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A.L. Mishev J.N. Stamenov I.I. Angelov N.O. Ahababian I.N. Kirov E.S. Malamova 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
We review the main activities carried out at Moussala peak (2925 m above sea level, 42°11′N, 23°35′E) station in Bulgaria, connected with cosmic ray investigations during the last five decades. Several important results obtained at the station are reported. The detector design and corresponding methodological studies of the presently operational devices are shown as well, precisely the Cherenkov light telescope, lead free neutron monitor and muon telescope. The scientific potential of the existing complex is discussed. 相似文献
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用Morlet小波变换对Oulu台站和Apatity台站(主要是Apatity台站)1998-2002年间宇宙线静日和地磁暴前的地面宇宙线强度变化特征进行分析,得到:在宇宙线静日期间普遍存在准24h周期变化特征,并且在当地时间0200,1400左右分别出现最小值和最大值;对12个例子的分析可以看到地面宇宙线强度在地磁暴之前l-2天均出现了不同于宇宙线静日期间变化特征,或有小尺度周期出现,或周期变化完全消失,或有异常24h周期变化,这种变化特征在一定程度上可作为地磁预报的先兆特征之一。 相似文献
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采用2θ-ω对称扫描,对(111)、(333)、(044)不同衍射面进行了ω扫描,得到了InSb不同衍射面之间强度和半峰宽度的规律;对晶片上不同位置进行了同一衍射面的ω扫描,得到半峰宽度的mapping,此外,还对材料进行了倒易空间(RSM)扫描。测试结果表明InSb材料结晶质量完好,均匀性好,符合制造良好光电器件的标准。 相似文献
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本文针对一平面激波S绕过坡角为30°的山峰后与地面作用所产生的波系图案等问题,通过激波管光测模型实验手段进行了分析和研究。实验是在入射激波马赫数Μ_i=1.18,1.32,1.74,2.00和2.29等五种条件下进行的。实验结果表明,在入射激波S和反射激波R之间出现了一接触面C,并与Skews关于平面激波绕凸角壁面时所得到的结果做了比较。与此同时,从我们所拍摄的纹影流场照片上可以看出,平面激波S绕过30°山峰后与地面作用所产生的反射波均属于马赫反射的范围。 相似文献
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《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2020,65(4):1306-1320
High frequency ionosphere vertical sounding, as an important and representative application for detecting the ionosphere and studying the characteristics of radio propagation, can be utilized to monitor the ionosphere continuously variation and to acquire the ionosphere asymmetrical features of diverse scale above the ionosphere vertical sounding stations. This is a first article on real time application of numerical methods to obtain the parameters of traveling ionosphere disturbances (TIDs) using vertical incident ionograms. In this paper, the distribution of ionosphere electron density with TIDs is constructed using a background ionosphere model superimposed a perturbation theory model. The background ionosphere electron density is modelled by the inversion of vertical incident ionograms which are observed before the appearance of the disturbance. Based on the fourth order Adams-Bashforth-Moulton (the so-called ABM) predictor corrector method, instead of Runge-Kutta method, the fast digital ray tracing method is established. According to process of the disturbed trace simulation and parameters inversion, the characteristic parameters of ionosphere disturbance at different detection time can be obtained in real time. The numerical analysis of TIDs is then captured completely. 相似文献
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为了解决目标识别、隐身目标设计等研究领域对雷达图像需求日益增加的问题,提出了一种基于射线追踪的快速雷达图像仿真方法。该方法利用射线追踪计算每一个射线管的散射电场及其在雷达成像平面的投影坐标,通过将所有射线管的贡献在像域进行累加得到1幅二维雷达图像。通过对不同路径射线的聚类,可实现对散射贡献的分离,从而建立目标部件与强散射源的对应关系,并对复杂目标雷达图像进行解释。给出了Slicy目标的快速雷达图像仿真与算例分析,分析结果表明:基于射线追踪的快速雷达图像仿真方法可对复杂雷达图像进行有效预测,并能对强散射源进行成因分析。 相似文献
28.
M. Pietrella A. Pignalberi M. Pezzopane A. Pignatelli A. Azzarone R. Rizzi 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2018,61(10):2569-2584
Three-dimensional (3-D) electron density matrices, computed in the Mediterranean area by the IRI climatological model and IRIEup and ISP nowcasting models, during some intense and severe geomagnetic-ionospheric storms, were ingested by the ray tracing software tool IONORT, to synthesize quasi-vertical ionograms. IRIEup model was run in different operational modes: (1) assimilating validated autoscaled electron density profiles only from a limited area which, in our case, is the Mediterranean sector (IRIEup_re(V) mode); (2) assimilating electron density profiles from a larger region including several stations spread across Europe: (a) without taking care of validating the autoscaled data in the assimilation process (IRIEup(NV)); (b) validating carefully the autoscaled electron density profiles before their assimilation (IRIEup(V)).The comparative analysis was carried out comparing IRI, IRIEup_re(V), ISP, IRIEup(NV), and IRIEup(V) foF2 synthesized values, with corresponding foF2 measurements autoscaled by ARTIST, and then validated, at the truth sites of Roquetes (40.80°N, 0.50°E, Spain), San Vito (40.60°N, 17.80°E, Italy), Athens (38.00°N, 23.50°E, Greece), and Nicosia, (35.03°N, 33.16°E, Cyprus). The outcomes demonstrate that: (1) IRIEup_re(V), performs better than ISP in the western Mediterranean (around Roquetes); (2) ISP performs slightly better than IRIEup_re(V) in the central part of Mediterranean (around Athens and San Vito); (3) ISP performance is better than the IRIEup_re(V) one in the eastern Mediterranean (around Nicosia); (4) IRIEup(NV) performance is worse than the IRIEup(V) one; (5) in the central Mediterranean area, IRIEup(V) performance is better than the IRIEup_re(V) one, and it is practically the same for the western and eastern sectors.Concerning the overall performance, nowcasting models proved to be considerably more reliable than the climatological IRI model to represent the ionosphere behaviour during geomagnetic-ionospheric storm conditions; ISP and IRIEup(V) provided the best performance, but neither of them has clearly prevailed over the other one. 相似文献
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