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中低纬地区地磁脉动的研究 总被引：1，自引：0，他引：1
杨少峰 《地震地磁观测与研究》1992,13(1):50-57
近年来我们对中低纬地区地磁脉动进行了大量的观测和研究。本文不仅介绍了观测仪器的设计、台网设置及数据处理方法。而且还简要地介绍了一些主要科研成果,如低纬Pc3脉动特点,低纬Pi2脉动偏振特性。南极地区的地磁脉动观测结果,以及在磁暴和太阳耀斑期间在低纬地区观测的地磁脉动。这对于进一步认识中低纬地区地磁脉动是十分有益的。 相似文献
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本文分析了1988年12月和1989年1月在长春、北京、兰州3个台站上观测的地磁脉动资料,研究了3个台站同时记录到的Pi2地磁脉动的频谱特征和偏振特性,进而对低纬Pi2地磁脉动的产生和传播机制做了理论研究. 相似文献
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本文利用低纬地磁台站的Pi1、Pi2地磁脉动（Pi1-2）资料和地球同步轨道的Pc5地磁脉动资料,对2004年1月到2006年12月38个磁暴事件的地磁脉动参数进行了统计分析.在此基础上,考虑相对论电子的局部加速机制,并加入损失机制,建立了一个初步的磁暴期间地球同步轨道相对论电子通量对数值的预报模型.利用该模型,我们对上述38个磁暴事件进行预报试验,最优化结果是：相对论电子通量对数值的预测值和观测值之间的线性相关系数为0.82,预报效率为0.67.这说明该模式具有较好的预报效果,也表明利用地磁脉动参数进行相对论电子通量预报是可行的. 相似文献
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《地震地磁观测与研究》2016,(6)
通过将廊坊、富克地磁台站数据与国内地磁台站十三陵、三亚台以及国际标准地磁台站MMB台的观测数据对比分析,发现各地磁台站数据变化幅度相近、相关性高,对地磁暴有明显响应,且磁暴期间各时段扰动幅度相近。同时,以高质量地磁数据为基础,采用快速傅里叶变换,对廊坊与富克地磁台站的地磁观测数据开展地磁脉动提取,研究发现,两个台站在地磁暴期间均能观测到明显的Pi1、Pi2、Pc5地磁脉动,且Pc5的持续时间、平均强度、变化幅度和Pi1的持续时间、变化幅度及Pi2的变化幅度均有明显增加,为今后开展地磁脉动与高能电子增强事件相关性研究奠定了基础。 相似文献
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本文重点分析了在1989年3月13日发生的强急始型磁暴期间观测到的丰富的地磁脉动现象.文中列出各种地磁脉动发生的时间和波形曲线范例,并对各种地磁脉动做了傅里叶谱分析.这不仅可以帮助我们了解这些地磁脉动和磁暴的关系,而且能使我们进一步认识磁暴过程的能量传输实质. 相似文献
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1996年9月我们在河南信阳——汤阴布设了由６个测点组成的测线,对Pi2地磁脉动进行了同时观测,并对该南北测线上Pi2地磁脉动出现的同时性进行了探讨．分析结果指出,Pi2地磁脉动首先出现在测线最南端的信阳测点,越往北同一变化出现的时间越晚．该区域地表的南北向似传播速度约为140ｋｍ/s．基于Pi2地磁脉动随时间变化的不稳定性,以及基子波的可延伸性与局部化特性,我们选择合适的基子波形式,利用子波变换分析了Pi2脉动所含主要的周期变化成分的周期和振幅随时间的变化,指出其周期和振幅都随时间有复杂的变化形式． 相似文献
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1997年3月9日漠河日全食期间地磁脉动的主要特征 总被引：1，自引：0，他引：1
１９９７年３月９日漠河日全食期间分别在漠河地磁台,北京怀柔地磁脉动站和三亚地磁台开展了地磁脉动的观测。本文重点分析了３月９日０７：００ＬＴ至１１：００ＬＴ日全食前后漠河地区地磁脉动的观测资料,研究了日全食期间地磁脉动的主要特征,并对日全食期间地磁脉动的激发机制做了较深入的人。 相似文献
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IntroductionThere are many kinds of fluctuations in magnetosphere plasma, frequencies concerned are ofa broad range (10--3~106 Hi). Except for electro-magnetic waves (whistled, hydromagnetic wave Alven wave), there is static electric wave mode (plasma wave -- election acoustic wave, ionacoustic wave). Among them, a main fluctuation of hydromagnetic wave phenomena is geomagnetic pulsation. Dungey (1954) believed at first in 1954 that this kind of pulsations can be attributed to hydromagnetic w… 相似文献
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Pi2地磁脉动的理论进展 总被引：1，自引：1，他引：1
目前，国内外在Ｐｉ２脉动的理论研究上取得了很大进展，现在问题的焦点是如何完整地解释Ｐｉ２脉动的全球特征和激发机制。解释Ｐｉ２脉动的理论主要有三种，即瞬态响应机制，亚暴电流楔理论和磁层空腔振荡理论。本文介绍了这三种理论的由来和发展，分析了每种理论在Ｐｉ２脉动研究中的贡献，并对Ｐｉ２脉动理论研究的进一步发展提出一些看法。 相似文献
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The characteristics of substorm-associated Pi2 pulsations observed by the SABRE coherent radar system during three separate case studies are presented. The SABRE field of view is well positioned to observe the differences between the auroral zone pulsation signature and that observed at mid-latitudes. During the first case study the SABRE field of view is initially in the eastward electrojet, equatorward and to the west of the substorm-enhanced electrojet current. As the interval progresses, the western, upward field-aligned current of the substorm current wedge moves westward across the longitudes of the radar field of view. The westward motion of the wedge is apparent in the spatial and temporal signatures of the associated Pi2 pulsation spectra and polarisation sense. During the second case study, the complex field-aligned and ionospheric currents associated with the pulsation generation region move equatorward into the SABRE field of view and then poleward out of it again after the third pulsation in the series. The spectral content of the four pulsations during the interval indicate different auroral zone and mid-latitude signatures. The final case study is from a period of low magnetic activity when SABRE observes a Pi2 pulsation signature from regions equatorward of the enhanced substorm currents. There is an apparent mode change between the signature observed by SABRE in the ionosphere and that on the ground by magnetometers at latitudes slightly equatorward of the radar field of view. The observations are discussed in terms of published theories of the generation mechanisms for this type of pulsation. Different signatures are observed by SABRE depending on the level of magnetic activity and the position of the SABRE field of view relative to the pulsation generation region. A twin source model for Pi2 pulsation generation provides the clearest explanation of the signatures observed. 相似文献
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本文试图建立一个产生低纬Pi2 脉动的亚暴三维电流体系模型.用这个模型可以模拟地球表面不同纬度和经度上记录的Pi2脉动的波形和偏振图,与低纬Pi2脉动的多台观测结果基本相符.从而定量地解释了Pi2脉动和亚暴电流体系的关系. 相似文献
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An intensification of auroral luminosity referred to as an auroral break-up often accompanies the onset of geomagnetic pulsation (Pi 2) at the dip-equator. One such auroral break-up occurred at 2239 UT on 16 June, 1986, being accompanied by weak substorm activity (AE≈50 nT) which was recorded in all-sky image of Syowa Station, Antarctica (66.2°S, 71.8°E in geomagnetic coordinates). The associated Pi 2 magnetic pulsation was detected by a fluxgate magnetometer in the afternoon sector at the dip-equator (Huancayo, Peru; 1.44°N, 355.9° in geomagnetic coordinates; 12.1°S, 75.2°W in geographic coordinates; L = 1.00). In spite of the large separation of the two stations in longitude and latitude, the auroral break-up and subsequent luminosity modulation were seen to be correlated with the wave form of the ground Pi 2 pulsation. This occurred in such a way that the luminosity maximum was seen to occur at the phase of maximum amplitudes of Pi 2 wave form. We argue that the observed correlation could be interpreted as indicating a Pi 2-modulation of a field-aligned acceleration of the low energy electrons that may occur near the equator of the midnight magnetosphere. 相似文献
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P. R. Sutcliffe 《Annales Geophysicae》1997,15(10):1257-1264
The pattern recognition capabilities of artificial neural networks (ANNs) have for the first time been used to identify Pi2 pulsations in magnetometer data, which in turn serve as indicators of substorm onsets and intensifications. The pulsation spectrum was used as input to the ANN and the network was trained to give an output of +1 for Pi2 signatures and –1 for non-Pi2 signatures. In order to evaluate the degree of success of the neural-network procedure for identifying Pi2 pulsations, the ANN was used to scan a number of data sets and the results compared with visual identification of Pi2 signatures. The ANN performed extremely well with a success rate of approximately 90% for Pi2 identification and a timing accuracy generally within 1 min compared to visual identification. A number of potential applications of the neural-network Pi2 scanning procedure are discussed. 相似文献