摘要:

Analysis of simultaneous plasma and magnetic field observations by Pioneer 6 suggests, at heliocentric distances of 0.8 to 1.0 AU, significant deviations from Parker's theory: in particular, a radial variation as r−2is estimated for the azimuthal magnetic field componen

ISSN:0094-8276    

DOI:10.1029/GL002i003p00073

年代:1975

数据来源: WILEY

摘要:

The dependence on latitude of the azimuthal component of the interplanetary magnetic field generates a meridional pressure gradient which, in turn, generates a meridional flow. This flow has observable consequences in the equatorial plane, although the meridional velocity itself may be zero in this plane. Analytic estimates of these observables—the mass flux, azimuthal and radial magnetic flux, density, and spiral angle—are made in the range of 1 to 12

ISSN:0094-8276    

DOI:10.1029/GL002i003p00075

年代:1975

数据来源: WILEY

摘要:

There are at least three plasma instabilities associated with the electron heat flux in the solar wind. This letter reports the study of the unstable fast magnetosonic, Alfvén and whistler modes via a computer code which solves the full electromagnetic, linear, Vlasov dispersion relation. Linear theory demonstrates that both the magnetosonic and Alfvén instabilities are candidates for turbulent limitation of the heat flux in the solar wind at 1 A.

ISSN:0094-8276    

DOI:10.1029/GL002i003p00079

年代:1975

数据来源: WILEY

摘要:

Results of model calculations of the Venus ionosphere covering the altitude range from 120 km to 300 km are presented. The chemical scheme and the reaction rates adopted for the model are the same as given in a recent paper byKumar and Hunten[1974], except that the electron temperature dependence of the dissociative recombination rates is taken into account. The calculations were carried out for ‘low’ and ‘high’ atomic oxygen models, corresponding to an [O]/[CO2] ratio of 0.4 percent and 4 percent respectively at 140 km. The results of the calculations agree well in both shape and magnitude with the Mariner 5 and 10 occultation results in the chemically controlled region; at the higher altitudes reasonable agreement with the observation is obtained if diffusive equilibrium and high vertical flow velocities (10 km/sec) are assumed as upper boundaries for the Mariner 5 and 10 conditions, respectively, although solar wind‐ionosphere interactions are the likely controlling mechanism for the Marine

ISSN:0094-8276    

DOI:10.1029/GL002i003p00083

年代:1975

数据来源: WILEY

摘要:

Interplanetary electrons of Jovian origin show minimum intensity and softest energy spectrum when the subsolar point on Jupiter is near the longitude of most frequent non‐Io‐related decametric emissi

ISSN:0094-8276    

DOI:10.1029/GL002i003p00087

年代:1975

数据来源: WILEY

摘要:

A complete sixth‐degree spherical‐harmonic model of the gravitational potential of Mars has been produced from an analysis of Doppler data obtained from the radio tracking of the Mariner‐9 spacecraft for over 200 orbital revolutions. The equipotential surface defined by this model is estimated to be accurate to within 100 m below 60° North Latitude and to within 300 m above. The dominant feature of this surface is a Tharsis‐related bulge which rises nearly two kilometers above the surrounding areas. Gravitational “lows” are found to correspond to the Hellas depression and the Vall

ISSN:0094-8276    

DOI:10.1029/GL002i003p00089

年代:1975

数据来源: WILEY

摘要:

Man‐made alloy spheres (∼300 µm) simulating the compositions of particles found in the lunar soil and weighing approximately 10 mg. are shown to be equivalent, insofar as remanence intensity and demagnetization stability are concerned, to ≳ 1010submicrometer spherical iron particles. The large particles (≳100 µm) not only contain large stable magnetic remanence, but when the polished surfaces of these particles are etched and carefully studied, they provide useful petrogenetic information, imply the mechanism of magnetization, the time‐temperature history, and outline the format for possible paleointensity analysis. The intensity and stability of the remanence in these large spheres is related to the microstructure developed during ra

ISSN:0094-8276    

DOI:10.1029/GL002i003p00093

年代:1975

数据来源: WILEY

摘要:

Measurements of very low‐frequency (VLF) atmospherics were made simultaneously at California and the Island of Hawaii. A third station in the source area in Oklahoma aided in locating each individual lightning event. From the differences in measured field strengths at the two remote stations the transmission loss as a function of frequency was determined for 37 waveform pairs. The average measured transmission loss was then compared to that predicted numerically using several exponential ionospheric conductivity models described by an inverse scale height β and reference height h′ [in the notation ofWait and Spies(1965)]. Based on a weighted least‐squares analysis of the calculated and measured data an appropriate ionospheric conductivity model (β = 0.35 km−1, h′ = 72 km) was chosen which best predicts the measured daytime east‐west transmission loss for a selected frequency band

ISSN:0094-8276    

DOI:10.1029/GL002i003p00096

年代:1975

数据来源: WILEY

摘要:

On June 29, 1974 at 15:14 LST a rocket‐borne cryogenic neutral gas mass spectrometer was flown above Wallops Island as part of the NASA/AFCRL ALADDIN 74 program. The altitude profiles of the signals obtained from argon between 90 and 200 km and ozone between 90 and 110 km are presented. From a comparison of Ar and O3signals, the mixing ratio for O3in the atmosphere is shown to be 10−6or slightly less in the 90–100 km range. At 110 km the mixing ratio drops to around

ISSN:0094-8276    

DOI:10.1029/GL002i003p00099

年代:1975

数据来源: WILEY

摘要:

The line profiles of the sodium D‐lines in the night airglow show considerable broadening which can not be ascribed to temperature alone. Based on this broadening, the known chemistry, and physics of sodium atom production in the upper atmosphere at night, we deduce that excited sodium atoms are most likely produced from the reaction of sodium monoxide and atomic oxygen, and thus find an upper limit for the dissociation energy of sodium monoxide equal to 2.89 eV (determined to a precision of 0.02 eV

ISSN:0094-8276    

DOI:10.1029/GL002i003p00103

年代:1975

数据来源: WILEY