High Speed Pulsed Laser Ablation Measurements of Cone-Tip Materials in Realistic Hypersonic Environments

Hypersonic aircraft pose a significant threat to US defenses due to their over-the-horizon strike capabilities. Low altitude flight at hypersonic speeds makes tracking and engagement using kinetic weapons exceedingly difficult and expensive, necessitating the use of directed energy defense measures providing speed-of-light engagement at a much lower cost. RF and microwave sources are a potential solution, although the plasma boundary layer established during hypersonic flight shields RF/MW frequencies used in deployed systems. An alternative solution is continuous wave lasers, which are limited in their utility since hypersonic cone tip materials are highly resistant against thermal damage mechanisms. Additionally, the hypersonic boundary layer enclosing a projectile serves to remove and redistribute heat, further limiting the effectiveness of high average power lasers. In contrast, high peak power lasers are effective against hypersonic materials. They produce nonlinear ablation mechanisms that remove material nearly instantly. Existing pulsed laser technology at Spectral Energies is suitable for generating and studying rapid ablation processes of exotic hypersonic materials at relevant laser energies (kJ level). This laser technology base will be paired with SE’s expertise performing flow diagnostics in several hypersonic wind tunnel facilities reaching Mach 10 flow speeds. The combination of DE-level pulsed sources, access to hypersonic facilities, and an industry leading diagnostic suite is required to properly evaluate the effectiveness of pulsed laser sources against emerging hypersonic threats.