摘要:

The existence of corpuscular radiation of high intensity in the vicinity of the earth was discovered by accident in the course of the first successful experiment of the United States IGY satellite program. The scientific equipment on our first satellite, 1958a—or, as it was popularly called, Explorer I—had been designed to measure the intensity of primary cosmic rays entering the upper layers of the earth's atmosphere. Although this equipment was capable of detecting and counting the number of ionizing events well in excess of any expected cosmic‐ray intensity, the telemetered recordings showed that the satellite was passing in and out of regions where the number of counts rose abruptly to a level where it saturated not only the counting circuits but even the Geiger‐Müller tube itself. Fortunately, by means of laboratory tests on similar instruments, it was possible to identify, at least approximately, the levels at which this saturation occurred and thereby to establish a lower limit for the magnitude of the radiation that was being enc

ISSN:0148-0227    

DOI:10.1029/JZ064i008p00865

年代:1959

数据来源: WILEY

摘要:

A geophysical experiment on global scale was conducted last fall. Three small A‐bombs were detonated beyond the atmosphere at a location in the south Atlantic. The purpose of the experiment was to study the trapping of the relativistic electrons (produced by the β‐decay fission fragments) in the geomagnetic field. The released electrons are trapped by this field oscillating along the magnetic lines between two mirror points. In addition to this motion the electrons drift eastward, creating a thin electron shell around the earth. The lifetime and location of the thus‐created global electron shell were measured by satellite‐ and rocket‐borne instruments. Auroral luminescence was observed at the conjugate points. The electron shell exhibited remarkable stability during its lifetime. No motion of the shell or change in its thickness was detected.This experiment was proposed by the writer a few weeks after the launching of the first Sputnik. After intensive investigations by several scientists it was decided by the end of April 1958 to go ahead with the experiment. All the necessary preparations were accomplished in the amazingly short time of 4 months.The usefulness of such electron shells for interpreting geophysical phenomena and possible future experiments are

ISSN:0148-0227    

DOI:10.1029/JZ064i008p00869

年代:1959

数据来源: WILEY

摘要:

Our four radiation detectors in satellite 1958ε (Explorer IV) easily and promptly observed the geomagnetically trapped electrons resulting from the three high‐altitude nuclear detonations Argus I, II, and III in August–September 1958. An account of over 160 satellite passes through the three Argus “shells” of artificially injected electrons is given herein, and a preliminary appraisal of the geophysical significance of these experiments is

ISSN:0148-0227    

DOI:10.1029/JZ064i008p00877

年代:1959

数据来源: WILEY

摘要:

Solid‐propellant rockets were sent to altitudes of 800 km from three stations in the eastern United States to observe electrons injected into the geomagnetic field from a small high‐altitude nuclear detonation. The electron flux was measured by an assembly of Geiger counters. Shortly after a nuclear detonation above the south Atlantic, a narrow region of high counting rate was observed. The geometry of the observations is related to the geomagnetic field. The region consisted of an intense band about 20 km wide (half‐width at half maximum counting rate) and less intense wings extending at least 700 km north and perhaps 700 km south of the band. Neither position nor width of the band changed during the observations, which consisted of periodic soundings until 100 hr after the nuclear detonation. The intensity of both the wings and the band decayed during the measurements as 1/t, which is consistent with the hypothesis that small‐angle scattering is the dominant loss mechanism. The angular distribution of the radiation was measured, and the electron flux was observed to be confined very nearly to a plane perpendicular to the field lines. Spectral measurements show far fewer electrons above 4 Mev than were expected from the fission beta spectrum. Betas trapped from the decay of neutrons emitted from large‐yield high‐altitude weapon tests in the Pacific were

ISSN:0148-0227    

DOI:10.1029/JZ064i008p00893

年代:1959

数据来源: WILEY

摘要:

A theoretical formulation has been made for the history of an artificial shell of geomagnetically trapped electrons resulting from low‐yielding nuclear detonations in the exosphere. The formulation assumes a source distribution and gives the spatial distribution of trapped electrons along the magnetic field lines, the drift rate around the world, and the configuration of the resulting shell. Interactions of the shell with the atmosphere lead to an electron density decaying inversely with time from injection for times longer than a characteristic lifetime that is a function of altitude and electron energy. The electron flux is found to be very nearly confined to a plane perpendicular to the field direction after several characteristic lifetimes. Scattering by geomagnetic fluctuations is probably not an important loss mechanism for the artificial shell, but it may be important for the hard component of the natural trapped belt. The effect of the geomagnetic anomaly over the south Atlantic has been described qualitatively. Jason rocket data and Explorer IV satellite data have been compared with the theoretical result

ISSN:0148-0227    

DOI:10.1029/JZ064i008p00909

年代:1959

数据来源: WILEY

摘要:

After each of the high‐altitude detonations in the Argus experiment, visual auroras were observed in the detonation area. After the third event an aurora was observed in the conjugate area. After the second and third events, signals attributed to hydromagnetic waves were detected in the conjugate region; these signals had a periodicity of about 1 cycle per second. The maximum change in the magnetic field was about 1 gamma. If propagated along the magnetic line of force the velocity was about 2000 km/sec. SporadicEwas observed after the third event in the conjugate area. Comparative records of the 5577 A and 3914 A lines were obtained in the detonation are

ISSN:0148-0227    

DOI:10.1029/JZ064i008p00923

年代:1959

数据来源: WILEY

摘要:

The radio effects of the Argus detonations were measured using (1) 30‐Mc radars designed to obtain echoes from the aurora or from the earth's surface mirrored in an enhanced ionospheric layer, (2) VLF receivers for monitoring distant transmitters or atmospheric noise sources in search of changes in signal strength, (3) riometers for recording cosmic noise absorption or VHF shot‐created noise at 30, 60, and 120 Mc.Results included (1) auroral echoes in the vicinity of the launch point after all three shots and near the conjugate points after the first and third shot, (2) sudden depressions of 6 to 12 db of the signal from England (19.6 kc) at Madrid and the Azores, (3) no ionospheric absorption at the conjugate locat

ISSN:0148-0227    

DOI:10.1029/JZ064i008p00933

年代:1959

数据来源: WILEY

摘要:

A preliminary outline of a new approach to the study of motions at meteor heights is given, the fundamental assumption being that these motions are perturbation velocities associated with propagating atmospheric waves. Several observed features of the largescale motions are thereby explained, and a basis is laid for the study of associated smaller‐scale “turbulent” motions. It is found that smaller‐scale motions having appreciable amplitude need not be anticipated a priori, contrary to an earlier conclusion derived from conventional turbulence

ISSN:0148-0227    

DOI:10.1029/JZ064i008p00939

年代:1959

数据来源: WILEY

摘要:

The search‐coil magnetometer carried on Pioneer I has yielded evidence of complex geomagnetic behavior at great distances from the earth. This paper is intended to report only some preliminary observations; in particular, what appears to be directional instability in the field. A comprehensive statistical analysis, to be reported later, is still in progres

ISSN:0148-0227    

DOI:10.1029/JZ064i008p00941

年代:1959

数据来源: WILEY

摘要:

Faraday fading of signals from an artificial satellite is analyzed in terms of the difference between the Doppler shifts of the ordinary and extraordinary components in the ionosphere. A procedure is outlined for determining the vertical distribution of electron density in the upper ionosphere. Explanations are given for the apparently excessive values of electron content yielded by measurements of Faraday fading and for the observation that the rate of Faraday fading is not exactly inversely proportional to the square of the wave frequency.

ISSN:0148-0227    

DOI:10.1029/JZ064i008p00945

年代:1959

数据来源: WILEY