Kinetic Modeling of Ultraintense X-Ray Laser-Matter Interactions
R. Royle, Y. Sentoku, and R.C. Mancini; University of Nevada, Reno
I. Paraschiv; Voss Scientific Inc., New Mexico
T. Johzaki; Hiroshima University, Japan
April 12, 2016, 2:00 - 3:00pm, SERF 383
Abstract: Though hard-x-ray free-electron lasers (XFELs) have only existed since 2009 when the Linac Coherent Light Source (LCLS) at Stanford created its first laser pulse, their capabilities have already had a profound impact on the physical, chemical, and biological sciences. The LCLS can produce extremely short (< 100 fs) millijoule x-ray laser pulses with more than 1012 photons each , making it the brightest x-ray source ever produced in a laboratory by several orders of magnitude, and more than a billion times brighter than synchrotron sources. Such characteristics enable XFELs to create and probe warm and hot dense plasmas of relevance to astrophysical processes in stellar interiors, giant planet cores, galactic nuclei, and x-ray binaries. An LCLS beam can be intensified to ~1020 W/cm2 when focused to submicron spot sizes, making it possible to isochorically heat solid matter well beyond a million degrees (> 100 eV). Such intensities can produce highly ionized plasmas via sequential single-photon absorption and subsequent Auger decay. The fast Auger electrons and photoelectrons further ionize and heat the plasma via collisions. A photoionization model that takes into account the suborbital cross sections and KLL Auger ionization has been developed in a kinetic plasma simulation code, PICLS, that solves the x-ray transport self-consistently . The heating of thin, solid copper targets by short x-ray laser pulses of varying spot size and intensity is studied with the code.
 S. M. Vinko et al., Nature 482, 59-62 (2012).  Y. Sentoku et al., Phys. Rev. E 90, 051102 (2014).
Bio - Ryan Royle: I began my undergraduate studies at UNR as a computer science major and finished with a degree in physics. After attending graduate school at Virginia Tech for a year with the intent of studying particle physics, I realized the reality of working in that field did not appeal to me and left to become a software engineer at International Game Technology in Reno. There I rediscovered my passion for computer programming but was unfulfilled in the gaming industry, and so I left to pursue my graduate studies at UNR in computational plasma physics under the advisement of Dr. Sentoku. Over the past several years I have helped develop and use our group's particle-in-cell code, PICLS, to study various laser--matter interactions, including most recently the interaction of ultraintense x-ray laser pulses with solid density targets. I am now seeking a postdoctoral position that will provide new challenges and enable me to establish my career as a researcher.