Hot deuteron generation and neutron production in deuterated nanowire array irradiated at relativistic intensity

Irradiation of arrays of aligned high aspect ratio nanowires with high contrast femtosecond laser pulses of relativistic intensity was recently shown to volumetrically heat near solid density plasmas to multi-KeV energy [1]. Using aligned arrays of deuterated polyethylene nanowires (CD$_{\mathrm{2}})$ irradiated at laser intensities of up to $_{\mathrm{\thinspace }}$1 x 10$^{\mathrm{20\thinspace }}$ W/cm$^{\mathrm{2}}$ we are able to generate near solid density plasmas in which the tail of the deuteron distribution was measured to reach energies of up to 3 MeV, in agreement with particle-in-cell simulations. Comparative measurements conducted using flat CD$_{\mathrm{2}}$ targets irradiated by the same laser pulses show the maximum deuteron energies are sub-MeV. We also observed a 100x increase in the number of neutrons produced as compared to flat CD$_{\mathrm{2}}$ targets irradiated at the same conditions, with the highest yield shots producing above 10$^{\mathrm{6}}$ neutrons per Joule of laser energy. [1] M. A. Purvis, V. N. Shlyaptsev, R. Hollinger, C. Bargsten, A. Pukhov, A. Prieto, Y. Wang, B. Luther, L. Yin, S. Wang, and J. J. Rocca, Nature Photonics \textbf{7}, 769, (2013).