smetanin, Igor V; Sunchugasheva, E S; Ustinovskii, N N; Shutov, A V ^[1]

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1. P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

The problem of the production of extended ({approx}1 m) plasma channels is studied in atmospheric air by amplitude-modulated laser pulses of UV radiation, which are a superposition of a subpicosecond USP train amplified in a regenerative KrF amplifier with an unstable confocal resonator and a quasi-stationary lasing pulse. The USPs possess a high (0.2-0.3 TW) peak power and efficiently ionise oxygen molecules due to multiphoton ionisation, and the quasi-stationary lasing pulse, which has a relatively long duration ({approx}100 ns), maintains the electron density at a level n{sub e} = (3-5) Multiplication-Sign 10{sup 14} cm{sup -3} by suppressing electron attachment to oxygen. Experiments in laser triggering of high-voltage electric discharges suggest that the use of combined pulses results in a significant lowering of the breakdown threshold and enables controlling the discharge trajectory with a higher efficiency in comparison with smooth pulses. It was shown that controlled breakdowns may develop with a delay of tens of microseconds relative to the laser pulse, which is many orders of magnitude greater than the lifetime of free electrons in the laser-induced plasma. We propose a mechanism for this breakdown, which involves speeding-up of the avalanche ionisation of the air by negative molecular oxygen ions with a low electron binding energy ({approx}0.5 eV) and a long lifetime ({approx}1 ms), which are produced upon cessation of the laser pulse. (extreme light fields and their applications)

• OSTI ID: 22113689
• Journal Information: Quantum Electronics (Woodbury, N.Y.), Journal Name: Quantum Electronics (Woodbury, N.Y.) Journal Issue: 4 Vol. 43; ISSN 1063-7818
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
AIR
AMPLITUDES
BINDING ENERGY
ELECTRIC DISCHARGES
ELECTRON ATTACHMENT
ELECTRON DENSITY
IONIZATION
KRYPTON FLUORIDE LASERS
LIFETIME
MOLECULES
MULTI-PHOTON PROCESSES
OXYGEN
OXYGEN IONS
PLASMA
PULSES
RESONATORS
TRAJECTORIES
ULTRAVIOLET RADIATION