Demonstrated Efficient Quasi-Monoenergetic Carbon-Ion Beams Approaching Fast Ignition (FI) Requirements

Using massive computer simulations of relativistic laser-plasma interactions, we have identified a self-organizing scheme that exploits persisting self-generated plasma electric ($\sim $TV/m) and magnetic ($\sim $10$^{4}$ Tesla) fields to reduce the ion energy spread of intense laser-driven ion beams after the laser exits the plasma [1]. Consistent with the scheme, we have demonstrated on the LANL Trident laser carbon-ion beams with narrow spectral peaks at 220 MeV, with high conversion efficiency ($\approx $ 5{\%}) [1]. These parameters are within a factor of 2 of FI requirements [2]. The remaining gap may be bridged by increasing the laser intensity by a factor of 4, according to our data [1]. We also discuss how this beam may be focused, to address the remaining requirement for FI, besides the total laser energy. \\[4pt] [1] S. Palaniyappan, et al$.$, \textit{Efficient quasi-monoenergetic ion beams up to 18 MeV/nucleon via self-generated plasma fields in relativistic laser plasmas, arXiv}:1506.07548v1; S. Palaniyappan, et al., this conference\\[0pt] [2] J.C. Fern\'{a}ndez, et al., \textit{Fast ignition with laser-driven proton and ion beams.} Nuclear Fusion, \textbf{54}(5), 054006 (2014)