Optical Measurements of Preheated Polystyrene and Aluminum Layers
Abstract
We present optical measurements of polystyrene and aluminum layers modified by ionizing radiation within a 100-ps time scale. The experiments were performed at the OMEGA Laser Facility using high-energy, 100-ps, 5 x 10^14 W/cm^2 laser pulses impinging onto a 40-μm plastic ablator in order to generate the preheat radiation. Two temporal resolving optical diagnostics, a velocity interferometer for any reflector (VISAR), and a temperature-calibrated streaked optical pyrometer (SOP) measure the change of the optical properties and the temperature increase of samples mounted on the target's back side. Preheating prior to the arrival of a shock front is observed for the aluminum and plastic layers. Within the laser interaction time, a strong absorption and a frequency shift of the optical probe laser reflecting from the samples are measured with VISAR. The SOP measurement indicates temperatures of up to ∼4 eV at the target's back side prior to the shock front arrival. The experimental results are compared to one-dimensional hydrodynamic simulations with the code LILAC. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-92SF19460.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2005
- Bibcode:
- 2005APS..DPPUO1006T