摘要:

The existence of long‐term variations in cosmic‐ray intensity negatively correlated with sunspot activity, a discovery due to Forbush, has been explained by Davis in terms of a cavity in the galactic magnetic field centered about the sun. In the present paper, it is shown that a “diamagnetic” interplanetary region, rather than a “superconducting” one, can account for the cut‐off in the primary cosmic‐ray rigidity spectrum, as well as for the 11 year variations. The suggested diamagnetic region is an oblate spheroid in shape, with semiaxes of roughly 5×1015cm and 5×1014cm, and its effective permeability of 10−4implies a mean interplanetary field of about 10−9gauss. The 11‐year variations and the rigidity cut‐off are analyzed in detail o

ISSN:0148-0227    

DOI:10.1029/JZ063i001p00001

年代:1958

数据来源: WILEY

摘要:

Two Aerobee rockets were employed to eject relatively large amounts of sodium vapor into the earth's atmosphere. One of the flights occurred during evening twilight and sodium was placed in the sunlit atmosphere from 75 to 110 km. Sodium D‐line emission (λ 5890 A) was observed in the ejected trail above 90 km, and 5890 A is discussed in terms of resonance scattering of solar radiation. Below 90 km, D‐line radiation was not apparent, and the trail was white in appearance. This requires the formation of aerosols and indicates that sodium is unlikely to remain in the atomic state below 90 km.The second flight occurred at night. Strong D‐line emission and a persistent trail were observed at about 65 km, 100 km, and 140 km. This emission is discussed in terms of chemical processes which have been proposed to explain the sodium airglow. These processes cannot produce the observed brightness of the trail at the high altitudes. Excited atomic nitrogen (N2D) is proposed as a possible source of the energy. The observed presence of large amounts of energy stored in the earth's atmosphere above 100 km requires revision of some of the proposals regarding the sodium airglow and its

ISSN:0148-0227    

DOI:10.1029/JZ063i001p00019

年代:1958

数据来源: WILEY

摘要:

Ethylene gas was released from a rocket at 105 and 143 km in an attempt to detect atomic nitrogen in the upper atmosphere. The artificial chemi‐luminescence produced by the gas clouds was observed from the ground and recorded on Super‐Schmidt meteor cameras, using red‐sensitive and blue‐sensitive photographic plates. The color and intensity of each image can be related to the predominant chemical reaction producing the luminescence. The observations indicate that the lower cloud was caused by the reaction of ethylene and atomic nitrogen, and the upper cloud was caused by the reaction of ethylene with atomic

ISSN:0148-0227    

DOI:10.1029/JZ063i001p00031

年代:1958

数据来源: WILEY

摘要:

From a photometric study of the 5577 A airglow, made during 125 nights, extending over a two‐year period, from Sacramento Peak, New Mexico, the following conclusions can be drawn: (1) The regular features form a diurnal and seasonal repetitive pattern, for which the intensity during the equinoxes is brighter than during the solstices. A diurnal and seasonal variation in the direction and amplitude of the maximum intensity is observed. This suggests a model which supposes that an intensity pattern exists on the dark side of the earth. The diurnal variation at an observing station would be due to the earth's rotation and the seasonal variation due to the change in position of the ecliptic plane with respect to the observing station. (2) The two most important sporadic features observed were arc‐like structures, which appeared during six nights, and portions of auroral activity, observed during four nights. (3) From the 68 nights suitable for van Rhijn height determinations, a ratio ofI(75)/I(0) = 2.555, corresponding to a height of 85±68 km, was determined. (4) A triangulation attempt was made between Sacramento Peak and Capillo Peak, with a height between 80 and 100 km indic

ISSN:0148-0227    

DOI:10.1029/JZ063i001p00039

年代:1958

数据来源: WILEY

摘要:

Four rocket‐borne photometers measured nightglow emissions near λ 6300, λ 5893, λ 5577, and λ 5335. The emitting region of the oxygen green line, λ 5577, was entirely between 90 and 118 km, and had a very sharp lower boundary. The sodium D‐lines were encountered primarily between 85 and 110 km, with a maximum intensity at 93 km. The upper boundary of D‐line emission was not definite, due to tailing off of the distribution and low total intensity, but D‐line emission extending into the 130‐ to 150‐km region is indicated. The λ 6300 photometer showed two distinct features: an emitting region from 56 to 100 km, and a large signal still present at the peak of flight, 163 km. We attribute the 56‐ to 100‐km emission to the (9–3) Meinel OH band, and conclude that the region of oxygen red line emission must lie above 163 km. On the basis of relative band intensities for the Meinel OH bands and the dissimilarity of the signal‐νs‐altitude curves for the λ 5335 and λ 6300 photometers, we conclude that practically all atmospheric emission near λ 5335 is due to an atmospheric “continuum” and not due to OH band emission. This atmospheric “continuum” has a maximum intensity between 100 and 110 km, and is at least as bright as the stellar background.During descent of the rocket through theE‐region, the photometers recorded a bright glow in the rocket's wake. Energy for creating the glow had to come from atmospheric gases and not the rocket. Its

ISSN:0148-0227    

DOI:10.1029/JZ063i001p00051

年代:1958

数据来源: WILEY

摘要:

This paper reports an experimental study of the distribution of time intervals between bursts of 43.5‐Mc/s signals received over a 690‐km path from Stanford, California, to San Diego, California, with the object of determining whether or not the bursts occurred completely at random.The distribution of time intervals observed is consistent with the distribution expected if the bursts are produced by scattered radiation from the ionized trails of meteors which enter the upper atmosphere at random. The number of time intervals observed less than one second is appreciably less than the number calculated. This would be the case if some bursts were not observed when the interval between bursts is comparable to the duration of the bursts. The difference between observed and calculated values for large intervals for which the actual number of observations is small is not statistically significant. The observed number of triplets of equally spaced bursts substantially agrees with the number expected if the bursts occurred at random.The data used in this analysis were the intervals preceding 778 bursts observed during 0400–0600 hours on 3 August 1956 and those preceding 446 bursts observed during 0500–0700 hours on 6 Novemb

ISSN:0148-0227    

DOI:10.1029/JZ063i001p00067

年代:1958

数据来源: WILEY

摘要:

Study of world‐wide solar and geomagnetic data has shown a close association between flares with “major early bursts” at radio frequencies 200 Mc/s and sudden‐commencement geomagnetic storms. Intercomparison of Hα and radio‐frequency solar data for January 1949 to April 1956 has given positive evidence for such “major early bursts” with 115 of the approximately 3,000 flares observed during the 7–1/3 year interval. This type of radio‐frequency event is, therefore, relatively rare. Geomagnetic storms were reported by at least one observatory within less than five days after the occurrence of 92 per cent of the 115 flares with “major early bursts.” The average time interval between the flare and the start of the subsequent geomagnetic storm was slightly less than 2½ days. Average superposed values ofKpandApwere high on days 2, 3, and 4 after flares of importance 3 with “major early bursts,” but this was not the case after flares of importance 3 when emission at frequencies 200 Mc/s was not present or occurred only in the post maximum phase of the flare.The possibility of a “central meridian effect” has been investigated. The average, superposed values ofKpfor the disk passage of the 77 regions concerned is very similar to that “predicted” for disk passage of active regions with storm‐producing flares in random positions, and with double frequency and/or effectiveness for the five days nearest central meridian passage. The latter assumptions are in accordance with observations.The geomagnetic effectiveness of each of the 115 flares with “major early bursts” was re‐evaluated on the basis of all available world‐wide solar data. Sixty‐eight of the 115 flares were considered to be the most probable single solar cause of 68 geomagnetic storms. Study of these 68 cases of well‐associated flares and geomagnetic storms indicated that storm‐producing flares occurred at all meridian distances and in all importance categories. However, centrality of position and high flare importance favored greater severity in the subsequent storm. Again, the average time int

ISSN:0148-0227    

DOI:10.1029/JZ063i001p00077

年代:1958

数据来源: WILEY

摘要:

Booker [see 1 of “References” at end of paper] and Booker and Cohen [2]have given reasons for thinking that application of fluid mechanics to meteoric phenomena leads to results in discord with previous thought. This has led to a discussion [3] that is continued in this paper. An underlying feature of the discussion is a phenomenon that may be described as the rough trail paradox. This arises from the fact that the turbulence velocity of the large eddies is about ten times greater than the turbulence velocity of the small eddies. For a trail that has been rendered rough by the small eddies, let us examine the echoes from two points, separated by a distance of the order of the large eddy size. Due to the motion of the large eddies, interference between these two points is taking place at a rate ten times faster than the rate at which the phase of the echo from either point is taking up random values due to the motion of the small eddies. The upshot is that, as already mentioned by Booker [1], the most obvious features of the fading of long‐duration meteor echoes are controlled by the motion of the large eddies even when the mechanism of return is backscattering associated with the small eddies. Failure to appreciate this point seems to have led Manning and Eshleman [3] to claim as an antithesis to the Kolmogoroff‐Heisenberg theory of turbulence results that, in fact, are consistent

ISSN:0148-0227    

DOI:10.1029/JZ063i001p00097

年代:1958

数据来源: WILEY

摘要:

Examination is made of the residual intensity of energy received between the atmospherics at a frequency of 520 kc. The nature of the junction between the earth's and the sun's atmosphere, and the manner in which an electromagnetic wave travels through an overdense ionosphere are briefly described. The way in which an ionospheric shutter opens and closes is explained, plus examples shown and reduced. A celestial component is found at declination −6°, which has a maximum at 2200 hours right ascension and a minimum at 0700 hours. The maximum intensity is 4×10−20jansky per steradian. Unexpected variations at night may be due to auroral particles of low energy. Manifestations of strong precipitation static and local atmospherics are described. A few observations were made at 1

ISSN:0148-0227    

DOI:10.1029/JZ063i001p00109

年代:1958

数据来源: WILEY

摘要:

The wave‐guide mode theory of VLF propagation for a sharply‐bounded homogeneous ionosphere is refined to include stratification at the lower edge of the ionosphere. The numerical results for a two‐layer model are discussed in detail. By choosing the upper medium to have a conductivity with a factor of 10 greater than the lower medium, the attenuationvsfrequency characteristic of the model is consistent with experimental data from 1.0 to 20 kc. The effect of the finite thickness of theElayer, important for frequencies less than 1.0 kc, is treated by an ionospheric model which has a sharp lower edge and an exponential taper to zero at greater he

ISSN:0148-0227    

DOI:10.1029/JZ063i001p00125

年代:1958

数据来源: WILEY