摘要:

An explanation of the charging mechanism operating in the B‐ring of Saturn is offered in terms of a Clausius‐Mossotti type polarization catastrophe based on the peculiar ferroelectric properties of ice. Polarization charges of 400 Coulombs and electrostatic energies of 3 · 109Joules are estim

ISSN:0094-8276    

DOI:10.1029/GL010i001p00001

年代:1983

数据来源: WILEY

摘要:

The ring plane event detected by the Voyager 1 and 2 Planetary Radio Astronomy experiment is distinct from Saturn kilometric radiation (SKR) and from Saturn electrostatic discharges (SED). It consists of radio noises recorded only during Saturnian ring plane crossings. Several models are tested. The electrostatic noise on the antennas resulting from the passage of electrons and ions near the antennas (quasi‐thermal noise) leads to order of magnitude much lower than the observed values. Shot noise due to electrons and ions collected and/or emitted by the antennas and spacecraft can explain the noise recorded during Saturn Voyager 1 ring plane crossing and partly what is observed in the case of Voyager 2. For this latter event we must introduce the shot noise due to grain impacts. A quantitative approach of this process gives an estimation of the dust size ∼ 2.3 µm just outside the G

ISSN:0094-8276    

DOI:10.1029/GL010i001p00005

年代:1983

数据来源: WILEY

摘要:

Voyager 1/2 observations are used to confirm and quantify the unusual bluntness of the dayside Saturn magnetopause suggested by the earlier Pioneer 11 measurements. Once corrected for variations in solar wind pressure, the Saturn observations are found to indicate a magnetospheric radius in the terminator plane equal to 1.8 times the nose distance. This ratio is 30% greater than the terrestrial value and is corroborated by the very blunt shape of the Saturn bow shock and large width of the forward magnetosheath. Possible causes and ramifications of these results for the solar wind interaction with Saturn are discussed.

ISSN:0094-8276    

DOI:10.1029/GL010i001p00009

年代:1983

数据来源: WILEY

摘要:

Occurence of a prominent peak in the ion energy spectrum at energies of 0.1 to 0.7 MeV is observed by the IMP‐8 spacecraft during an energetic particle burst in a plasma “dropout” interval at about 37 Rein the earth’s magnetotail. This unusual characteristic in the spectrum is detected for about 2 minutes. By fitting the observed ion spectra to a drifting Kappa distribution, it is found that the ion population can be described as a hot beam with number densities 4 × 10−7to 5 × 10−4cm−3and temperatures 15 to 45 keV, jetting tailward at speeds of 3500 to 7000 km/s. The energy flux density associated with the beam can be as high as 8 × 10

ISSN:0094-8276    

DOI:10.1029/GL010i001p00013

年代:1983

数据来源: WILEY

摘要:

The coupling of the shear Alfven wave and the drift compressional wave is studied in a two‐component plasma. It is shown that with the incorporation of ▽B particle drift in the dispersion equation the cold component in addition to reducing the Alfven speed to create an unstable drift compressional wave, also plays an important role in the coupling of the mode to the shear Alfven wave resulting in major modification of the instabil

ISSN:0094-8276    

DOI:10.1029/GL010i001p00017

年代:1983

数据来源: WILEY

摘要:

Recent determinations of O2absorption cross sections in the Herzberg continuum, obtained from in situ solar irradiance measurements, have shown that the corresponding laboratory values might be overestimated by 30 to 50 percent. The change in the stratospheric composition due to such a reduction in these cross sections has been calculated by means of a steady state one dimensional chemical model. An accurate determination of the O2absorption spectrum in the 200‐220 nm range is required since the distribution of several trace species is very sensitive to the atmospheric transmissivity in this wavelength regio

ISSN:0094-8276    

DOI:10.1029/GL010i001p00020

年代:1983

数据来源: WILEY

摘要:

Monthly mean stratospheric temperatures at 50‐ and 30‐mbars between 10° and 30°N for the years 1964‐1981 are compared with data for 1982. It is shown that the 30‐mbar temperatures at 10°N increased in July, August, September, and October 1982 to values well above those shown for the previous 18 years. We believe this to be caused by aerosols produced from the recent eruptions of El Chichon (17.33°N, 93.2°W) on April 4, 1982. This is the first time that a direct connection between an increase of stratospheric temperatures and an increased aerosol load has been established

ISSN:0094-8276    

DOI:10.1029/GL010i001p00024

年代:1983

数据来源: WILEY

摘要:

Intense stratospheric dust layers have been observed with a lidar at L'Aquila (42°N, 13°E) during the months of July and August 1982. These features were located at 22‐26Km with a maximum scattering ratio of 13. In one occasion a layer was also observed at 32Km. Maximum integrated scattering is of the order of 0.001 sr−1. The almost daily frequency of the observations has revealed an unusually fast decrease of the altitude of the layers with an apparent velocity of 0.2‐0.3Km/day. This pattern is repeated in both the high altitude layers observed. It is speculated that this effect could be attributed to the zonal distribution of the dust which in turn could depends on dust formation

ISSN:0094-8276    

DOI:10.1029/GL010i001p00027

年代:1983

数据来源: WILEY

摘要:

From June 1980 to December 1981 lava dust samples from the eastern slope of Mt. Etna were periodically collected in order to estimate the volcanogenic contribution to environmental pollution. The heavy metal composition of these dusts suggests that this volcano does not basically modify the surrounding basaltic soil, but is a polluting agent of the remote Sicilian environment. In the lava‐ash the level of leachable elements is negligible. Furthermore, the amount of heavy metals enriched in volatiles relative to that in ash falling to at ground‐level appears to be signific

ISSN:0094-8276    

DOI:10.1029/GL010i001p00031

年代:1983

数据来源: WILEY

摘要:

High resolution Fourier transform spectra of the atmosphere in the 2850 ‐ 2950 cm−1region have been recorded from the ground using the sun as a source. For the first time, many NO2absorption peaks belonging to the ν1+ ν3band and its associated hot band ν1+ ν2+ ν3− ν2have been located. Among them, 13 well isolated features have been used to determine NO2vertical column densities. Indeed, from the analysis of 4 spectra recorded at air masses of 10.7, 5.4, 3.1 and 10.8, that is for the 3 first ones just after sunrise and in the early morning and for the last one just before sunset, vertical column densities of 1.84 ± 0.34, 1.80 ± 0.28, 1.74 ± 0.44 and 3.24 ± 0.46 1015molecule.cm−2have been obtained. The good absolute accuracy of these results is due to the use of several lines having a wide enough range of intensities and of lower st

ISSN:0094-8276    

DOI:10.1029/GL010i001p00035

年代:1983

数据来源: WILEY