PRE-IONIZATION CONTROLLED LASER PLASMAS: NONEQUILIBRIUM AND PLASMA LENSING
Abstract
We propose a program to explore the physics of pre-ionization controlled laser induced plasmas in air. We build upon our past work which has shown that the pre-ionization approaches allow tailored plasmas with a wider envelope of conditions compared to those attainable with conventional single-pulse approaches. We examine systems where a first pulse provides preionization (not full breakdown) allowing controlled absorption and plasma formation in the presence of the second pulse. We generally use ultraviolet pulses for pre-ionization, owing to stronger multiphoton ionization, and near-infrared pulses for energy addition. Our research advances the understanding of the basic physics of these systems with a view to supporting multiple Air Force applications including new sources for ignition and/or flow-control of propulsion devices (scramjets, aero-turbines, pulsed detonation engines), for directed energy applications (non-lethal weapons, atmospheric waveguides), and for diagnostics (LIBS and standoff detection of chemical agents). Highlights of past work include showing efficient preionization followed by energy addition, controlling the energy deposition of the pulses to control the plasma-driven gas dynamics in ways that expand ignition windows, and development of a detailed 2-D model including an integrated chemical-optical solver. The proposed program comprises a combined experimental and modeling effort to further investigate the pre-ionization laser plasmas with emphasis on plasma non-equilibrium and plasma-lensing effects to tailor plasma formation in gases and multi-phase flows. Detailed characterization and spatiotemporal tracking of the non-equilibrium (multiple temperature distributions) will provide a step toward controlling plasma chemistry and generating of reactive radical species. The lensing (beam steering) arises due to plasma-induced variation of the refractive-index profile. We will use a chemical-optical solver to investigate means of varying the beam spatial profiles in ways that enhances the energy deposition and plasma kernel formation. The proposed research will provide important advances in the physics of laser induced plasmas and pre-ionization.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 20, 2023
- Source ID
- FA95502210424
Entities
People
- Azer Yalin
Organizations
- Air Force Office of Scientific Research
- Colorado State University
- United States Air Force