摘要:

The ionospheric electron density profiles recently measured by multiple frequency radio absorption technique are compared with those profiles deduced from particle measurements at balloon altitudes. The electron densities predicted on the basis of the ionospheric parameters and exponential rigidity spectrums of Freier and Webber agree well with the measured profiles. The use of Kane's revised values for the collision frequency along with the predicted electron densities give absorptions somewhat smaller than measured values for some solar events. The contribution of solar α particles to the electron densities should be included to resolve the discrepancy

ISSN:0148-0227    

DOI:10.1029/JZ068i023p06223

年代:1963

数据来源: WILEY

摘要:

The phase stability of one‐hop whistler mode signals on 18.6 kc/s from the VLF transmitter NPG near Seattle, Washington, has been observed in New Zealand. These signals are characterized by a change in frequency, presumably introduced by variations in the phase path length. The observations indicate that the phase path length can alter at a rate of about 1 km/sec, and total phase path changes of the order of 200 km can occur in a period of 3 min. Possible methods of determining where and how the phase variations occur are suggeste

ISSN:0148-0227    

DOI:10.1029/JZ068i023p06229

年代:1963

数据来源: WILEY

摘要:

The west‐to‐east nighttime reversal in longitudinal auroral motions is observed at Byrd, Antarctica, as at other auroral zone stations. Because of the high geographic latitude of the station, it is possible to see the aurora throughout the day, and a second reversal in longitudinal motion is observed. This reversal, from eastward to westward motion, tends to occur approximately 10 hours later than the nighttime reversal. The morphology of the ‘day‐time’ aurora is described here; it differs in several ways from that of the aurora commonly observed in the hours near local midnight at this and other auroral zone

ISSN:0148-0227    

DOI:10.1029/JZ068i023p06237

年代:1963

数据来源: WILEY

摘要:

The dependence of the amplitude of radio interferometer fringes on the statistical properties of an ambient diffraction field is discussed. Using a multiple‐spacing phase‐switched radio interferometer fringes on the statistical properties of an ambient diffraction field is discussed. Using a multiple‐spacing phase‐switched radio interferometer it is possible to deduce the sum of the mean square amplitude and phase fluctuation indices, and also the scale sizeLof the diffraction pattern. Using a multiple‐spacing phase‐swept radio interferometer, we can deduce values of the mean square amplitude fluctuation indexand the scale sizeL. Simultaneous measurement on both types of equipment provides an estimate of the mean square phase fluctuationwhich gives a measure of the importance of multiple scattering in the diffraction process. The radio source in Cassiopeia has been observed at low elevation angles by a phase‐swept interferometer at a frequency of 53 Mc/s (looking north from Ithaca, New York). Experimental results obtained during the time of a radio star fadeout indicate values ofbetween 0.37 and 0.57 and scale sizes of the order

ISSN:0148-0227    

DOI:10.1029/JZ068i023p06243

年代:1963

数据来源: WILEY

摘要:

The theory of radar reflections from a rough planetary surface is examined for the case of deep modulation where the surface correlation function consists of two components having greatly different structure sizes. It is found that a modified superposition principle holds for the angular power spectrum and that the individual components may be detectable by high‐resolution pulse techniques. Recent lunar experiments by Mehuron are found to show the existence of two such components. The theory also leads to the conclusion that the angular power spectrum of the echoes cannot be computed from the results of CW measurements for the type of surface considere

ISSN:0148-0227    

DOI:10.1029/JZ068i023p06251

年代:1963

数据来源: WILEY

摘要:

Under the influence of the sun and the moon a highly eccentric orbit of a satellite can become a nearly circular one or a nearly circular orbit might become eccentric. In light of this I suggest a combination of the Gibbsian rotation vector and the Hamiltonian vector as a nonsingular set of elements to be used for all eccentricities and all inclinations. The method of Halphen is suggested for the computation of secular effects, and the method of Liouville for the computation of the near resonance effects caused by the commensurability of mean motions of the disturbed and the disturbing body. The combination of these two methods can give information about the general behavior of the orbit of a minor planet over an interval of some thousands of years, and of an artificial satellite moving in cislunar space over an interval of a number of years.

ISSN:0148-0227    

DOI:10.1029/JZ068i023p06255

年代:1963

数据来源: WILEY

摘要:

Electron‐sensitive photographic emulsions were placed at points where lightning strokes occurred to a 300‐m tower. No tracks of high‐energy electrons, which might have been associated with lightning, were observed. A search for radioactivity also showed no effects of ligh

ISSN:0148-0227    

DOI:10.1029/JZ068i023p06261

年代:1963

数据来源: WILEY

摘要:

Data for altitudes up to 60 km over Fort Greely, Alaska, are analyzed and presented as a description of the atmospheric acoustic structure for subpolar northern hemisphere latitudes. Mean‐component sonic profiles are constructed and discussed. Results show that detailed regional and seasonal acoustic profiles can be established with data now available; however, a more inclusive and comprehensive treatment of atmospheric acoustic data is desirable. One such study that is currently being made at White Sands Missile Range is describe

ISSN:0148-0227    

DOI:10.1029/JZ068i023p06267

年代:1963

数据来源: WILEY

摘要:

The ratios of the internal to external source terms of the earth's surface potential for certain geomagnetic fluctuations are indicative of the electrical conductivity of the earth's interior. A nonlinear first‐order differential equation is derived for these ratios as functions of depth and conductivity in a spherically symmetric earth. This equation may be solved numerically to match an observable surface ratio with a conductivity‐depth profile, or it may be solved analytically for a few of the infinite number of possible profiles. This approach provides a good qualitative insight into the problem of geomagnetic induction in a concentrically stratified ea

ISSN:0148-0227    

DOI:10.1029/JZ068i023p06273

年代:1963

数据来源: WILEY

摘要:

Most attempts to use the worldwide magnetic fluctuations to study the earth's conductivity structure have been concentrated on the 24‐hour variations and the magnetic storm transients. Some of these results have been inconsistent, possibly because of the ocean effect and the complex mode structure of the variations. Longer‐period fluctuations, considered to be due to modulations of the storms, are less subject to these difficulties. Spectral analyses of magnetic station data have been made in an attempt to find such variations. The 11‐year variations produce too few vertical variations to be distinguished from the internal variations and the general noise level, but strong signals were obtained at 13.5‐day periods and some data from periods as long as 6 months. Mantle conductivity profiles are tested in relation to these data, and the K. McDonald model appears quite adequate to the depth sampled by these freq

ISSN:0148-0227    

DOI:10.1029/JZ068i023p06279

年代:1963

数据来源: WILEY