Isochoric plasma sources for laser-plasma interaction studies

Michael Hay, Princeton University

Ongoing and planned experiments considering the backward Raman amplification of laser light or the behavior of Langmuir waves undergoing adiabatic compression are constrained by the diffusing edge of the background plasma mediating these wave processes. Laser light propagating into such a plasma must penetrate a long density gradient that may exhibit a multitude of local resonances with the light. An isochoric plasma with "sharp," well-defined boundaries would reduce the amount of energy diverted into deleterious instabilities. We discuss the salient properties of aerogel and dense aerosol targets that have been designed to meet these criteria. In particular, we will present scaling relations for silica aerogels that define the operating parameter space available to the targets used with a specified laser system. We have also conducted ANSYS FLUENT simulations of dense aerosol formation under aerodynamic focusing. These simulations include momentum coupling between the carrier gas and the particles’ virtual flow field. In addition to the envisioned operating regimes, we will discuss possible plasma lensing configurations using aerosol sheets. We also suggest a suite of diagnostics capable of tracking the formation and subsequent dynamics of these specially-tailored plasmas.

Abstract Author(s): M. J. Hay, E. J. Valeo, and N. J. Fisch