摘要:

Two increases of about 100 per cent in the cosmic‐ray nucleonic intensity were recorded at Mount Washington and Durham, New Hampshire, on November 12 and 15 following large solar flares. A third small increase was observed on November 20. The two large increases exhibited different features, and these differences are discussed in relation to solar phenomena. From a study of the world‐wide nucleonic intensity data it is found that: (1) the rigidity spectrum can be expressed asKP−n, withn= 6 for both flares; (2) for the increase on November 12, there is particle dispersion, and an approximate evaluation of the diffusion has been made; (3) the classical impact‐zone theory does not apply for these flares, evidence being presented for the existence of magnetic fields and some scattering effects between the earth and

ISSN:0148-0227    

DOI:10.1029/JZ066i010p03083

年代:1961

数据来源: WILEY

摘要:

Balloon measurements, obtained over Fort Churchill, Canada, of solar cosmic ray intensity during July 1959 are reported. The intensities observed on July 11, 12, and 18 were many times as great as those observed simultaneously at Minneapolis. In particular, the excess Geiger counter rate at Fort Churchill was 100±25 times as great as the corresponding rate observed at Minneapolis during a small influx of radiation which occurred at 0730 UT on July 11 (before the magnetic storm that began at 1620 UT July 11). Measurements of the dependence of excess rate on atmospheric depth indicate that the energy spectrum of the solar cosmic rays did not change significantly over a period of 10 days

ISSN:0148-0227    

DOI:10.1029/JZ066i010p03095

年代:1961

数据来源: WILEY

摘要:

Measurements of the elevation angle of signals received from a satellite below the peak of theFlayer enable the electron density at the height of the satellite to be calculated directly with an accuracy of a few per cent. The variation of the electron density with height can then be determined up to the peak of theFlayer. Full allowance is made for the effects of refraction and of curvature of the earth. The results are largely independent of the presence of small irregularities in the ionosphere or of large‐scale horizontal gradient

ISSN:0148-0227    

DOI:10.1029/JZ066i010p03103

年代:1961

数据来源: WILEY

摘要:

Several investigators have interpreted experimental data as evidence that the passage of artificial earth satellites creates large‐scale disturbances in the ionosphere. In an effort to confirm this hypothesis, a search for such effects in the immediate vicinity of Sputnik III and Echo I has been conducted with the aid of an HF radar having a comparatively broad beamwidth, both in azimuth and in elevation. Possible satellite‐associated disturbances were sought both as direct reflections from the vicinity of the vehicle and as perturbations within theFlayer sufficient to alter the structure and appearance of ground backscatter mirrored by that layer. In an appreciable fraction of the 139 observations made, the equipment would have registered either type of disturbance, owing to direct illumination of the passing satellite by high‐angle radiation from the transmitter, and illumination of the distant ground by lower‐angle energy reflected down from the ionosophere beneath the satellite's track. In all this work, the fundamental assumption was made that, if an effect were produced, it would be closely associated with the satellite passage in time, and it would also occur comparatively close to the satellite's track in space. No observed returns could be attributed to direct reflection. Many layer anomalies were found to occur at locations below orbiting vehicles, at times close to the time of vehicle passage. Subsequent study of these anomalies, and comparison with statistical and other characteristics of natural changes, did not provide any basis for believing any of the anomalies to be satellite‐caused. It was concluded that all phenomena detected were of natur

ISSN:0148-0227    

DOI:10.1029/JZ066i010p03109

年代:1961

数据来源: WILEY

摘要:

An approximate analysis is carried out for mode propagation in the earth‐ionosphere waveguide with the height of the boundary varying with distance. Particular attention is paid to the phase anomaly produced by a localized depression of ionosphere heigh

ISSN:0148-0227    

DOI:10.1029/JZ066i010p03119

年代:1961

数据来源: WILEY

摘要:

On ionograms obtained near the magnetic equator the rectangular configuration called ‘equatorial spreadF’ arises from scattering in the vertical plane (passing through the ionosonde) normal to thin, magnetic field‐aligned irregularities located at or beneath the base of theFlayer [Cohen and Bowles, 1961]. It is shown in the present paper that some strikingly different spread‐Fconfigurations on equatorial ionograms are due to irregularities of the same kind, but embedded in theFlayer. Since these other configurations result from similar irregularities, the category of ‘equatorial spreadF’ is generalized to include them. An ‘ionogram’ corresponding to scattering from an individual ‘equatorial spreadF’ irregularity can be calculated. A composite ionogram resulting from a number of such scatterers can then be synthesized by superposition. By appropriate distributions of scattering centers in the east‐west plane, many features of the ‘equatorial spread‐F’ configurations observed on Huancayo ionograms can be simulated. This process of ionogram synthesis constitutes a new technique for the determination of (1) the height of patches of small‐scale irregularities in theFregion; (2) the horizontal distance of the patches from the ionosonde in the vertical east‐west plane; (3) the thickness of the patches; (4) their‐east‐west extent; and (5) the east‐west component of their drift velocity. The patches are measured to have an east‐west extent of up to 300 km and a thickness between 10 and 50 km. Their drift velocity is eastward, gradually decreasing from 200 to 100

ISSN:0148-0227    

DOI:10.1029/JZ066i010p03125

年代:1961

数据来源: WILEY

摘要:

A waveguide model is presented for propagation of radio waves along elongated irregularities aligned parallel to the earth's magnetic field in the equatorial ionosphere. This theory is applied to analyze the frequency spread ionograms often observed during the equatorial night, particular attention being devoted to the detailed striations of the spread; similar spread‐Fstriations on arctic ionograms are explained by a corresponding waveguide theory. The waveguide theory is consistent with direction‐finding evidence that the category of spreadFconsidered in this paper is caused by back‐scatter in the north‐south plane from irregularities thatdo notsupport north‐south forward scatter at 50 Mc/s. These echoes are in contrast to those arriving in the eastwest plane from the ‘equatorial spreadF‘ irregularities considered elsewhere, whichdosupport north‐south forward scatter at 50 Mc/s. This paper is concerned with propagation in an irregular ionosphere, but not with the formation of the

ISSN:0148-0227    

DOI:10.1029/JZ066i010p03141

年代:1961

数据来源: WILEY

摘要:

The forces acting upon an electron in an ionized gas are investigated to determine the index of refraction of the medium. The result previously established by Darwin that the force due to the polarization field in an ionized gas of low concentration is canceled by the effect of collisions between ions and electrons is re‐established in a simple manner that clearly displays the physical basis for the effect. Because of this cancellation the Sellmeyer formula,n2‐1=‐Ne2/∈0mω2determines the relation between the electron number density,N, and the index of refraction,n, in the ionosphere when collisions are neglected. It is shown that this result is independent of the effects of free‐electron orbits which penetrate the orbits of bound electrons and of the effect of asymmetric charge distributions in the ions. The breakdown of the theory at high frequencies is

ISSN:0148-0227    

DOI:10.1029/JZ066i010p03157

年代:1961

数据来源: WILEY

摘要:

Analysis of radio noise records from Kekaha, Hawaii, and Ohira, Japan, during 75 solar flares occurring during August, September, and October 1958 reveals a positive relationship between short‐time noise power decreases and solar flares. The most significant noise fadeouts associated with flare eruptions occurred with the sun over one of the major noise centers contributing to the noise level at the measuring station. Maximum noise decrease of 18 db was observed on 5.0 Mc/s at Kekaha when the sun was over the East Indies noise center, just after sunset at the receive

ISSN:0148-0227    

DOI:10.1029/JZ066i010p03163

年代:1961

数据来源: WILEY

摘要:

The Tiros meteorological satellite contains detectors, storage, and telemetry for the measurement of infrared and reflected solar radiation from the earth and its atmosphere. Two separate detector designs are employed: a medium‐resolution scanning radiometer and a low‐resolution nonscanning radiometer. The spin of the satellite provides the scan line of the medium‐resolution radiometer, which is then advanced by the orbital motion of the satellite. Five channels using bolometer detectors and filters to limit the spectral response from 6 to 6.5 microns, 8 to 12 microns, 0.25 to 6 microns, 8 to 30 microns, and 0.55 to 0.75 micron are mounted in a single housing with choppers and pre‐amplifers. The spatial resolution is about 40 miles square when viewing the earth directly beneath the satellite. The parameters studied by these spectral regions are, in the same order: radiation emerging in the water vapor absorption band, day and night time cloud cover, albedo, thermal radiation, and visual maps for comparison with television pictures from the vidicon cameras also carried in the satellite. The low‐resolution nonscanning radiometer, utilizing a simple unchopped design, measures the blackbody temperature and the albedo of the earth. The field of view of the detector when viewing the earth directly beneath the satellite is a circle of 450‐mile diameter and covers part of the area of each picture frame of the wide‐field television camera. The detector consists of two thermistors, each mounted in the apex of a reflective Mylar cone which provides optical gain. One thermistor, coated black, responds to both reflected solar radiation and the thermal radiation from the earth; the second reflects solar radiation and responds only to the thermal radiation. The design, calibration, performance, and data reduction of both systems

ISSN:0148-0227    

DOI:10.1029/JZ066i010p03169

年代:1961

数据来源: WILEY