DURIP Enabling New Measurements of Atom-Atom and Atom-Diatom Collisions Relevant to Hypersonic Plasmas
Abstract
Agency Program Officer:Eric C. Marineau, Ph.D.Office of Naval Research, Department Code 351875 North Randolph Street, Suite 1150Arlington, VA 22203Phone: 703-696-4771eric.c.marineau.civ@us.navy.milHypersonic flows can have temperatures far above 5000 K, with sufficient energy to dissociate nitrogen (N2) and oxygen (O2) molecules in the atmosphere. Once N and O atoms are formed, they can participate in inelastic and reactive collisions with other atoms and molecules in the gas to produce additional atoms and, possibly, atoms in electronically excited states. Energetic collisions of the atoms, especially those involving an electronically excited atom, may result in associative ionization (AI), a process where two atoms combine to form a bond and eject an electron, leaving a diatomicion and a free electron. The formation of NO+, N2+, and O2+ ions, as well as electrons, creates a plasma around a hypersonic vehicle that becomes significant at speeds above Mach 10. Plasma formation leads to communications blackout and other complex phenomena. The PI and Co-PI of this DURIP proposal are currently involved in a Multidisciplinary University Research Initiative (MURI), ONR Grant No. N00014-22-1-2661: #Development of Validated Hypersonic Plasma Kinetics Models Including Atomic Excitation#, with the goal of accurately modeling plasma generation under hypersonic flow conditions. To this end, we are conducting fundamental studies of electronic excitation and ionization in high energy atomic and molecular collisions, using a crossed molecular beams scattering technique that employs a laser-detonation source of hyperthermal atoms and detection of scattered atoms or molecules by resonance enhanced multiphoton ionization (REMPI). We propose here to purchase new molecular beam and laser equipment that will significantly expand our experimental capabilities to study collisions of O and N atoms that lead to electronically-excited atoms or to NO+ ions. The ability to investigate these extremely important plasma-forming reactions on a single-collision level does not exist in the PI#s lab (or anywhere else in the world). The key to this new capability will be the addition of a second hyperthermal molecular beam source, which will enable unprecedented crossed-beams studies of N + O collisions at relative velocities of >11 km s-1, providing sufficient collision energy to create excited-state and ionized products. A new dye-laser system is also proposed to extend the capability of the REMPI laser detection schemes to include all potential excited-state atoms that could be produced. The new equipment will not only helpto ensure a successful MURI but will leave a lasting infrastructure and expertise in the PI#s lab that can be used to continue the study of plasma-generating atomic and molecular collisions, for which there may not be time within the scope of the MURI. The ultimate practical outcome of the near- and long-term scholarly activity enabled by the enhanced molecular beam scattering infrastructure will be accurate predictive models of plasmas in nonequilibrium hypersonic flows and young researchers who will have the training and knowledge to make further advancements in hypersonics and other fields. This Project Summary is publicly releasable.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 08, 2024
- Source ID
- N000142412499
Entities
People
- Timothy K. Minton
Organizations
- Office of Naval Research
- Regents of the University of Colorado
- United States Navy