MEC-U: Co-locating LCLS with Kilojoule and High Repetition Rate Petawatt Lasers for Groundbreaking Precision Dynamic Compression and Discovery Plasma Science*

We report on MEC-U, a project to co-locate a state-of-the art laser dynamic compression and high energy density laboratory plasma capability with the Linac Coherent Light Source (LCLS). LCLS was the world's first hard X-ray free electron laser (XFEL), commissioned in 2009 and operating for over a decade as an open-access user facility. Its unprecedented brightness, spectral control and ultrafast pulse duration have made it a transformative capability across many areas of science. Hard X-ray FELs are uniquely suited for high-resolution probing of dynamic compression and high energy density laboratory plasmas driven by high power lasers, allowing time-resolved, first-principles measurement of fundamental state properties at unprecedented accuracy and precision. It is for this purpose that the MEC instrument was built in 2012, and it has had a profound impact in the field but has also inspired calls for more powerful lasers at XFELs. The MEC-U project will construct a new LCLS experimental hall housing a 10 Hz repetition rate 150 J petawatt system that can also be run in nanosecond pulse-shaped mode and a 1 kilojoule nanosecond pulse-shaped system, with additional space set aside for further upgrades. An efficient and versatile target chamber will support experiments using these lasers together with LCLS X-rays at up to 10 Hz, with a separate target area available for laser-only experiments. The presentation will overview scientific opportunities for this new facility and progress towards preliminary design.