BASIC THERMAL-RADIATION MEASUREMENTS

Basic thermal-radiation measurements, comprising total and broad-band spectral distribution of radiant energy, radiant energy function of field of view of the measuring instrument, and total radiant power versus time, are reported for the second thermal pulse of Shots 1, 2, 3, 5, 6, 9, and 10. All data were taken from ground stations at ranges as close as feasible to the detonations. The data are reported and analyzed to obtain the total thermal energy, the total thermal emission per unit of time, fireball sizes and geometries, and color and power temperatures, all as a function of time. New methods of analysis are used that show promise of correlating the thermal characteristics of the fireball with burst parameters. The new methods result in significantly higher thermal yields in all cases. Significant differences are shown in the thermal properties of tower and air bursts. The air bursts have higher thermal yields, higher peak temperatures, and different pulse shapes than tower bursts. The thermal properties of an air burst are shown to vary with altitude. The higher the altitude, the shorter the time scale, the larger the fireball, and the lower the total thermal energy. The peak temperature is little changed.