Chemistry and Dynamics of Pre-Ionization Controlled Laser Plasmas
Abstract
We propose a program to explore the physics of pre-ionization controlled laser induced plasmasin air. Specifically, we examine the use of multiple laser pulses where the first pulse providespre-ionization (not full breakdown) allowing controlled absorption and plasma formation in thepresence of the second pulse. The pulses can have different durations and wavelengths – wegenerally use ultraviolet (UV) pulses for preionization, owing to stronger multiphoton ionization(MPI), and near-infrared (NIR) pulses for energy addition. In comparison to other work in thefield, we can form tailored laser plasmas over a wider envelope of conditions with more controlover parameters including ionization fraction, temperature and energy distribution, activespecies, plasma-driven fluid dynamic conditions, and time-varying index-of-refraction profiles.There are multiple applications of these plasmas towards Air Force interests including providingnew ignition sources for propulsion devices (aero-turbine combustors and scramjets), plasmaformation at larger standoff distances (for non-lethal weapons and diagnostics such as explosivesdetection), atmospheric waveguides for microwave propagation, and potentially as plasmaactuators for flow control. The physics and chemistry of the pre-ionization controlled plasmasbrings in new issues relative to commonly studied single-pulse laser plasmas. The proposedresearch will advance the understanding and application of laser induced plasmas by addressinggaps in the areas of understanding the relevant processes during the ionization stage, theinterplay between chemistry and plasma-driven dynamics in plasma assisted flame kernels, andability to control the refractive-index profile to optimize plasma parameters and allow standoffplasma formation and detection.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 30, 2018
- Source ID
- FA95501810239
Entities
People
- Azer Yalin
Organizations
- Air Force Office of Scientific Research
- Colorado State University
- United States Air Force