Comparison between direct-drive target designs with radiation preheat and shock heating
Abstract
Radiation preheat has been proposed^1 as a way of reducing the growth of the Rayleigh-Taylor instability by tailoring the ablator adiabat. It was accomplished by coating the target on the outside with a thin high-Z layer. However, the effects of this layer are felt well before the acceleration phase of the implosion when the R-T growth takes place. Another way of including radiation preheat is to add traces of a high-Z material to the ablator. This has the undesired consequences of raising the fuel adiabat, thus lowering the gain. A conventional way of getting the same result is to raise the amplitude of the foot of the laser pulse, creating a stronger shock, resulting in an increase in target stability and a decrease in target performance. The purpose of this work is to make comparisons between these two different concepts of stabilizing a target, one using radiation, the other one using shocks. For targets of similar input energy (around 2.5 MJ), a comparison between these two different types of targets is made trying to match the fuel adiabats just before the burn. The gain and (one-dimensional) stability of these targets will be investigated using our FAST1D design code. 1. S.Bodner, D.Colombant, A.J.Schmitt and M.Klapisch, Phys. Plasmas, 7,2298(2000)
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 2002
- Bibcode:
- 2002APS..DPPKP1142C