Generation of narrow energy spread ion beams via collisionless shock waves using ultra-intense 1 um wavelength laser systems

In this work, we report on electrostatic collisionless shock wave acceleration experiments that produced proton beams with peak energies between 10-17.5 MeV, with narrow energy spreads between $\Delta $ E / E of 10-20 {\%}, and with a total number of protons in these peaks of 1e7-1e8.~ These beams of ions were created by driving an electrostatic collisionless shock wave in a tailored near critical density plasma target using the ultra-intense ps duration Titan laser that operates at a wavelength of 1 um.~ The near critical density target was produced through the ablation of an initially 0.5 um thick Mylar foil with a separate low intensity laser. ~ A narrow energy spread distribution of carbon / oxygen ions with a similar velocity to the accelerated proton distribution, consistent with the reflection and acceleration of ions from an electrostatic field, was also observed.