Seminář ÚFE: I. Adamovich

Laser Diagnostics for Measurements of Electric Field and Excited Metastable Species in Nonequilibrium Plasmas and Reacting Flows

Dr. Igor V. Adamovich je profesorem na Ohio State University (Department of Mechanical and Aerospace Engineering).
Jeho výzkumné aktivity zahrnují:

  • Kinetics of gases, plasmas, and liquids at extreme thermodynamic disequilibrium
  • Molecular energy transfer and nonequilibrium chemical reactions
  • Applications for nonequilibrium hypersonic flows, plasma-assisted combustion, plasma flow control, and molecular gas lasers
  • Laser diagnostics of nonequilibrium flows and plasmas

Abstrakt prednášky:

Non-intrusive laser diagnostic measurements of temporal and spatial distributions of electric field and the number densities of excited metastable species in nonequilibrium plasmas are essential for the development of engineering applications such as plasma flow control, plasma-assisted combustion, plasma materials processing, and plasma medicine. This talk presents an overview of recent electric field and species measurements in ns pulse discharge plasmas, Electric Field Induced Second Harmonic (EFISH) generation, Cavity Ring Down Spectroscopy (CRDS), and Tunable Diode Laser Absorption Spectroscopy (TDLAS). EFISH has been used to measure the electric field in dielectric barrier discharge plasma flow actuators, atmospheric pressure flames enhanced by transient plasmas, ionization waves and streamers, and atmospheric pressure plasma jets. Electric field vector components are isolated by monitoring signals with different polarizations, and absolute calibration is done by measuring a known Laplacian field. Absolute time-resolved populations of N2 (A3Σu+) excited electronic state, which is a major precursor of O atoms and NO in air plasmas, as well as H atoms and other radical species in fuel-air plasmas, are measured in a repetitive ns pulse discharge and the afterglow in nitrogen. Two complementary techniques are used for these measurements, CRDS and single-pass TDLAS. The results demonstrate considerable potential of laser diagnostic techniques for characterization of high-pressure nonequilibrium plasmas, where they provide quantitative insight into the kinetics of ionization, charge transport, molecular energy transfer, energy thermalization rate, and plasma chemical reactions.

Více info:

Pozvánka v pdf.

In the week 14.-18.10.2019 Prof. Igor Adamovich (Ohio State University, USA) visited us and gave two lectures on laser diagnostics of non-thermal flows and plasmas. With his support we were also able to setup the EFISH experiment and detect the EFISH signal for non-thermal plasma diagnostics using our nanosecond laser.

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