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821.
Xiang Wang Chen Zhou 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2018,61(9):2252-2258
Incoherent scatter radar (ISR) is the most powerful ground-based measurement facility to study the ionosphere. The plasma lines are not routinely detected by the incoherent scatter radar due to the low intensity, which falls below the measured spectral noise level of the incoherent scatter radar. The plasma lines are occasionally enhanced by suprathermal electrons through the Landau damping process and detectable to the incoherent scatter radar. In this study, by using the European Incoherent Scatter Association (EISCAT) UHF incoherent scatter radar, the experiment observation presents that the enhanced plasma lines were observed. These plasma lines were considered as manifest of the suprathermal electrons generated by the high-frequency heating wave during the ionospheric modification. The electron density profile is also obtained from the enhanced plasma lines. This study can be a promising technique for obtaining the accurate electron density during ionospheric modification experiment. 相似文献
822.
Barnard T.W. Wasserman J. Schroeder J.B. 《IEEE transactions on aerospace and electronic systems》1972,(2):156-160
A system concept for remote measurement of vehicle orientation with only passive devices mounted on a vehicle is presented. Three channels of polarization-modulated light are used to determine all three degrees of freedom of vehicle orientation. Two important system components are described, a polarization rotator and a retroreflector which leaves the polarization state invariant. Also, the method of data reduction is outlined and the system accuracy is discussed. 相似文献
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827.
A theoretical analysis of the sequential lobing technique for target angle tracking is presented. The signal power received by each antenna beam is assumed to pass through a logarithmic amplifier. A rigorous statistical approach is adopted in the analysis for both non-fluctuating and fluctuating targets. Closed form expressions are derived for the normalized mean error and rms error of the angle estimate for Swerling 0, I, II, and III targets. Results are compared with those obtained using a simplified approach for the non-fluctuating target 相似文献
828.
W. H. Matthaeus G. P. Zank R. J. Leamon C. W. Smith D. J. Mullan S. Oughton 《Space Science Reviews》1999,87(1-2):269-275
Mechanisms for the deposition of heat in the lower coronal plasma are discussed, emphasizing recent attempts to reconcile
the fluid and kinetic perspectives. Structures at the MHD scales are believed to act as reservoirs for fluctuation energy,
which in turn drive a nonlinear cascade process. Kinetic processes act at smaller spatial scales and more rapid time scales.
Cascade-driven processes are contrasted with direct cyclotron absorption, and this distinction is echoed in the contrast between
frequency and wavenumber spectra of the fluctuations. Observational constraints are also discussed, along with estimates of
the relative efficiency of cascade and cyclotron processes.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
829.
对氏地球轨道环境对航天器表面材料的影响和航天器表面材料的低地球轨道环境寿命评定方法进行了介绍;并对低地球轨道环境和地面试验环境下,有无保护涂层的业胺所受冲蚀作用进行了成功的数值模拟,获得了具有工程应用价值的数值计算结果。该工作对航天器的设计具有指导意义。 相似文献