Measurements of Proton Energy Spectra Generated by Ultra Intense Laser Solid Interactions

In this study, we have presented proton energy spectra produced by suchhigh irradiance (1020 w=cm2) lasers interacting with a pre formed plasma in front ofthe target and with solid targets without a pre formed plasma. the effects of the targetthickness and the generated plasma on the maximum energy and proton numbers areassessed. it is observed that experimentally measured maximum proton energy andnumber of protons have a dependence on target thickness and preformed plasma scalelength produced by prepulse laser with the irradiance of  1012 w/cm2. 2d epoch piccode simulation results of the energy spectra of protons are in a good agreement withmeasured experimental results.