摘要:

This paper reports 101 observations of the solar X‐ray flux in the 8–20 A band. These observations were made by the Solar Radiation 3 satellite from June 29 to November 26, 1961. The fluxes range from a high value of greater than 0.4 erg cm−2sec−1, during a 3+limb flare, to below the limit of detectability, 0.002 erg cm−2sec−1. The intensity of this radiation is correlated with general solar activity and is greatly enhanced during some flares. The intensity is observed to change by a factor of 2 without any apparent change in solar activity. X‐ray enhancements may persist for hours after the end of large flares. Comparison of sudden ionospheric disturbances and the X‐ray enhancements indicates that the spectrum of the X radiation differs from one flare to the next and with time during a gi

ISSN:0148-0227    

DOI:10.1029/JZ068i011p03335

年代:1963

数据来源: WILEY

摘要:

It is shown that the main phase of great magnetic storms is composed of two parts, most clearly characterized by their decay rate: one decays much more rapidly than the other. It is suggested that extraordinarily intense storms are largely due to an abnormal growth of the rapidly decaying part. Because of its rapid decay, the combination with the slow decay part gives a rather sharp change of decay rate, which is commonly seen for great storms. The results are discussed in the light of present theoretical knowledge.

ISSN:0148-0227    

DOI:10.1029/JZ068i011p03345

年代:1963

数据来源: WILEY

摘要:

Prediction equations for the magnetic character figureCiare developed by multiple‐regression procedures for periods 1, 2, 7, and 27 days in advance. The equations use as predictors only past values of Ciitself. The results indicate that the only consistently useful information for prediction is obtained from various combinations of properly weighted predictors 1, 2, 3, 26, 27, 28, 53, 54, and 55 days before the predicted day. The 1‐day prediction equations when applied to a recent set ofCidata (1950–1959) removed all the linearly internally predictable components. The spectrum of the time series remaining after the predictable information was removed closely resembles white noise. This filtered time series is well suited for pilot studies designed to determine the complex underlying physical causes of geomagnetic distur

ISSN:0148-0227    

DOI:10.1029/JZ068i011p03351

年代:1963

数据来源: WILEY

摘要:

Riometer records of cosmic noise absorption obtained at Macquarie Island in the South Pacific and from several stations in the magnetically conjugate area in Alaska demonstrate a high correlation of auroral zone absorption events in the northern and southern hemispheres. Not only the periods of absorption, but also the magnitudes and atructure of the events, are found to be closely, but not exactly, related in the two hemispheres. In this paper both statistical studies and specific absorption events are discussed. The resuts are sufficient to demonstrate that there is a magnetically conjugate area, of narrower dimension in latitude than in longitude. The results are not adequate to indicate whether the occasional breakdown of conjugacy is observed because (a) the riometers were not located at the actual conjugate points, (b) the disturbance phenomena are sometimes nonsymmetrical between the two hemispheres, or (c) the conjugate points are nonstationary.

ISSN:0148-0227    

DOI:10.1029/JZ068i011p03375

年代:1963

数据来源: WILEY

摘要:

Conspicuous micropulsations in the auroral zones with periods from 0.03 to 10 seconds have been studied using data obtained by the Pacific Naval Laboratory and Stanford University during January 1961. For periods less than 0.3 second bursts of oscillations frequently occur superimposed on the background level of ELF noise. These bursts are considered to be of extra‐atmospheric origin because of their conjugate relationships. For periods between 0.3 and 10 seconds four typical classes are defined: (1) Burstlike micropulsations, with quite a wide range of frequencies, which appear at the onset of a polar storm or bay (noise burst). (2) Pearl, beating‐type micropulsations, occurring intermittently so that they form separate bunches (PP). (3) Continuous micropulsations, typically found in the forenoon, with periods from 0.3 to 3 seconds (CPsp). (4) Continuous micropulsations, typically found in the afternoon, with periods from 3 to 10 seconds (CPlp). Not every polar storm or bay is accompanied by noise bursts. Noise bursts are found only at the onset of polar storms or bays occurring around or before local midnight. Separate bunches of pearl, beating‐type micropulsations are attributed to a bouncing agent whose bouncing period of a few minutes can be determined from the time lag of their occurrences in conjugate areas. If the agent repeatedly excites micropulsations, they are continuous, although sometimes a correlation analysis between conjugate points indicates a bouncing period similar to that of PP. Possible physical mechanisms are suggested for these four classes of micropulsa

ISSN:0148-0227    

DOI:10.1029/JZ068i011p03383

年代:1963

数据来源: WILEY

摘要:

The amplitude of the 20‐Mc/s signal from the satellite Explorer 7 was recorded at Auckland from November 1960 to August 1961. Variations in the fading period are used to study the irregularities that occur in the electron density of the ionosphere. Relations are given for calculating the size and density of these irregularities directly from plots of the fading period of the received signal. Results for 770 irregularities, observed at all times of day, with sizes from 5 to 500 km, are presented. The number with sizes betweenSandS+ΔSwas approximately proportional to ΔS/S. The electron content of the irregularities, measured vertically, was generally between 0.03 and 4 per cent of the total electron content of the ionosphere, with a median value of 0.25 per cent. The density at the center of the irregularities differed from the density of the background ionization by about 1 per cent for the smaller and 10 percent for the largest ones. The irregularities were not elongated in the direction of the magnetic field, but occurred in the form of horizontal slabs with a vertical thickness equal to about one‐fifth of the horizontal dimension. The fact that most irregularities larger than 50 km occurred in series of three or more similar ones suggests that they are caused by a wave of disturbance propagated through the ionosphere with a wavelength of about 1

ISSN:0148-0227    

DOI:10.1029/JZ068i011p03399

年代:1963

数据来源: WILEY

摘要:

The shapes of the D lines, integrated over the solar disk, have been observed from Madison, Wisconsin, United States, for a year, with spectroscopic resolution sufficient to resolve the ground‐state hyperfine structure of sodium in telluric absorption. An annual upper‐atmosphere sodium abundance plot shows an autumn maximum of (8±2)× 09atoms/cm2and no detectable sodium from April to August 1961. The observations in a single day show definite, apparently random, variations. Several other telluric absorption lines in the neighborhood are listed. Out to about 220 mK or 13 ppm from the line centers, the profiles of intensityI(relative to the continuum), corrected for telluric absorption, follow the expressionI=I0exp (|x|/xe)A, withI0xeAD1(λ5896) 0.0495 217 mK or 12.8 ppm 2.14 ±0.0010 ±6 mK ±0.4 ppm ±0.10 D2(λ5890) 0.0444 228 mK or 13.4 ppm 2.16 ±0.0010 ±6mK ±0.4 ppm ±0.12The wave numbers of the D lines, corrected for the relative motion of the earth, show a relative red shift δσ/σ = (−2.7 ± 0.4) × 10−6, indicating that the net effect of the Lindholm shift and convection currents is small compared with the computed relative gravitat

ISSN:0148-0227    

DOI:10.1029/JZ068i011p03419

年代:1963

数据来源: WILEY

摘要:

This report concerns measurements of oxygen microwave absorption line widths and intensities of the significant lines between 58 and 62 kilomegacycles per second. These measurements were made at pressures ranging from 0.25 to 20.6 mm of Hg. The values obtained for the line widths of these eight lines ranged from 1.39 to 1.85 Mc/s/mm of Hg. Their measured intensities were from 4.73 to 8.85 db/km. Values for N2/O2broadening ratios were determined for this pressure range for the two lines at 61.1 and 61.8 kMc/s. Correlation with the results of other investigators is shown.

ISSN:0148-0227    

DOI:10.1029/JZ068i011p03431

年代:1963

数据来源: WILEY

摘要:

This paper gives the density profile versus altitude from 95 to 130 km obtained from drag measurements made directly from within a falling sphere. In the test, an inflatable sphere, 2.74 meters in diameter, is ejected somewhere between 80 and 100 km during the ascent of an Aerobee 150 rocket. At the center of the sphere, supported by an inflated cylindrical strut, are the measuring instruments and the necessary electronics to telemeter the information continuously throughout the flight. The main sensors are linear accelerometers aligned to measure theX,YandZcomponents of acceleration of the sphere from which total drag is obtained. From ejection altitude, the sphere continues to an altitude of approximately 250 km on what is, except for drag, a free‐fall trajectory. Measurements of drag acceleration obtained by this method are supplemented by measurements of velocity and position obtained by tracking system

ISSN:0148-0227    

DOI:10.1029/JZ068i011p03437

年代:1963

数据来源: WILEY

摘要:

A strong manifestation of the electrode effect is seen on the New Mexico semidesert during nighttime periods of very low wind velocity. A filter space‐charge apparatus, installed below ground level with its intake flush with the surface, makes it possible to see strong enhancement of space‐charge density during these periods. Peaks are sometimes higher than 4000 elementary charges cm−3. The layer of enhanced space charge is shallow; it is not much in evidence at 65 cm above the ground. Parcels of negative space charge frequently are registered at 50, 65, and 80 cm when positive space charge of more than 1000 elementary charges cm−3is present at ground level. Space‐charge density at ground level is highly variable during these periods, and there is a strong inverse correlation between wind velocity and space‐charge density, especially when the wind velocity is less than 1 m sec−1Wind‐correlated turbulence, significant in the diffusion of space charge, evidently is present in winds of only a few tenths m sec−1. Winds of more than 1 m sec−1largely eliminate the space‐charge enhancement, and it is not seen wh

ISSN:0148-0227    

DOI:10.1029/JZ068i011p03451

年代:1963

数据来源: WILEY