Melting and shock wave creation in uranium oxide due to Coulomb explosion after a pulsed ionization

ZY Li and D Chen and L Shao, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 358, 65-71 (2015).

DOI: 10.1016/j.nimb.2015.04.077

By means of molecular dynamics simulations, we study the effects of pulsed ionization in uranium oxide (UO2), which occurs when UO2 is bombarded with swift ions or fission fragments. A general formula is developed to predict melting radius under various conditions due to electron stripping and Coulomb explosion (CE). A critical density model is suggested in which the melting volume is proportional to ionization period, if the period is above a critical value. The maximum melting radius depends on the time period of structural relaxation above the melting temperature, which increases with increasing initial substrate temperatures due to a lower heat dissipation rate. Furthermore, shock waves are observed to emit from CE core but the kinetic energy wave peak exists only in U sublattices. The absence of kinetic energy waves in O sublattices is explained by their relatively higher thermal vibration which cancels the work done from the compression waves. (C) 2015 Elsevier B.V. All rights reserved.

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