High-altitude Explosion Research Articles

Activities Of The Yakutsk Geophysical Observatory (Cosmic Ray Laboratory) In 1928–1962

The relevance of the research topic is related to the generalization of the Soviet experience in formation and development of cosmophysical research in Yakutia over several decades, from the activities of weather stations to the creation of the Institute of Cosmophysical Research and Aeronomy of the Yakutsk Branch of the USSR Academy of Sciences. The formation of the network of 23 stationary meteorological and upper-air stations and the Geophysical Observatory is disclosed. The first stage of the activity of these institutions was identified as of high practical importance in the development of aviation, gold mining industry on Aldan and Amur-Yakutsk highway construction.The second stage was characteristic by innovative developments of Yakut scientists as semiconductor devices for artificial Earth satellites, cameras for shooting auroras, and an ionization camera for continuous registration of cosmic rays, that received worldwide recognition. Study of radiation situation in near-Earth space during solar flares and high-altitude thermonuclear explosions testified, that Yakutia contributed to increasing of the country's defense capability. Particular attention is paid to the activities of the station on Bolshoy Lyakhovsky Island of the Novosibirsk Islands, which served Arctic aviation flights and coastal navigation along the Northern Sea Route.

Research on Endpoint Detection Algorithm in High Altitude Explosion Point Location Technology

Aiming at the problem of inadequate positioning accuracy of sound endpoints by the dual-element single-threshold endpoint detection algorithm and the single-element dual-threshold endpoint detection algorithm in the process of locating the sound source of weather modification bombs at high altitudes during artificial weather modification, a multi-element dual threshold endpoint detection algorithm. First, according to the characteristics of high-altitude explosion of weather modification bombs and ground reception, the sound signal is filtered and denoised, divided into frames, and windowed. Then, the time-domain feature short-term energy, short-term zero-crossing rate and frequency domain feature short-term information entropy of each frame of the sound signal are calculated, and double thresholds are set for detection. In this way, the start and end points of the explosion sound in the collected sound signal are found, and the data is imported into the positioning algorithm for processing, and then the explosion point of the weather modification bombs in the high air is located. The test results show that the method can accurately distinguish the end point of effective explosion sound, and has practical application value for the location of the sound source of the high-altitude explosion point of the weather modification bombs.

On the Effect of Weak Attenuation of Acoustic Waves from High-Altitude Explosions

The article analyzes difficult to explain experimental data on acoustic signals recorded from explosions and injections of matter at heights of 120–150 km. It is noted that a significant part of the acoustic energy of high-altitude explosions reaches the Earth’s surface without significant absorption. Based on an analysis of a nonlocal three-flux gas-dynamic model, transformation of a strong blast wave in air into a continuous disturbance, a hypothesis is proffered about the sequential decay of a wave from a high-altitude explosion into wave packets (wave trains). A significant fraction of the blast energy should be transferred by such wave packets during their motion from top to bottom throughout the atmosphere, which should be virtually “transparent” to such acoustic disturbances.

Determination of the height of the “meteoric explosion”

When cosmic bodies of asteroidal and cometary origin, with a size from 20 to approximately 100 m, enter dense atmospheric layers, they are destroyed with a large probability under the action of aerodynamic forces and decelerated with the transfer of their energy to the air at heights from 20–30 to several kilometers. The forming shock wave reaches the Earth’s surface and can cause considerable damage at great distances from the entry path similar to the action of a high-altitude explosion. We have performed a numerical simulation of the disruption (with allowance for evaporation of fragments) and deceleration of meteoroids having the aforesaid dimensions and entering the Earth’s atmosphere at different angles and determined the height of the equivalent explosion point generating the same shock wave as the fall of a cosmic body with the given parameters. It turns out that this height does not depend on the velocity of the body and is approximately equal to the height at which this velocity is reduced by half. The obtained results were successfully approximated by a simple analytical formula allowing one to easily determine the height of an equivalent explosion depending on the dimensions of the body, its density, and angle of entry into the atmosphere. A comparison of the obtained results with well-known approximate analytical (pancake) models is presented and an application of the obtained formula to specific events, in particular, to the fall of the Chelyabinsk meteorite on February 15, 2013, and Tunguska event of 1908, is discussed.

Numerical simulation of the ionization effects of low-and high-altitude nuclear explosions

Low-altitude and high-altitude nuclear explosions are sources of intensive additional ionization in ionosphere. In this paper, in terms of the ionization equilibrium equation system and the equation of energy deposition of radiation in atmosphere, and considering the influence of atmosphere, the temporal and spacial distribution of ionization effects caused by atmospheric nuclear detonation are investigated. The calculated results show that the maximum of additional free electron density produced by low-altitude nuclear explosion is greater than that by the high-altitude nuclear burst. As to the influence of instant nuclear radiation, there is obvious difference between the low-altitude and the high-altitude explosions. The influence range and the continuance time caused by delayed nuclear radiation is less for the low-altitude nuclear detonation than that for the high-altitude one.

High-altitude explosions and their magnetohydrodynamic description

The paper provide, approaches for formulating general ideas of a gas dynamic stage for an explosion in the upper atmosphere in which the geomagnetic field is of importance. Various versions concerned with magnetic pressure influence, particle collisions, and the latitudinal atmosphere nonuniformity are discussed. The following magnetogasdynamic models are constructed: 1) a quasitwo-dimensional model which treats the spherically symmetric flows with the magnetic force averaged over angles, 2) a two-dimensional model, and 3) a three-dimensional model. The latter model is applied to a general case of an arbitrary directed magnetic field. The computational results obtained for particular flows according to the magnetohydrodynamic (MHD) models are given. In the next paper we substantiate the MHD-theory application even for very rarefied magnetified plasma

Orbital barium CRRES injection — Effective source of ionospheric wavelike disturbances

Spectral analysis of artificial wavelike disturbances (WD) in ionospheric parameters is presented. The sources of WD are barium clouds injections in CRRES perigee experiments. Plasma concentration pulsations are found in the ionospheric F2 layer maximum over Havana (Cuba) at distances 1500–2500 km from the barium injection. It was found that for the spectral component with 10 min period, the delay (relative to injection moment) corresponded to WD propagation velocity in 323–390 m/s band and depended on the specific injection conditions. It was shown that in every experiment the WD effective propagation velocity in the terminator region correlated with the sunlit part of the trajectory from the injection point to Havana. When comparing this WD type with WD's of other origins (from earthquakes, high-altitude explosions and solar terminator), it was shown that purposeful injection in the ionosphere of even a small barium quantity with orbital velocity in terminator region might be the effective means for generation or amplification of natural WD.

Comparison of the low-altitude inner-zone 55-Mev trapped proton fluxes measured in 1965 and 1961-1962

55-Mev trapped proton flux data obtained from nuclear photographic emulsions exposed in Air Force satellites in the 200–400-km altitude interval during 1965 are compared to data previously reported. No significant decay is detected since mid-1963, and in fact a slight increase is observed. During this period a decay of a factor of almost 2 is expected following the redistribution observed in July 1962 due to the high-altitude Starfish explosion. The 1965 absolute flux levels are found to be in reasonable agreement with those predicted by Blanchard and Hess on the basis of solar cycle atmospheric density variations and neutron albedo injection. The relative increase observed depends more on solar cycle atmospheric density changes than on the source mechanism as long as the source strength is of the magnitude used by Blanchard and Hess and reasonably constant.

The effects of the high-altitude thermonuclear explosion 9 July 1962 as recorded on “Cosmos-5”

The effects of the high-altitude thermonuclear explosion 9 July 1962 as recorded on “Cosmos-5”

Techniques for detection of high-altitude nuclear explosions

The Central Radio Propagation Laboratory (CRPL) is conducting a study for the Advanced Research Projects Agency (ARPA), Project VELA, of ground-based techniques for detecting geophysical effects produced by nuclear explosions at altitudes above about 20 km and in space. This activity has been designated HANDS, an abbreviation for High-Altitude Nuclear Detection Studies. A substantial amount of experimental data exists on effects produced by high-altitude explosions and theoretical predictions have been made of effects expected from explosions in space. The ability to record and identify these signatures is limited by a lack of knowledge of natural variations, especially those having fractional-second onset times. The objective of the HANDS is to develop methods for detecting nuclear explosion effects in the natural background. The experimental facility for collecting and processing background data from a collection of colocated geophysical sensors is described.

Detection of high-altitude explosions by observation of air fluorescence

X-rays radiated from a nuclear explosion in space excite fluorescence of air molecules in the upper atmosphere. The fluorescence has a characteristic space-time signature which can be recognized from the ground even against a bright daylight sky. The criteria determining detectability and range are discussed, along with a number of practical systems of detection. False alarms, caused mainly by lightning flashes, can cause excessive triggering of single-station detectors unless discrimination techniques are employed. They also compel reliance on a net of stations for reliable recognition of true, nuclear explosion induced fluorescence.

Precipitation of energetic electrons into the atmosphere

Measurements were made of electron fluxes and spectrums above 900 kev at altitudes between 200 and 700 km in early September and October 1962 aboard two near-polar Air Force satellites. The particle fluxes were observed with shielded solid-state detectors having a 2π solid angle. The results show that electrons are lost from the radiation belts into the atmosphere along narrow ranges of L near L = 1.2 and L = 2 as well as in the L = 3 to 8 region. The L = 2 and L = 3 to 8 fluxes and spectrums exhibit temporal variations. A typical precipitating flux at B = 0.35 gauss, L = 2.0, is 103/cm2 sec with E > 0.9 Mev. A typical integral energy spectrum for L = 2, B = 0.35 gauss, is E−3 between 0.9 and 1.7 Mev. Comparison of results with pre-Starfish measurements indicates that the fluxes of electrons observed near L = 1.2 and L = 2 are not connected with the high-altitude explosion of July 9, 1962.

Preliminary analysis of the fluxes and spectrums of trapped particles after the nuclear test of July 9, 1962

Particle detectors have been flown on a low-altitude, polar satellite to measure the fluxes and energy spectrums of protons and electrons. In the region of the South Atlantic magnetic anomaly, electrons were observed with a fission-like spectrum above 2 Mev. Comparison on B, L plots of the electron fluxes with those obtained one week after the explosion indicates that the electron lifetime is ≳20 days. The lifetime and the observed deficiency of fission electrons below 2 Mev are consistent with the loss mechanism of atmospheric interaction. Near L = 4.5 and B = 0.4 gauss, only natural electrons were observed. The proton flux and spectral measurements yield no evidence that protons were either injected into or removed from the radiation belt by the high-altitude explosion.

Effect of the Johnston Island high-altitude nuclear explosion on the ionization density in the topside ionosphere

We report here the first direct measurements of the effect of high-altitude nuclear explosions on ionization density above the F2 layer. The Birmingham RF electron density probe carried in satellite Ariel (perigee 400 km, apogee 1200 km, inclination 54°, period 101.4 minutes) has monitored the ambient electron density along the satellite orbit from the date of launch on April 27, 1962 [Sayers et al., 1962]. After the high-altitude explosion near Johnston Island (latitude 16°N, longitude 169°W) at 0900 UT on July 9, 1962, abnormally high electron densities were recorded for a few minutes on each of five successive satellite orbits. The times and places at which these high densities were observed are listed in Table 1, together with values of ‘enhanced’ and ‘normal’ electron densities, the latter estimated from similar orbits on the day before the explosion. The explosion occurred on the nighttime side of the earth, and the ‘enhanced’ electron densities recorded by the satellite are similar to normal daytime densities at the same places. The location of the enhanced ionization along the satellite orbit in terms of latitude and longitude is shown in Figure 1, in which Johnston Island, its conjugate point, and the magnetic equator are also indicated.

Observations of earth-potential gradients at the time of a high-altitude thermonuclear explosion

Observations of earth-potential gradients at the time of a high-altitude thermonuclear explosion

Variations in the total electron content of the ionosphere after the high-altitude nuclear explosion

Abstract From measurements of the amplitude of the 54 Mc/s signals from the satellite Transit 4A, the total electron content of the ionosphere up to a height of 920 km is calculated. Thirty-five minutes after the high-altitude explosion the electron content over Auckland was twice the normal value of 4·2 × 1016 electrons per m2. South of Auckland, over Nelson, the electron content increased to about three times the normal value. The Faraday fading of the signals almost completely disappeared north of Auckland, and this effect cannot be explained by normal ionospheric absorption of the extraordinary component.

A possible hydromagnetic duct in relation to high-altitude explosions

It is shown that at a height of 400 km in the atmosphere there may exist a hydromagnetic duct permitting propagation of effects for Johnston Island to New Zealand in the observed time of 40 sec. (auth)

Lower ionospheric effects near the conjugate point of the 9 July 1962 high-altitude explosion

Abstract For a period of 60 seconds after the explosion above Johnston Island, absorption of 42 Mc/s radio waves occurred in the conjugate area. The observations can be explained on the basis of ionisation by decay electrons from neutrons emitted from the explosion material. An electron concentration of not less than 4 × 104 per cm3 during the first few seconds after detonation occurred at about 70 km altitude in the conjugate area.

New Zealand Observations of the High-Altitude Explosion of July 9 at Johnston Island

The principal observations in New Zealand of geomagnetic and atmospheric effects of the explosion of July 9 over Johnston Island are summarized. Outstanding features of the explosion were the intensity of the effects, which caused off-scale readings on many instruments, and evidence for the precipitation of particles over an area extending about 25 deg farther south than the magnetic conjugate point. (L.T.W.)

Infrared radiation from the atmosphere resulting from high altitude explosion X-rays

This paper presents calculations of the infrared radiation resulting from the upper atmosphere being excited by a very high altitude nuclear explosion. The mechanism considered is that of X-ray absorption to form a layer of hot air leading to the formation of NO molecules and the subsequent radiation at the fundamental at 5·4 microns and the first overtone at 2·7 μ.