Separation of d and t ions in exploding pusher simulations

It is shown by means of hybrid particle-in-cell simulations that convergence of the spherical shock wave that propagates through the inner gas of an exploding pusher experiment is accompanied by separation of d and t ions across the shock front. Deuterons run ahead of the tritons and reach the center $\sim $100 ps before the tritons. The rising edge of the DD and TT fusion rate is also temporally separated by the same amount, which should be a measurable observable in experiments and would be a direct proof of the ``stratification conjecture'' [1,2]. Moreover, decoupling of the d and t ions, in terms of both density and temperature, leads to a degradation of the DT fusion yield around shock flash. This suggests the necessity of including multiple-species effects in ICF simulations. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by LDRD 11-ERD-075. \\[4pt] [1] P. Amendt et al, Phys. Plasmas 18, 056308 (2011).\\[0pt] [2] D. T. Casey, et al., PRL 108, 075002 (2012)