A comparison of Hyades and Cretin for modeling laser absorption in underdense plasmas

In a laser produced plasma (LPP), the temperature and density profile and history are determined by the laser energy absorbed by the plasma. Therefore, it is extremely important that the absorption coefficients are calculated accurately when modeling LPP's. We have compared the inverse bremsstrahlung absorption coefficients of the radiation-hydrodynamic code Hyades [1] with the non-LTE atomic kinetics / radiation transfer code Cretin [2]. We found that the absorption coefficients disagree at relatively low electron temperatures (1-100 eV), and then begin to converge as the temperature rises above 100 eV. These discrepancies lead to a dramatically different temperature and density evolution of the LPP.