IN RECENT EXPLOSIVE TESTS AT THE DOE/NNSA, CLOUDS OF MICROMETER CERIUM PARTICLES HAVE BEEN OBSERVED EJECTED INTO HYDROGEN ENVIRONMENTS WHERE THEY REACT ON MICROSECOND TIMESCALES. CURRENT MODELS OF THE FUNDAMENTAL CERIUM HYDRIDE PARTICLE REACTIONS ARE HIGHLY SPECULATIVE, AND PREDICTED RADIATIVE TEMPERATURES DO NOT MATCH MEASURED VALUES. THIS PROJECT PROPOSES TO CLOSE KNOWLEDGE GAPS VIA THE FIRST-EVER EXPERIMENTAL OBSERVATIONS OF INDIVIDUAL CERIUM PARTICLES REACTING IN HYDROGEN GAS. SPATIALLY FIXED PARTICLES WILL BE INVESTIGATED WITH UNIQUE ELECTRODYNAMIC LEVITATION AND JOULE HEATED WIRE CONFIGURATIONS. EVOLVING PARTICLE SIZES AND HYDRIDE CRUST DYNAMICS WILL BE CAPTURED WITH MHZ RATE MICROSCOPY. CONCURRENTLY, PARTICLE TEMPERATURES WILL BE QUANTIFIED WITH MULTI-SPECTRAL PYROMETRY, AND GAS-PHASE THERMAL BOUNDARY LAYERS WILL BE MEASURED WITH ADVANCED LASER SPECTROSCOPIC DIAGNOSTICS. THE COMBINED EXPERIMENTAL RESULTS WILL BE USED TO VALIDATE CURRENT MODELS AND DERIVE MODEL IMPROVEMENTS TO CAPTURE OBSERVED EXPERIMENTAL BEHAVIOR.