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991.
Ambipolar diffusion is discussed for the case of a weakly-ionized, multicomponent plasma. Shortcomings of some of the previous formulations of this problem are pointed out. In particular, it is shown that the polarization electrostatic field acts to couple the motion of the various ions with the result that the diffusion velocity of each ion depends on the density gradients of all the ions. 相似文献
992.
Cosmos 316 (1969-108A) was launched on 23 December 1969 into an orbit with an initial perigee height of 154 km at an inclination of 49.5° to the equator. Being very massive, Cosmos 316 had a longer lifetime than any previous satellite with such a low initial perigee: it remained in orbit until 28 August 1970. Because of its interest for upper-atmosphere research, the satellite was intensively observed, and accurate orbits are being determined at RAE from all available observations. Using perigee heights from the RAE orbits so far computed, and decay rates from Spacetrack bulletins, 102 values of air density have been obtained, giving a detailed picture of the variations in density at heights near 150 km between 24 December 1969 and 28 August 1970. The three strongest geomagnetic storms, on 8 March, 21 April and 17 August 1970, are marked by sudden increases in density of at least 23, 15 and 24 per cent respectively. With values of density extending over eight months, it is possible for the first time to examine a complete cycle of the semi-annual variation at a height near 150 km: the values of density, when corrected to a fixed height, exhibit minima in mid January and early August; at the intervening maximum, in April, the density is 30 per cent higher than at the minima. 相似文献
993.
Doreen M.C. Walker 《Planetary and Space Science》1977,25(4):337-342
In analysing the orbit of Ariel 1 to determine upper-atmosphere winds, it was observed that the orbital inclination underwent a noticeable perturbation in November 1969 at the 29:2 resonance with the Earth's gravitational field, when the satellite track over the Earth repeats every 2 days after 29 revolutions. The variations in the inclination and eccentricity of the orbit between July 1969 and February 1970 have now been analysed, using 35 US Navy orbits, and fitted with theoretical curves to obtain lumped values of 29th-order harmonic coefficients in the geopotential. 相似文献
994.
The visible airglow photometer on the Atmosphere Explorer C Satellite has been used to compare the calibrations of a number of ground-based airglow observatories. Discrepancies between different ground stations as large as a factor of six have been revealed. Efforts to account for these discrepancies have resulted in the discovery of differences as large as a factor of 2 in the standard light sources in use at different observatories. The participation of additional observatories in the intercomparison of standard sources is solicited. The project has also led to the discovery of a source of error that can amount to another factor of 2 in the procedure used to calibrate many airglow instruments. In the course of the project detailed maps, based on satellite data, have been made of the galactic and zodiacal light background at a number of wavelengths, and a substantial source of contaminating emission has been discovered in the satellite data; the contamination appears to result from interaction of the spacecraft and the atmosphere at altitudes below 170 km. 相似文献
995.
Experimental results from Arecibo indicate that on the average the height integrated F-region Pedersen conductivity is slightly greater than the height integrated E-region Pedersen conductivity, while the height integrated Hall conductivity exceeds either of the Pedersen conductivities by a factor of about 2. However, the conductivities can differ substantially from the average values on any given night. 相似文献
996.
Doreen M. C. Walker 《Planetary and Space Science》1975,23(12):1573-1579
Explorer 1, 1958α, ths first U.S. artificial satellite, was launched on 1 February 1958 and remained in orbit for 12 years. In this paper theoretical curves have been fitted to the values of inclination, giving three values of the average atmospheric rotation rate at heights of 350–400 km, and latitudes 0–20°:
Feb 1958 to mid 1960 | 1.5 rev/day | |
Mid 1960 to Dec 1967 | 1.2 rev/day | |
Jan 1968 to Mar 1970 | 1.3 rev/day |
109C? | 109S?l,14 | |
- | - | - |
14 | ?38.5 ±2.9 | ?7.8 ±2.2 |
15 | 4.5 ±1.1 | ?23.8 ±0.3 |
16 | ?22.3 ±3.6 | ?36.0 ±3.8 |
17 | ?15.0 ±2.6 | 16.8 ±1.2 |
18 | ?24.0±4.9 | ?3.2 ±3.7 |
19 | ?1.6 ±2.8 | ?7.6 ±1.0 |
20 | 8.8 ±5.8 | ?15.4 ±4.6 |
21 | 18.2 ±3.6 | ?10.6 ±1.9 |
22 | ?14.5 ±8.1 | 9.9 ±6.4 |
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