AVS 61st International Symposium & Exhibition
    Thin Film Tuesday Sessions
       Session TF+SE-TuM

Paper TF+SE-TuM2
The Dynamics of Reactive Foil Ignition after Pulsed Laser Irradiation

Tuesday, November 11, 2014, 8:20 am, Room 305

Session: Energetic Thin Films/Optical Characterization
Presenter: Ryan Murphy, Sandia National Laboratories
Authors: R.D. Murphy, Sandia National Laboratories
R.V. Reeves, Sandia National Laboratories
J.P. McDonald, Dow Corning Corporation
D.P. Adams, Sandia National Laboratories
Correspondent: Click to Email
It has been shown that forced mixing of reactive layers (foils) leads to an exothermic release of energy after initiation of mixing by forced impact or pulsed laser irradiation. In order to understand the ignition of foils initiated by laser irradiation, we study the interaction of laser pulses with Al/Pt multilayer reactive foils prepared by sputter deposition. It will be shown that the single-pulse ignition threshold and dynamics are dependent on the length of the laser pulse as the pulse length is varied from 100 fs to 100 ms. The dependence of the ignition threshold on pulse length is a combination of laser-material interactions such as the size of the heat affected zone, changes in reflectivity with pulse length, and the onset of ablation for ultrafast irradiation. The laser spot size is varied for each pulse length to explore the effects of heat confinement on the ignition threshold. The dynamics of foil ignition is further investigated by imaging ignition and the subsequent reaction with a high-speed camera. Varying the bilayer thickness and laser pulse length is shown to change properties such as mixing, ignition in the solid-state, and the onset time of reaction.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under Contract DE-AC04-94AL85000.