摘要:

Observations of 8‐ to 14‐µ flux from diametric scans of Venus with the 200‐inch Hale telescope have been made. The reduced data indicate an unexpected brightening near the Cytherean limb. The data show a more complicated atmospheric structure than postulated by published models. Horizontal inhomogeneity of the emission complicates the interpre

ISSN:0148-0227    

DOI:10.1029/JZ071i011p02693

年代:1966

数据来源: WILEY

摘要:

A comparison of observations with several earth satellites reveals that the inner edge of the outer radiation zone of electronEe>1.6 Mev intensities has moved outward fromL≃ 2.2 in mid‐1958 toL= 3.0 in late 1964. This outward motion in the outer radiation zone occurs during the declining phase of solar activity cycle 19 and strongly suggests a systematic change of the average value of one or more of the solar wind parameters over this time per

ISSN:0148-0227    

DOI:10.1029/JZ071i011p02697

年代:1966

数据来源: WILEY

摘要:

Trajectories of charged particles in a static dipole magnetic field are considered for the case of small equatorial pitch angles under the assumption of the conservation of the adiabatic invariants. By physical reasoning, higher order correction terms to the conventional first invariant sin2α/B, are deduced. These terms, being functions of particle mass, velocity, and gyration angle around the field line, produce the following effects in the radiation belts: (1) Near the equatorial plane at largeL, the oscillation of the proton pitch angle at the cyclotron frequency is significant. For example, atL= 10, the 150‐kev proton pitch angle oscillates by as much as 10°. (2) At low altitudes the pitch angular distribution of protons accelerated near the equatorial plane is limited to certain general forms. Results of detailed calculations are presen

ISSN:0148-0227    

DOI:10.1029/JZ071i011p02701

年代:1966

数据来源: WILEY

摘要:

The effect of density fluctuations on the radar determination of total electron content is studied in terms of the recent measurement of average cislunar density. It is shown that a ‘grating effect’ is possible, and that severe modifications in the propagation constants occur if the incident wave is scattered by coherent plasma oscillations for which the electrostatic wavelength is near half the radio wavelength. Evidence suggesting that such plasma oscillations may be present in the magnetosphere is discus

ISSN:0148-0227    

DOI:10.1029/JZ071i011p02709

年代:1966

数据来源: WILEY

摘要:

The scattering of electrons in a spatially homogeneous magnetic field‐free stable plasma by ion and electron plasma waves excited by suprathermal particles is considered using a test‐particle approach. A previously derived theory is modified and extended to the case of ion‐waves propagating in a current bearing plasma. The results are applied to electrons in the earth's magnetosphere and in the transition zone between the magnetosphere and the interplanetary medium, where the geomagnetic field is weak in the sense that Ω2« ω2pe(Ω =eB/mc; ω2pe= 4πne2/m). It is found that interaction with electron plasma oscillations is competitive with whistlers in scattering suprathermal electrons, and that ion waves are the dominant mechanism for the diffusion of subthermal electrons across the magnetopause and the

ISSN:0148-0227    

DOI:10.1029/JZ071i011p02715

年代:1966

数据来源: WILEY

摘要:

A method for detecting and measuring collisionless magnetohydrodynamic (MHD) shock waves propagating in interplanetary space using bistatic‐radar transmissions from earth to a spacecraft is suggested. The shock wave is represented by a one‐dimensional flow model in which the magnetic field is taken to be aligned normal to the plasma flow. The method basically involves performing multichannel phase and group path measurements of the columnar electron density between transmitter and receiver. Detection is accomplished from observation of typical shock signatures on the time response of the measurements. The magnitudes of the time response provide information for establishing a number of magnetoacoustic shock parameters characterizing the shock intensity. In addition, the proposed measurements under suitable conditions can possibly detect shock‐density oscillations as well as provide information needed to help resolve certain fundamental questions concerning the structure of collisionless MHD shock

ISSN:0148-0227    

DOI:10.1029/JZ071i011p02729

年代:1966

数据来源: WILEY

摘要:

Ultraviolet emissions in the 1000–1350 A range were measured from a rocket launched into an aurora from Fort Churchill. Intense radiation in these wavelengths was detected. The emissions are believed to be from atomic oxygen and neutral molecular nitroge

ISSN:0148-0227    

DOI:10.1029/JZ071i011p02739

年代:1966

数据来源: WILEY

摘要:

The sources of error in previous methods are discussed, and a different method that minimizes them is presented. The theory is discussed with the objective of designing improved apparatus to make accurate routine height measurements. Measurements have been made of the height of the 5577 A nightglow layer obtaining an average height of 97±3 km

ISSN:0148-0227    

DOI:10.1029/JZ071i011p02743

年代:1966

数据来源: WILEY

摘要:

Results are presented of an analysis of the physical characteristics of 320 very small meteors (mean mass: ∼10−4g) observed under the Harvard Radio Meteor Project. The meteors have been detected from at least three different stations. Each station yields instantaneous values of the velocity υ and of the electron line densityqin the trail that permit the determination of the mean deceleration and a sketch of the ionization curve. In turn, from the determination of the total ionization produced by the meteor we compute its initial massm∞. It is therefore possible for the first time to derive values for the density and ablation coefficient of radio meteors. Analysis of the magnitudes and heights reveals the common occurrence of fragmentation among the meteors of the sample. The maximum electron line densityqmis found to be proportional tom∞0.7υ∞3instead of tom∞υ∞4, as predicted by the classical theory. Moreover, the observedqmis systematically larger than its theoretical value by a factor of 2. Consequently, the observed magnitudes are 0.8 magnitude brighter than theoretically expected. The height of maximum ionization is 2.5 km higher than the theoretical value; its dependence on velocity is not too anomalous. The average length (10 km) and duration (0.3 sec) of the meteors of the present sample are only 40% of the expected theoretical values. The computed densities are affected by large random errors, due principally to the inaccuracy of the heights. The median value, 0.8 g/cm3, confirms the fragile structure of these particles. The ablation coefficients are remarkably lower than those of faint photographic meteors and show a strong depend

ISSN:0148-0227    

DOI:10.1029/JZ071i011p02749

年代:1966

数据来源: WILEY

摘要:

A significant summertime micropulsation band at ∼4‐sec period is revealed in the several years of continuous micropulsation recording at College. The band contains mainly Pc‐type activity, but is also seen in certain weak Pi 1 bursts. The intensity of the band is greatest in afternoon at College and has a positive correlation withKpin afternoon. A small diurnal variation in band midperiod was observed, with periods near 4 sec in day and near 3 sec at night. The 4‐sec events are usually less well structured than higher frequency pearl‐type events, and the frequency‐time elements are often irregularly spaced. The possibility exists that the 4‐sec band is due to the principal exosphe

ISSN:0148-0227    

DOI:10.1029/JZ071i011p02763

年代:1966

数据来源: WILEY