Heating, Ionization and Magnetic Instability in Short Pulse High Power Laser-Solid Target Interactions

During short pulse high power laser solid matter interactions, a significant fraction of laser pulse energy is absorbed to generate an intense beam of fast electrons with relativistic kinetic energies near the critical density surface. The transport of the intense fast beam into the solid target is of fundamental importance to many complex dynamics such as plasma oscillation, heating, ionization, instability, electric field and magnetic field generation, photon emission and so on. In the talk, we will present the ultrafast plasma dynamics for ion heating in buried layer targets[1], bulk electron heating [2], collisional ionization [2,3], transport instability and quasistatic magnetic generation from PIC simulations. In order to connect the complex plasma dynamics seen in PIC simulations with experiments, we will discuss the role of insitu synthetic diagnostics that mimic experimental diagnostics. As one key example we propose to use XRay Free Electron Lasers for probing the density modulations in the bulk target by small angle Xray scattering which allows for femtosecond and nanometer resolution of transient plasma processes. We will also discuss the feasibility to probe selfgenerated MegaGauss magnetic fields associated with the transport instability of the laser accelerated hot electrons using Faraday rotation method. With these techniques, probing fundamental plasma properties will allow for direct comparison to simulations, challenging state of the art theoretical modeling of collisions, ionizations and so on. [1] L. G. Huang, M. Bussmann, T. Kluge, A. L. Lei, W. Yu, and T. E. Cowan, Phys. Plasmas 20, 093109 (2013). [2] L. G. Huang, T. Kluge, and T. E. Cowan, Phys. Plasmas 23, 063112 (2016). [3] T. Kluge, M. Bussmann, H.K.Chung, C. Gutt, L. G. Huang, M. Zacharias, U. Schramm, and T. E. Cowan, Phys.Plasmas 23, 033103 (2016).