S. Feldman

Selective deuteron production using target normal sheath acceleration

We report on the first successful demonstration of selective deuteron acceleration by the target normal sheath acceleration mechanism in which the normally overwhelming proton and carbon ion contaminant signals are suppressed by orders of magnitude relative to the deuteron signal. The deuterium ions originated from a layer of heavy ice that was deposited on to the rear surface of a 500 nm thick membrane of Si3N4 and Al. Our data show that the measured spectrum of ions produced by heavy ice targets is comprised of ∼99% deuterium ions. With a laser pulse of approximately 0.5 J, 120 fs duration, and ∼5×1018Wcm-2 mean intensity, the maximum recorded deuterium ion energy and yield normal to the target rear surface were 3.5 MeV and 1.2×1012sr−1, respectively.

Measurement of the equation of state of solid-density copper heated with laser-accelerated protons

We present equation of state (EOS) measurements of solid-density copper heated to 5-10 eV. A copper sample was heated isochorically by hydrogen ions accelerated from an adjacent foil by a high intensity pulsed laser, and probed optically. The measured temperature and expansion are compared against simulations using the most up-to-date wide range EOS tables available.

Double shock front formation in cylindrical radiative blast waves produced by laser irradiation of krypton gas

Radiative blast waves were created by irradiating a krypton cluster source from a supersonic jet with a high intensity femtosecond laser pulse. It was found that the radiation from the shock surface is absorbed in the optically thick upstream medium creating a radiative heat wave that travels supersonically ahead of the main shock. As the blast wave propagates into the heated medium, it slows and loses energy, and the radiative heat wave also slows down. When the radiative heat wave slows down to the transonic regime, a secondary shock in the ionization precursor is produced. This paper presents experimental data characterizing both the initial and secondary shocks and numerical simulations to analyze the double-shock dynamics.

High Repetition Rate kJ-class Nanosecond to Femtosecond Lasers

Using novel liquid cooled slab laser amplifier technology we have developed laser systems capable of amplifying nanosecond laser pulses to energy of ~1 kJ at repetition rate up to 0.1 Hz. The design and performance of these liquid cooled amplifiers at 18 cm aperture will be described along with plans to scale this technology to larger aperture and higher repetition rate.