Circular polarization effects in ion acceleration from high intensity, short pulse laser interactions*

Experiments were performed to investigate ion acceleration effects from circular polarization from thin targets, using a high contrast, ultra-short laser pulse from the HERCULES laser facility at the Univ. of Michigan. Experiments were performed with $50$ TW, $35$ fs pulses at an intensity of $>10^{21} \; \rm{Wcm}^{-2}$ on $Si_{3}N_{4}$ and Mylar targets of 30 nm to 1 $\mu$m thickness with contrast $<10^{-13}$. Protons with maximum energy 18 MeV and Carbon ions with energies of up to 10 MeV per nucleon were measured. Particle-in-cell simulations demonstrating the acceleration mechanism will be presented as well.