Chapter 173 - Temperature effects on formation of a uniform layer of isotopes inside a cryogenic ICF target

Abstract

This chapter investigates the steady-state motion of a gas bubble inside a non-isothermal, spherical, liquid filled cryogenic target by taking into account the effects of gravity, the thermally induced gradient of the gas–liquid interfacial tension, and the finite size of the liquid container. The steady-state migration velocity of a gas bubble located at the center of a spherical shell has been calculated by considering the combined effect of gravity, interfacial tension gradient, and the finite size of the shell. An analytical expression for the temperature gradient that will sustain a stationary bubble at the center of the spherical shell has been derived. Also a calculating function relation about liquid H2 thickness of cryogenic target is proposed using the mass conservation in cryogenic target. The analytic method for the model is also fit for the D2, T2 or the mixture of the D-T. The net result is an expression for the temperature gradient at the target exterior, which will sustain a uniform liquid layer of hydrogen isotopes inside an ICF target. A simple model is established on the basis of the calculation and analysis.