X-RAY HEATING, TEMPERATURE AND IONIZATION OF PHOTOIONIZED PLASMAS THE OBJECTIVE OF THIS PROJECT IS TO INVESTIGATE EXPERIMENTALLY AND THEORETICALLY THE X-RAY HEATING, ELECTRON TEMPERATURE AND CHARGED STATE DISTRIBUTION OF LABORATORY PHOTOIONIZED PLASMAS RELEVANT TO ASTROPHYSICS. THE EXPERIMENTS WILL BE PERFORMED USING THREE PREVIOUSLY ESTABLISHED PLATFORMS: (1) A GAS JET DRIVEN BY THE X-RAY FLUX PRODUCED AT THE COLLAPSE OF A WIRE-ARRAY Z-PINCH IN THE 1MA ZEBRA PULSED POWER GENERATOR, (2) AN EXPANDING TAMPED-FOIL SAMPLE DRIVEN BY THE X-RAY FLUX PRODUCED BY AN ARRANGEMENT OF COPPER HOHLRAUMS IRRADIATED BY THE OMEGA EP LASER, AND (3) AN EXPANDING TAMPED-IRON FOIL SAMPLE DRIVEN BY THE X-RAY FLUX PRODUCED BY AN ARRANGEMENT OF GOLD HOHLRAUMS AT THE NATIONAL IGNITION FACILITY. ALL THESE EXPERIMENTS PERMIT TO PRODUCE AND SUSTAIN PHOTOIONIZED PLASMAS IN STEADY-STATE CONDITIONS THUS AVOIDING DATA INTERPRETATION ISSUES DUE TO TRANSIENT EFFECTS. THESE EXPERIMENTS WILL BE DIAGNOSED WITH EMISSION AND ABSORPTION X-RAY SPECTROSCOPY AS WELL AS OPTICAL LASER DIAGNOSTICS.