Current and future dynamic compression capabilities of the MEC endstation at LCLS*

Free Electron Lasers (FEL), the 4^th generation of lights sources available to users since more than a decade, has been transformational for the High Energy Density Science community. The X-ray sources with high peak brightness deliver photon energies up to about 25 keV in the fundamental, simultaneously with pulse energies in the mJ range and fs pulse duration, providing  an ideal source to probe single shot high energy events with precision. Consequently, most of the hard X-ray FEL facilities couple the FEL with high energy optical laser systems into dedicated experimental platforms allowing the shock compression community to produce high quality data set of various compressed materials at pressure up to several Mbar.

Here we present the experimental capabilities for dynamic compression of the Matter in Extreme Conditions (MEC) endstation of the Linac Coherent Light Source (LCLS) at SLAC. The primary source for this class of experiments is a long pulse laser system (>60J, 10ns, 1 shot per 7 minutes). A short pulse laser system (1J, 40 fs, 5Hz) for high intensity laser-matter interaction experiments is also available. We will detail the performances of the laser system and experimental platforms dedicated to dynamic compression and currently available to the user community. Finally, we will discuss about the status of the DOE-FES-led project to upgrade MEC with kJ long pulse and PW-class optical laser systems, all coupled to the LCLS FEL beam. The targeted mission space of this upgrade is to tackle grand challenge questions in the areas of relativistic laser plasmas, nonlinear optics of plasmas, HED hydrodynamics, magnetized HED plasma physics, and warm dense matter, while also expanding the phase space accessible to the dynamic compression science community, which makes up a large part of the current MEC user base.