Validation of source region energy partition calculations with small-scale explosive experiments

Abstract

The decrease in signal energy as the location of a nuclear explosion varies from deep in the ocean to above the ocean surface is a concern for the planned ocean monitoring component of the Comprehensive Test Ban Treaty. Small-scale experiments were designed to validate predictions of energy coupling by nuclear explosions in the ‘‘source region,’’ the origin of the signals that propagate in the deep underwater sound (SOFAR) channel. The experiments were performed in a biologically dead lake at a scale length of 1/50 (1/125 000 in explosive energy) relative to one kiloton using 6.82-kg charges of Pentolite 50/50. The acoustic energy coupled into the water was monitored at a 60-m range by a hydrophone string with eight piezoelectric sensors spaced from near-surface to a 30-m depth. Useful data were obtained at five burst locations: 5, 2, 0, −2, and −15 m. Results from the experiments and new calculations support the predicted energy partitioning for above-surface explosions with model and experiment peak pressures agreeing within a factor of two over three orders of magnitude variation. [Work performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under Contract W-7405-ENG-48.]