Interaction of high-power flashlamp radiation with an absorbing liquid

An experimental and theoretical investigation was made of the interaction of flashlamp radiation with an absorbing liquid. The experimental conditions corresponded to liquid cooling of flashlamps used for laser pumping. Such special effects in the liquid as a phase transition and a supercritical state were observed in the liquid. A method was developed for obtaining an analytic solution of the nonlinear optothermodynamic problem with an arbitrary equation of state of the liquid. The method was used to calculate the fields of thermodynamic variables in a liquid based on ethanol; an empirical enthalpy-pressure equation of state of ethanol was used in the calculations. A study was made of the mechanisms responsible for the heating of the liquid and the possibility of its boiling was considered allowing for the actual form of the curve bounding the phase volume of the system in the state diagram. The pressure developed in the liquid was measured by means of piezoelectric transducers, which were practically insensitive to the flashlamp radiation and were damped in respect of extraneous acoustic signals. The dependences of the pressure on the parameters of the problem were determined experimentally and found to be in agreement with the calculated curves.