At the frontier of plasma physics and technology are applications of
laser-generated plasmas to laboratory simulations of astrophysical
phenomena and to industrial processing. This article presents work at
the Naval Research Laboratory in both of these areas. We show how laser
plasmas are used to measure a blast wave corrugation overstability
important in astrophysics. Detailed atomic physics calculations of
radiative cooling within the blast front are used to develop a
criterion of the existence of the overstability and are used to explain
the experimental results. The criterion depends on quantities such as
element abundances, densities, temperatures, and blast wave
velocities—quantities which can be measured
spectroscopically—and therefore used to infer whether
astrophysical blast wave nonuniformities are the result of this
instability. In other experiments, high-velocity jets are formed in the
laboratory using miniature hollow cones. Jets produced by these cones
are used to study the physics of jets occurring in supernovae and in
star-forming accretion disks. In industrial semiconductor processing,
annealing, that is, removing crystal damage and electrically activating
the semiconductor, is a critical step. Industrial annealing techniques
most often utilize heat generated by an oven, flash lamps, or a
low-power laser. During such heating dopants within the semiconductor
lattice diffuse and spread. This degrades the performance of circuits
in which the individual circuit elements are very close to each other.
We are developing an annealing technique in which shock or sound waves
generated by a laser plasma are used to anneal the semiconductor. We
have demonstrated that the method works over small areas and that it
does not lead to significant dopant diffusion.