Energy transport and photon emission are theoretically investigated in laser-heated foil targets at medium laser irradiance, with use of a numerical model which treats hydrodynamics, ionization, and radiation in a completely self-consistent manner. The radiation model is a detailed, collisional radiative scheme which calculates explicitly the line, recombination, and bremsstrahlung emission in concert with a probabilistic photon transport method. The role of radiation transport in thin-foil targets was studied as a function of target thickness, target-Z, laser intensity, laser wavelength, and laser pulse width. Significant differences were found in the radiation preheat, x-ray conversion efficiency, and broadband frontside emission spectrum, as these parameters were varied. It is also demonstrated that photon emission, absorption, and transport play an important role in the accurate calculation of heat penetration, plasma temperature and density gradients, and ablation-surface–to–critical-surface separation distance, and that radiation can constitute a major energy-loss mechanism even in a low-Z target such as carbon.

• Received 8 January 1985

DOI:https://doi.org/10.1103/PhysRevA.31.3220