B. D. Khristoforov

Craters of Large‐Scale Surface Explosions

Results of experimental studies of craters of chemical and nuclear surface explosions with commensurable heights of the center of mass and TNT equivalents on soils of different types are presented. Available databases were used, which are generally utilized for predicting ecological consequences of natural and man‐induced explosive catastrophes, development of new methods of monitoring and identification of phenomena under consideration, and their experimental and mathematical modeling.

Effect of Properties of the Source on the Action of Explosions in Air and Water

Results of an experimental study of parameters of the shock wave and explosion products in the near zone of explosions in air and water with a wide range of variation of explosion heat and charge density of high explosives are presented. It is shown that the influence of these characteristics on the action of explosions in the near zone can be characterized by one parameter: volume concentration of energy in the source. A change in this parameter involves a significant redistribution of energy between the explosion products and the shock wave, which can affect brisance and violate the energy similarity of explosions.

Action of the Coastal 1000‐Ton Surface Explosion on the Environment

Results of experimental investigations of the action of a coastal surface explosion of a 1000‐ton TNT charge on the environment are presented. Available databases were used, which are generally utilized for predicting ecological consequences of natural and man‐induced explosive catastrophes, development of new methods of monitoring and identification of phenomena under consideration, their experimental and mathematical modeling, and testing of the models being developed.

Parameters of radiative and gas-dynamic processes in air, near-ground, and ground explosions of charges with a mass up to 1000 tons

Results of measurements and processing of sizes, energy, and power of radiation of a cloud formed after an explosion of 50/50 TNT/RDX and TNT cast charges with masses ranging from 0.01 kg to 1000 tons on the ground surface and at different heights in air are presented; the measurements and data processing are performed within wide temporal (up to 10 s/kg1/3) and spectral (up to 28 µm) intervals. The results are compared with available published data. These explosives have the maximum radiative characteristics owing to the high content of carbon in explosion products. Under conditions of explosions in air, the measured emitted energy approaches 50% of the explosion energy. In the case of ground explosions, the radiation is anisotropic because of screening by ejected soil, and the ratio of energies emitted upward and along the ground surface can exceed the order of magnitude.

Analysis of Russian Hydroacoustic Data for CTBT Monitoring

Abstract — As part of a collaborative research program for the purpose of monitoring the Comprehensive Nuclear-Test-Ban Treaty (CTBT), we are in the process of examining and analyzing hydroacoustic data from underwater explosions conducted in the former Soviet Union. We are using these data as constraints on modeling the hydroacoustic source as a function of depth below the water surface. This is of interest to the CTBT because although even small explosions at depth generate signals easily observable at large distances, the hydroacoustic source amplitude decreases as the source approaches the surface. Consequently, explosions in the ocean will be more difficult to identify if they are on or near the ocean surface. We are particularly interested in records featuring various combinations of depths of explosion, and distances and depths of recording.¶Unique historical Russian data sets have now become available from test explosions of 100-kg TNT cast spherical charges in a shallow reservoir (87 m length, 25 m to 55 m width, and 3 m depth) with a low-velocity air-saturated layer of sand on the bottom. A number of tests were conducted with varying water level and charge depths. Pressure measurements were taken at varying depths and horizontal distances in the water. The available data include measurements of peak pressures from all explosions and digitized pressure-time histories from some of them. A reduction of peak pressure by about 60–70% is observed in these measurements for half-immersed charges as compared with deeper explosions. In addition, several peak-pressure measurements are also available from a 1957 underwater nuclear explosion (yield <10 kt and depth 30 m) in the Bay of Chernaya (Novaya Zemlya).¶The 100-kg TNT data were compared with model predictions. Shockwave modeling is based on spherical wave propagation and finite element calculations, constrained by empirical data from US underwater chemical and nuclear tests. Modeling was performed for digitized pressure-time histories from two fully-immersed explosions and one explosion of a half-immersed charge, as well as for the peak-pressure measurements from all explosions carried out in the reservoir with water level at its maximum (3 m). We found that the model predictions match the Russian data well.¶Peak-pressure measurements and pressure-time histories were simulated at 10 km distance from hypothetical 1-kt and 10-kt nuclear explosions conducted at various depths in the ocean. The ocean water was characterized by a realistic sound velocity profile featuring a velocity minimum at 700 m depth. Simulated measurements at that same depth predict at least a tenfold increase in peak pressures from explosions in the SOFAR channel as compared with very shallow explosions (e.g., ∼3 m depth).¶The observations and the modeling results were also compared with predictions calculated at the Lawrence Livermore National Laboratory using a different modeling approach. All results suggest that although the coupling is reduced for very shallow explosions, a shallow 1-kt explosion should be detectable by the IMS hydroacoustic network.

Investigation of the radiation characteristics of radiators based on combustion of aerosuspensions of aluminum powders

The results of measurements of radiation and gas-dynamic characteristics in combustion of an aluminum powder initiated by an electric explosion of a foil are given. Radiation energy in different spectral ranges is measured. The formation and movement of a cloud of combustion products is investigated. It is shown that effective sources of impulse radiation in the megajoule range can be developed on the basis of electric explosion in powders.