摘要:

The theory and operation of a Gerdien condenser in a collision‐controlled regime is reviewed. Its operation under supersonic flow conditions is then presented and the results of calibration of the instrument in a wind tunnel are discussed. The theory of mobility is reviewed and the importance of a mean‐free‐path or mean‐free‐time model between ion‐neutral collisions is discussed. Experimental positive ion mobility data are presented and compared with the data ofRose and Widdel[1972] and the extrapolated values of small ion laboratory results. The assumption of chemically frozen flow is then considered concerning the equilibrium distribution of the water cluster ions and their temperature‐dependent decomposition rates. It is shown for flow at Mach 3 that when the shock is detached the dominant cluster ions are not frozen. However, when the shock is swallowed the H+(H2O)3ion is frozen at all altitudes above 40 km and the H+(H2O)4ion is frozen above 65 km. The predicted mobility of the dominant positive ions, i.e., H+(H2O)3and H+(H2O)4, based on a mobility dispersion curve for nitrogen, is compared with experimental data. Positive ion density data are presented for four rocket flights during a PCA and one flight during an auroral absorption event. Finally, positive ion loss rates are shown based on the positive ion measurements and proton flux data obtained from rockets a

ISSN:0048-6604    

DOI:10.1029/RS009i006p00575

年代:1974

数据来源: WILEY

摘要:

We consider a wedge geometry for a model of a nonuniform layered earth. The plane wave spectrum of a line source excitation is allowed to reflect successively at the nonparallel interfaces. The semiconvergent series is truncated when the lowermost image term has been accounted for. The partial sum, so obtained, is considered to give a useful approximation to the resultant fields. It is found that there is a significant dependence on the tilt angle of the subsurface interface.

ISSN:0048-6604    

DOI:10.1029/RS009i006p00593

年代:1974

数据来源: WILEY

摘要:

Recent development in the optical scintillation theory has been adapted to the ionospheric geometry in order to study the ionospheric scintillation phenomenon in the presence of multiple scattering. Under approximations well satisfied in typical ionospheres for a frequency above about 20 MHz, the first through fourth moment equations have been derived and some analytic solutions given. The fourth moment equation has also been solved numerically. The numerical results show clearly the occurrence of focussing and saturation phenomena. In this paper the new multiple‐scatter effects are emphasize

ISSN:0048-6604    

DOI:10.1029/RS009i006p00599

年代:1974

数据来源: WILEY

摘要:

A systematic, thick refraction medium approach to calculating ionospheric radar refractive effects by means of propagation‐related integrals yields equations valid to second order in the tangent of the propagation angle with respect to the straight line between source and target. Significant differences are found from more intuitive developments currently used. When more than one propagation path exists between source and target, alternate propagation paths cannot be located reliably by the propagation integral method. However, inclusion of the higher‐order terms responsible for the alternate solutions does significantly improve the accuracy of the primary path solution when those terms can be estimated accurately in a strong refraction situat

ISSN:0048-6604    

DOI:10.1029/RS009i006p00609

年代:1974

数据来源: WILEY

摘要:

A previously reported method of application of ionospheric predictions to HF propagation in three dimensions is employed for an investigation of the monthly mean predicted behavior of the azimuthal angle of arrival of HF signals during the sunrise period for a medium range, midlatitude path oriented 27° east from north. A comparison of the prediction model results with experimental data collected over a five‐day period each month for twelve months shows that the use of the prediction model offers a significant overall improvement in reducing the errors due to the azimuthal angle‐of‐arrival deviations from the great circle azimuth. The factors contributing to the discrepancies between the prediction model results and experimental observations are ex

ISSN:0048-6604    

DOI:10.1029/RS009i006p00617

年代:1974

数据来源: WILEY

摘要:

The waveforms radiated by linear antennas loaded nonuniformly and continuously with resistance are investigated analytically. The antennas considered are symmetrical and excited at the centers by slice generators having a Gaussian pulse type of time dependence. Closed form expressions are developed for the far‐field waveforms produced by such antennas in any direction. The analytical results are compared with those obtained by direct numerical mean

ISSN:0048-6604    

DOI:10.1029/RS009i006p00621

年代:1974

数据来源: WILEY

摘要:

The time dependence is calculated of the radiated field from a resistively loaded, tubular antenna excited by a step‐function voltage across a circumferential delta gap. The resistive loading along the antenna is taken to be uniform and independent of frequency. Analytical expressions for the early‐time and late‐time behavior of the far field are derived. For intermediate time intervals the field is evaluated numerically. It is found that the late‐time behavior of the radiation field is inversely proportional to time squared, whereas in the case of zero resistance it varies in inverse proportion to the logarithm

ISSN:0048-6604    

DOI:10.1029/RS009i006p00631

年代:1974

数据来源: WILEY

ISSN:0048-6604    

DOI:10.1029/RS009i006p00639

年代:1974

数据来源: WILEY