Ultrafast Space-time and Spectrum-time Resolved Diagnostics of Multicharged Femtosecond Laser Microplasma

Journal Article · Sat Jul 25 00:00:00 EDT 2009 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3204548· OSTI ID:21344334

Garnov, S V; Bukin, V V; Malyutin, A A; Strelkov, V V ^[1]

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1. A. M. Prokhorov General Physics Institute of Russian Academy of Sciences 119991, Vavilov str. 38, Moscow (Russian Federation)

We present the review of the recent experimental studies of fundamental mechanisms of femtosecond laser plasma formation and evolution performed in A. M. Prokhorov General Physics Institute of Russian Academy of Sciences. The main object we dealt with was the micro-sized plasma produced in gases with high intensity (up to 5x10{sup 17} W/cm{sup 2}), tightly focused (to a few microns in diameter) IR and UV femtosecond laser pulses. The main attention in the experiments was paid to the initial stage of microplasma formation and evolution characterized by strong laser-plasma coupling resulting in efficient ionization and heating of the medium, distortion of laser beam, and nonlinear spectral conversion of laser radiation to the continuum and laser harmonics. Using a precise pump-probe micro-interferometric technique the dynamics of plasma was studied with femtosecond time-resolution in a wide density range--from a minimal detectable electron concentration (10{sup 19} cm{sup -3}) to the almost total (down to nuclei) ionization of ions occurred under femtosecond excitation. The obtained time-dependences of plasma density were analyzed. It was observed, for the first time, that a characteristic time of femtosecond laser plasma formation in gases considerably (in times) exceeds the duration of the pump laser pulse. This postionization process is attributed to impact ionization of plasma by hot electrons. We compare the results of the experiments with what the developed theory predicts. Using an ultrafast streak-camera-based spectroscopy technique the temporal evolution of microplasma emission and the dynamics of spectral lines formation in UV-visible range were studied with picosecond time-resolution.

• OSTI ID: 21344334
• Journal Information: AIP Conference Proceedings, Vol. 1153, Issue 1; Conference: 2. international symposium on laser-driven relativistic plasmas applied to science, industry and medicine, Kyoto (Japan), 19-23 Jan 2009; Other Information: DOI: 10.1063/1.3204548; (c) 2009 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COMPARATIVE EVALUATIONS
ELECTRON DENSITY
ELECTRONS
EXCITATION
GASES
HARMONICS
IONIZATION
IONS
LASER RADIATION
LASER-PRODUCED PLASMA
NONLINEAR OPTICS
NONLINEAR PROBLEMS
PLASMA DENSITY
PLASMA DIAGNOSTICS
PLASMA PRODUCTION
STREAK CAMERAS
TIME DEPENDENCE
TIME RESOLUTION
CAMERAS
CHARGED PARTICLES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY-LEVEL TRANSITIONS
EVALUATION
FERMIONS
FLUIDS
LEPTONS
OPTICS
OSCILLATIONS
PLASMA
RADIATIONS
RESOLUTION
TIMING PROPERTIES