Comparison between radiation-preheated and conventional shock-driven direct-drive targets for KrF lasers

A radiation-preheated direct-drive target is examined where the fuel isentrope is varied by changing the high-Z dopant concentration in the ablator. As usual, the growth of the Rayleigh–Taylor instability as determined by a one-dimensional stability analysis can be decreased when the isentrope increases. The target performance is found to be quite similar to previously designed targets where the ablator and fuel isentropes were increased via an initial shock. However, the gain decreases slightly more because some of the laser input energy is carried away as radiation and does not contribute to the kinetic motion of the target on its way inward. This design adds to the options available for high-gain targets that are stable enough against hydrodynamic instability.