Impact of fill tube perturbation on implosion experiments conducted with high density carbon ablators*

At stagnation, all implosion experiments conducted with a high density carbon (HDC) ablator exhibit signatures of fill tube induced mix.  This perturbation could potentially be a significant cause of performance degradation. This talk will discuss the impact that the fill tube perturbation has on state of the reacting plasma and on integrated performance. The changes in the observed fill tube perturbation size, temperature and radiative loss as well as the overall integrated performance between experiments where the initial fill tube diameter was varied will be examined.  Additionally, the observed fill tube dynamics and implosion performance will be compared to detailed radiation hydrodynamic calculations that include a fill tube perturbation.  Using radiation hydrodynamic simulations, the relative impact on performance from enhanced radiative losses, conduction losses, heat capacity, and shell rho r nonuniformity that arise from the fill tube perturbation will be discussed.