Mesoscale Probing of CRZ Structure in PBX: From Shock Ignition up to Detonation Failure

Paper reviews Portuguese contribution to the mesoscale study of PBX detonation which is being performed since 1996. We apply 96-channel optical analyzer for simultaneous measurements of light irradiation from detonation front (DF) surface and pressure field in chemical reaction zone (CRZ). This optical method, up to present, remains a unique diagnostic technique that offers the best compromise among high temporal and spatial resolution (600 ps and from 250 $\mu $m down to 50 $\mu $m respectively), large number of independent registration channels and design simplicity. This talk will address 3 major topics: dominant role of shear at shock initiation of PBX (results obtained in collaboration with NSWC-IH and LANL), origination of dissipative structures in CRZ of DW and related cellular structure of DF attended with ejecta (earlier recognized as DF ``roughness''), and relation between failure diameter and size of detonation cells.