Electrical transients observed during underground nuclear explosions

Abstract

Electrical transients were recorded from eleven underground nuclear explosions at the Nevada Test Site and from one near Carlsbad, New Mexico. The electric field components are only a few microvolts per meter at distances less than 10 km from the shot point, and they generally decay approximately as the inverse cube of distance. Magnitudes are proportional to about the 0.4 power of yield. Two source mechanisms are considered: the formation of an elementary magnetic dipole by the conductive plasma expanding in the earth's magnetic field and the formation of an elementary electric dipole by radial asymmetry in the generation and absorption of • rays. The data accordingly were interpreted in terms of equivalent buried dipole sources.

Short‐time electrical effects during volcanic eruption: Experiments and field measurements

“…Thermohydraulic explosion represents the most violent phreatomagmatic activity, that is, the phreatomagmatic explosion [Zimanowski, 1998]. In the context of fragmentation of solid material [e.g., Petrenko and Gluschenkov, 1996;Yoshida et al, 1997Yoshida et al, , 1998], impact events [e.g., Crawford and Schultz, 1988; Adushkin and Soloviev, 2819 1996], and nuclear explosion [e.g., Zablocki, 1966], very high electric charges were detected on a short timescale, and in some cases a proportionality of signal strength and intensity of the respective process was reported. The potency of brittle-type fragmentation of molten volcanic rock to generate significant electrical signals on a short timescale in laboratory experiments was reported by Biittner et al [1997].…”

“…Experimental studies using very low viscosity ion and metal melts have shown that during explosive molten fuelcoolant interaction (thermohydraulic explosion) brittle fragmentation of the melt plays the key role for explosive surface enlargement and energy conversion [Zimanowski et al, 1997b; Bgttner and Zimanowski, 1998]. Thermohydraulic explosion represents the most violent phreatomagmatic activity, that is, the phreatomagmatic explosion [Zimanowski, 1998] 1996], and nuclear explosion [e.g., Zablocki, 1966], very high electric charges were detected on a short timescale, and in some cases a proportionality of signal strength and intensity of the respective process was reported. The potency of brittle-type fragmentation of molten volcanic rock to generate significant electrical signals on a short timescale in laboratory experiments was reported by Biittner et al [1997].…”

Field Measurement of the Electroseismic Response

“…The transients were so large in the vicinity of the shot chamber t.hat quantitative measurement of resistivity changes would have been extremely difficult. The potential, however, was interpreted by Zablocki (1966) and Rivers similar effects were not observed with the small chemical explosives also used in this study. In a different experiment,, an electrical signal generated (Martner and Sparks, 1959) at the instant a seismic wave intersected the base of the weathered layer was observed.…”

“…In large underground nuclear tests, lowfrequency electrical transients have been observed at the instant of detonation (Zablocki, 1966). The transients were so large in the vicinity of the shot chamber t.hat quantitative measurement of resistivity changes would have been extremely difficult.…”

The electromagnetic pulse from nuclear detonations

“…Thus it is natural to associate this signal component with the Compton electron model, as has been suggested by Bomke et al [1964]. Finally, Zablocki [1966] has reported measurements in the micropulsation to lower ELF range at a relatively short distance (15.7 km) from two low-altitude detonations of the 1958 Hardtack test series in Nevada. The polarization of the signals observed in these measurements implies a nearly vertical electric dipole source, as would be expected from the Compton electron model of signal generation as a result of the earth-atmosphere interface or of the atmospheric density gradient, rather than the magnetic dipole source that would result from the field displacement model.…”