Shockwave Initiation and Detonation Physics

High explosives are metastable compounds. Violent reactions can be initiated by heat and/or impact. Shock initiation is concerned with studying the evolution of reaction in the explosive caused by a pressure pulse (shock wave) originating from either impact or an explosive source.

DE-9's studies in this field have resulted in collaborations with experimenters and theoretical and computational scientists from Los Alamos, Lawrence Livermore, and Sandia national labs, the Defense Department, and the United Kingdom's Atomic Weapons Establishment. The combined goal of the experimental and theoretical work is to produce better physics models of this aspect of high explosives' behavior for use in hydrocode computations. This is an important component of the science-based stockpile stewardship of nuclear weapons.

A current major effort involves studying the plastic-bonded explosive (PBX) 9502, a LANL-developed insensitive high explosive. The experiments are challenging because very high initial pressures—and thus very high projectile velocities—are required to initiate detonation. In addition, the large magnetic gauges combined with long run distances require that large explosive samples be used, which requires a large bore gun. These variables tax current gun technology and challenge the experimenters' creativity.

The overall configuration for our shock initiation experiments was developed at LANL in the 1980s. It shares gauging principles in common with those first used in the Soviet Union in the 1960s.