Laser Plasma Instability (LPI) Driven Light Scattering Measurements with Nike KrF Laser*

With the short wavelength (248 $nm$), large bandwidth ($1\sim2 $ $THz$), and ISI beam smoothing, Nike KrF laser is expected to have higher LPI thresholds than observed at other laser facilities. Previous measurements using the Nike laser [J. L. Weaver et al, Phys. Plasmas 14, 056316 (2007)] showed no LPI evidence from CH targets up to $I\sim2\times10^{15}$ $W/cm^{2}$. For further experiments to detect LPI excitation, Nike capabilities have been extended to achieve higher laser intensities by tighter beam focusing and higher power pulses. This talk will present results of a recent LPI experiment with the extended Nike capabilities focusing on light emission data in spectral ranges relevant to the Raman (SRS) and Two-Plasmon Decay (TPD) instabilities. The primary diagnostics were time-resolved spectrometers with an absolute-intensity-calibrated photodiode array in $(0.4\sim0.8)\omega_0$ and a streak camera near $0.5\omega_0$. The measurements were conducted at laser intensities of $10^{15}\sim10^{16}$ $W/cm^{2}$ on planar targets of CH solids and RF foams.