On Evidence of Substantial Atomization in Shallow Bubble Collapse Mechanism

We have recently fielded an experimental campaign to study the Shallow Bubble Collapse (SBC) mechanism on gas gun platforms.  The diagnostics included PDVs, Asay windows and foils, pyrometry and a new diagnostic for atomization measurement, Atomic Ejecta Source Optical Probe (AESOP). In both tin and cerium target materials, we have observed cooling thermal-radiance signatures that may suggest a significant amount of atomization, over 10%, in both materials.  AESOP sees quantifiable vapor at the leading edge of the ejecta field.  PDV records suggest that in some cases, enough vapor may have evolved in the cloud that the ejecta produced accelerate in vacuum. This talk will provide highlights from our diagnostic efforts in understanding the impact of atomization when the SBC mechanism is active.