摘要:

Introduction. A decade ago it was commonly believed that the hydrostatically supported atmosphere of the earth decreased in density to very low values within a few hundred kilometers of the earth's surface. This view was based on assumed thermodynamic temperatures of only a few hundred degrees, applied to the oxygen and nitrogen atoms which dominate at the heights concerned. Similar considerations indicated a corresponding confinement of the overlying exosphere—of the region, that is, where the constituent neutral atoms are free from significant collisions with one another, and where instead their motions follow ballistic trajectorie

ISSN:0148-0227    

DOI:10.1029/JZ065i009p02563

年代:1960

数据来源: WILEY

摘要:

The view is presented that the outer portion of the earth's ionosphere, through which radio whistlers propagate, has its origin in the earth's atmosphere rather than in interplanetary space. The outer portion of the earth's neutral‐particle exosphere is dominated by neutral atomic hydrogen which is escaping steadily from the earth's atmosphere. Some of this neutral atomic hydrogen reacts with atomic oxygen ions near the base of the exosphere, giving rise to hydrogen ions. Diffusive equilibrium is the dominant factor controlling the relative concentration of ions and neutral particles near the base of the exosphere. At higher levels, the geomagnetic field exerts an influence in that it causes the ions and electrons to rotate with the earth, and the centrifugal force modifies the force of gravitational attraction appreciably. The ion electron plasma through which the radio whistlers propagate is hydrostatically supported within the magnetic tubes of forc

ISSN:0148-0227    

DOI:10.1029/JZ065i009p02571

年代:1960

数据来源: WILEY

摘要:

The main components of the earth's exosphere are neutral oxygen, neutral hydrogen atoms, ionized oxygen, and ionized hydrogen. The position of the base of the exosphere is established at an altitude of 530 km, from an analysis of density data obtained from satellite drag observations. The relative distribution of both neutral oxygen and neutral hydrogen is derived from a theory of the exosphere. The normalization of oxygen is accomplished by means of satellite drag data. The normalization of hydrogen is accomplished by means of the Lyman‐α technique of Johnson, Friedman, and Tousey. The distribution of ionized oxygen can be established jointly from the rocket measurements of Berning and from an analysis of radiation belt data obtained from satellites. They give a consistent picture of ionized oxygen becoming the most important constituent of the atmosphere at about 1500 km. The distribution of ionized hydrogen is only imperfectly kno

ISSN:0148-0227    

DOI:10.1029/JZ065i009p02577

年代:1960

数据来源: WILEY

摘要:

Accurate measurements show that the variation of whistler dispersion with frequency is of the form predicted by Storey for an exosphere consisting largely of ionized hydrogen. From these measurements the height at which protons become sufficiently numerous to affect the whistler dispersion is estimated to be 1000 km.

ISSN:0148-0227    

DOI:10.1029/JZ065i009p02581

年代:1960

数据来源: WILEY

摘要:

Whistlers appear to propagate in columns of enhanced ionization aligned with the earth's magnetic field. From nose whistlers a value of 100 electrons/cm3is calculated at 5 earth radii.

ISSN:0148-0227    

DOI:10.1029/JZ065i009p02583

年代:1960

数据来源: WILEY

摘要:

This paper presents the results of an experiment to measure the electron density above the ionosphere. The experiment utilized two coherent signals, one VHF and one UHF, transmitted from the Explorer VI satellite. The evidence of our data is that the electron concentration in the vicinity of the satellite, 18,000 km above the earth, was unusually high, of the order of 104electrons/cm3. However, the results were influenced by unexpectedly high correction factors and possibly by an intense world‐wide magnetic storm that occurred during the measurement perio

ISSN:0148-0227    

DOI:10.1029/JZ065i009p02585

年代:1960

数据来源: WILEY

摘要:

At 0700 EST, November 10, 1959, a sounding rocket was launched from Wallops Island, Virginia, for the purpose of measuring electron densities in the high ionosphere. A continuous‐wave (CW) technique was employed in the measurement, and the dispersive Doppler effects at 37 and 148 Mc/s were observed. Data are presented indicating derived electron densities to 1500 km for the up‐leg of the rocket trajectory. The decrease in electron density above theF2maximum indicates a scale height of only 30 km at 270 km but a linear scale‐height gradient of 0.45 km/km from 270 to 7

ISSN:0148-0227    

DOI:10.1029/JZ065i009p02589

年代:1960

数据来源: WILEY

摘要:

Evidence for a gradient of scale height in theFregion is shown, and discussed in relation to a simple Chapman model of theFregion abovehmaxF2. It is suggested that a similar model, but allowing for a scale‐height gradient, may give somewhat better agreement with recent observation

ISSN:0148-0227    

DOI:10.1029/JZ065i009p02595

年代:1960

数据来源: WILEY

摘要:

Measurements are given of electron‐density distributions above the maximum of theFlayer from seven rocket flights. The missiles used for these experiments had large horizontal velocity components, and a matrix method was employed to derive the profiles, account being taken of horizontal gradients, refraction, and the varying ray path zenith angles in the ionosphere. Two methods of measuring ionospheric dispersion were compared: Faraday rotation, and a method using the difference between the apparent positions of the missile obtained by two tracking systems operating on different frequencies. Faraday rotation measurements at two receiving stations and on two frequencies were compared to check the horizontal gradient program and the polarization of the rocket antenna. The implications of the results are discussed in terms of the structure of the layer and its diurnal variatio

ISSN:0148-0227    

DOI:10.1029/JZ065i009p02597

年代:1960

数据来源: WILEY

摘要:

A procedure for determining the ionospheric electron content up to the height of an active satellite from Doppler data is developed. The equations derived from first‐order theory are discussed and corrected separately for earth curvature, large refraction, off‐zenith orbit, vertical satellite motion, horizontal ionospheric variations, and the effects of the earth's magnetic field. The methods were developed initially for use with the harmonic radiations from satellite 1958δ2at frequencies of approximately 20 and 40 Mc/s, but may be adapted to other harmonic frequency ranges. The results obtained by applying this method to the experimental data from 1958δ2are presented in p

ISSN:0148-0227    

DOI:10.1029/JZ065i009p02601

年代:1960

数据来源: WILEY