Multifacet Role of Relativistic Transparency in Laser-plasma Interactions

David J. Stark, University of Texas, Austin
January 22, 1:30 - 2:30pm, EBUII 479

Abstract:  

The nature of how light interacts with plasma is fundamentally altered when the bulk of the electrons become relativistic, resulting in an enhanced trans-parency. In this talk I will present three novel aspects of this phenomenon: 1) the polarization-dependent critical threshold in an anisotropic distribution; 2) the extended pulse propagation through an overcritical target, facilitating the generation of a collimated, high-yield multi-MeV photon beam; and 3) the shaping of the critical surface in a plasma mirror leading to the focusing of a laser beam. Using fully self-consistent 2D and 3D particle-in-cell simulations to demonstrate these features, I show how relativistic transparency depends both on how the energy is partitioned between di_erent degrees of freedom and on the amplitude of the laser pulse itself.