Creation of Si Warm Dense Matter using an intense proton beam by the OMEGA-EP short pulse laser and simulated with 2D particle-in-cell*

The dual OMEGA-EP short-pulse lasers were used to heat a thin Si wafer to the warm dense matter (WDM) regime and measure its temperature. The first beam (10$^{\mathrm{18}}$ W/cm$^{\mathrm{2}}$, 10 ps) irradiated a CH hemispherical cap, subsequently accelerating energetic protons and ions to heat the Si face-on. The second beam (10$^{\mathrm{18}}$ W/cm$^{\mathrm{2}}$, 5 ps) irradiated an adjacent Zn wire tip, generating an x-ray backlighting spectrum which passed through the Si hot spot and into a multipurpose spectrometer (MSPEC) to diagnose the instantaneous Si temperature at delays spanning 200 ps. Modeling predicts that the Si remains \textgreater 30 eV and \textgreater 10{\%} solid density during this time window. We present the proton energy spectra measurements from Radiochromic film and a Thomson Parabola which are used as input to simulate the temperature evolution of the Si via the 2D particle-in-cell code LSP. We show the simulation results and compare with temperature measurements from MSPEC.