摘要:

The abrupt increases in radio‐wave absorption that accompany the breakup of visual auroral forms have been studied using the data from several stations in Alaska and by the multiple‐frequency technique at College. Such abrupt increases in absorption were found to be somewhat localized in space and to occur most frequently around local midnight. The multiple‐frequency technique indicates an abundance of high energy particle influx during abrupt e

ISSN:0148-0227    

DOI:10.1029/JZ070i001p00089

年代:1965

数据来源: WILEY

摘要:

Photoionization and total absorption cross sections have been measured for CO2, CO, Ar, and He at the wavelengths in the region 1040 A to 300 A which correspond to intense solar emission lines. The wavelength resolution, determined from the measured width of each of the spectral lines generated within the light sources, was in the range 0.04 to 0.1 A.

ISSN:0148-0227    

DOI:10.1029/JZ070i001p00099

年代:1965

数据来源: WILEY

摘要:

The evaluation of improved measurements of atmospheric absorption characteristics at nine wavelengths of solar extreme ultraviolet radiation, conducted on July 10, 1963, at 1004 A.M. over White Sands, N.M., leads to data on the vertical distribution of N2, O, and O2which are tabulated for altitudes from 150 to 220 km. These data may be fairly typical for the thermosphere at moderate northern latitudes, a zenith angle of about 30°, and for most of July 1963, a month of generally quiet solar conditions

ISSN:0148-0227    

DOI:10.1029/JZ070i001p00105

年代:1965

数据来源: WILEY

摘要:

A method by which the recombination coefficient of the nighttimeFregion of the ionosphere can be determined, previously applied to mean monthly Puerto Rico true height profiles, has been applied to results from six sounding stations at different latitudes. Further work has been done on the effect of various assumptions used in the analysis. No large latitude dependence of the recombination coefficient at 300 km was observed. A large seasonal effect was found, however. The analysis has been extended to the calculation of vertical diffusion and total transport velocities, and a determination of the diffusion coefficient effective in the nighttimeFregion was obtained. The diffusion coefficient was found to befor current models for the neutral atomic oxygen density. Vertical drift velocities determined from mean monthly profiles derived from hours for whichKρwas less than 4.5 were found to be generally lower than 10 m/sec

ISSN:0148-0227    

DOI:10.1029/JZ070i001p00113

年代:1965

数据来源: WILEY

摘要:

Observations of the electron density, electron temperature, and ion temperature were made over the height range 240–750 km vertically above Millstone Radar Observatory on July 19–21, 1963. The technique employed for these measurements is the incoherent backscatter method. The eclipse occurred on the afternoon of July 20 and caused a large rapid decrease in the electron temperature at all heights and a subsequent recovery. The ion temperature was seen to change at all heights almost equally rapidly, though by a smaller amount. These changes in temperature caused a rapid reduction in the value for the diffusive equilibrium scale height. As a consequence, ionization moved downward and the density athmaxincreased, though at altitudes above 425 km it decreased. The total electron content of the region under study was about 7×1012electrons/cm3at the commencement of the event but had declined to about 6×1012electrons/cm2by the time point of last contact was re

ISSN:0148-0227    

DOI:10.1029/JZ070i001p00131

年代:1965

数据来源: WILEY

摘要:

The ion temperature of the upper atmosphere at local noon in the region from 100 to 160 km has been measured directly by means of an ion trap. The ion temperature is expected to be the same as that of the neutral particles, since analysis shows that the thermal relaxation time of ions to neutrals is shorter than that of ions to plasma in the above height range. Above 120 km the experimental temperature profile contains what appears to be a wave‐like temperature variation superimposed on an otherwise reasonable thermosphere profile. The peak‐to‐trough amplitude of the temperature variation is 200°K, and the average wavelength is approximately 12 km. The thermosphere temperature profile parallels predicted thermosphere profiles but may be systematically high. At and below 115 km the shape of the profile deviates from predicted profiles. The temperature is high and increases downward; this increase may be caused by aerodynamic heating of the ions before they enter the trap.The amplitude of the wave‐like temperature variation is consistent with that expected from a gravity wave producing a horizontal wind velocity of 150 m/sec. However, the vertical wavelength is smaller than that believed possible for gravity waves in the altitude interval of interest. On the other hand, measured total extreme ultraviolet energy is insufficient to maintain a quasi‐steady‐state temperature profile of the sh

ISSN:0148-0227    

DOI:10.1029/JZ070i001p00143

年代:1965

数据来源: WILEY

摘要:

Midlatitude night airglow and particle fluxes have been measured simultaneously with a Nike‐Apache rocket fired from Wallops Island, Virginia, near midnight and new moon in July 1964. The rocket carried two photometers, three Geiger counters and two scintillators, and two magnetometers as aspect sensors. The experiment conclusively demonstrated with three independent techniques that midlatitude 5577 A night airglow is not excited by charged particle bombardment as it is in auroras. First, the intensity of 3914 A above 85 km was measured to be 5 rayleighs or less, whereas if energetic particles had produced the 400 R of 5577 A observed they should have also produced about 200 R of 3914 A, or more than forty times what was observed. Second, the altitude profile was measured with high precision, and with its peak at (94.5±0.3) km and its half‐width of (5.8±0.3) km it was shown to be much narrower than it would be if produced by particle fluxes of various energy spectrums and pitch‐angle distributions. Third, the actual particle fluxes were measured, and they could have produced much less than 1 R of 5577 A around the altitude where it was brightest. The results therefore prove that less than approximately 3% of midlatitude 5577 A night airglow can be termed a permanent aurora. The 3914 A photometer measured 5 R emitted above 85 km, but a zenith‐equivalent brightness of 10 R when it viewed the emission edge‐on. The difference of 5 R is shown to be just that which would be caused by cosmic radiation at altitudes below 30 km. The particle fluxes are shown to be somewhat less than the precipitated fluxes measured several years previously with satellites. A comment is made on the contamination of some measurements of galactic X rays by such precipitated electrons and

ISSN:0148-0227    

DOI:10.1029/JZ070i001p00161

年代:1965

数据来源: WILEY

摘要:

The energy that is deposited in the ionosphere by internal atmospheric gravity waves propagating upward from below is assessed on the basis of recent observational data. The implied heating rates are found to range from 10°K/day (near the 95‐km level) to 100°K/day (near 140 km), and they therefore compete with solar radiation as the primary source of heating in the ionosphericEregion. The tidal input may be comparable, but its height of deposition is more difficult to assess. The residual wave energy that reaches theFregion carries a flux that may exceed 10−4watt/m2, and so it may play a significant role in determining the heat budget of these higher levels. The waves should be accompanied by reversible temperature fluctuations of ±10°K and more, low in tneEregion, and they may therefore account for irregular temperature structure that has been r

ISSN:0148-0227    

DOI:10.1029/JZ070i001p00177

年代:1965

数据来源: WILEY

摘要:

In a recent rocket flight electron attachment rates were measured at several altitudes in the range of 45 to 65 km. Regions of excess electrons were created by the emission from the rocket of strong pulses of electromagnetic energy at the electron gyrofrequency. Each such disturbance produced cross modulation of a sensing wave that was transmitted from the launch site and detected at the rocket. A model of the disturbance as a small bubble‐like region of excess electrons surrounding the rocket is shown to be capable of producing the observed form of cross modulation. Using this analysis it is possible to determine the electron removal rate from the cross modulation wave shapes. The data indicate a two‐body attachment proc

ISSN:0148-0227    

DOI:10.1029/JZ070i001p00185

年代:1965

数据来源: WILEY

摘要:

Sudden impulses in the earth's magnetic field were analyzed by the construction of vector diagrams of the total horizontal disturbance vector ΔH fromDandHrapid‐run magnetograms for observatories all over the world. At high latitudes the si field was found to be elliptically polarized during the first few minutes of the disturbance. From a comparison of the morphologies of ssc's and si's, it was concluded that si's are also caused by fluctuations in the solar wind energy density and that the perturbations are propagated to the earth's surface by hydromagnetic wav

ISSN:0148-0227    

DOI:10.1029/JZ070i001p00191

年代:1965

数据来源: WILEY