Heating a solid isochorically over keV temperature by a multi-picosecond intense laser light

We study isochoric heating via diffusive heat transport driven by multi-picosecond (ps) relativistic laser light. Intense lasers can heat dense plasmas via collisional processes, i.e. resistive heating, drag heating, and/or diffusive heating. Since the laser is stopped at the critical density, the laser produced relativistic electron beam (REB) has been considered as only the candidate to heat the dense plasmas via resistive heating or drag heating. However, the efficiency is low to heat the plasmas volumetrically over keV temperature. By improving the contrast ratio a kJ ps laser, LFEX, realizes the direct interaction of the intense laser light with a solid surface. Because of the direct interaction, the plasma is heated over keV temperature diffusively. Here we study the heating processes using a collisional two-dimensional Particle-in-Cell code, PICLS, and found that the diffusive heat wave reaches to a few micron inside the solid surface in ps time scale. The theoretical scaling of diffusive heating and the laser condition that realizes the diffusive heating during the laser-plasma interaction will be presented. The creation of large volume keV solid plasmas opens a new path to explore the high energy density science.