排序方式： 共有70条查询结果，搜索用时 15 毫秒
61.
云南水汞的远震和近震前兆异常特征分析 总被引：2，自引：1，他引：1
本通过对云南西部７个水汞观测站,１９９０年￣１９９６年９月省内及邻区２６次Ｍ≥５．０级地震的水汞资料进行异常时空强及其形态的分析研究,总结出云南水汞在远震和近震前的前兆异常特征,用这些前兆异常特征对１９９６年９月后１年内各观测站的水汞异常与所发生的地震进行检验,结果很好。此项研究,有助于对未来发震区的判定。 相似文献
62.
On May 4, 1998, at 0227 UT an interplanetary shock crossed the WIND spacecraft, and half an hour later a Sudden Commencement occurred. Coinciding with the Sudden Commencement a rapid intensification of the flux of particle precipitation into the ionosphere was observed. Evidence is presented that the ionospheric electric fields were influenced by the associated dynamic variations of the ionospheric conductivities. Following the initial phase the ionospheric flow speeds increased rapidly over the next 20 min to more than 2000 m/s, in agreement with an increased effective coupling of the solar wind energy to the magnetosphere following the interplanetary shock that caused the Sudden Commencement. These strong flows were meandering in latitude, a type of plasma flow modulation that has been reported before to occur during Omega band events: a string of alternating field-aligned currents propagating eastward. The riometer absorption was found to be at a minimum in regions associated with outward directed field aligned currents. The riometer absorption regions (the regions of particle precipitation) were drifting with E × B drift speed of the ionospheric electrons. 相似文献
63.
对中国大陆５．０级以上强震的后续地震进行了分析,按成因将其划分为剩余型、诱导型和后生型３类。讨论了３种后续地震的主要特征及其在大震震源机理研究和地震预报中的意义。 相似文献
64.
显著地震地方平太阴时分布及其在伽师地震短临预报中的应用 总被引：7，自引：3，他引：4
研究了 1 3次 7级地震和 49次 6级地震震前震源区及其附近发生的二个显著地震地方平太阴时τ的分布规律。研究结果表明 ,在 62次 6、7级地震中 ,有 47次地震 ,其显著地震地方平太阴时的夹角≤ 45°,且 47次地震中有 68%的地震 ,其第二个显著地震发生以后 ,主震在未来2、3个月之内发生。因此这一现象可能是一种短期和临震前兆。作者用裂隙串通地震孕育模式即 IPE模式对这一现象作了解释 ,并把这一研究结果初步应用于地震预报实践中 ,较好地预报了新疆伽师地区 1 997年 4月 6日 6.3、6.4级 ,4月 1 1日 6.6级和 4月 1 6日 6.3级地震。 相似文献
65.
A useful index for estimating the transit speeds was derived by analyzing interplanetary shock observations. This index is the ratio of the in situ local shock speed and the transit speed; it is 0.6–0.9 for most observed shocks. The local shock speed and the transit speed calculated for the results of the magnetohydrodynamic simulation show good agreement with the observations. The relation expressed by the index is well explained by a simplified propagation model assuming a blast wave. For several shocks the ratio is approximately 1.2, implying that these shocks accelerated during propagation in slow-speed solar wind. This ratio is similar to that for the background solar wind acceleration. 相似文献
66.
E. Keppler 《Annales Geophysicae》1998,16(12):1552-1556
The variation of the peak intensity of energetic ions accelerated at CIR related shocks in the interplanetary medium as observed by instruments on board of ULYSSES during its pass towards the south polar region and from the north polar region back to its aphelium is discussed. From ULYSSES measurements alone it cannot be decided whether the observed variation is a function of latitude or of radial distance, as its orbit changes distance and latitude at the same time. Therefore ULYSSES data is compared with earlier observations by the PIONEER and VOYAGER spacecraft and concluded that the major part of the observed variation of the peak intensity seems to be due to a radial distance change, on to which, however, at higher latitudes a latitude dependent feature is superimposed. 相似文献
67.
C. Courtois R. A. D. Grundy A. D. Ash D. M. Chambers R. O. Dendy K. G. Mcclements N. C. Woolsey 《Astrophysics and Space Science》2005,298(1-2):93-98
Results from a scaled, collision-free, laser-plasma experiment designed to address aspects of collisionless plasma interaction
in a high-plasma β supernova remnant (SNR) are discussed. Ideal magneto-hydrodynamic scaling indicates that the experimental
plasma matches the SNR plasma at 500 ps. Experimental data show that the magnetic field can alter the plasma density profile
when two similar plasmas interact in a colliding geometry. These results are not explained by magnetic-field pressure; they
do, however, suggest magnetic field penetration that localizes the plasma particles to the Larmor radius, which appears smaller
than the size of the experiment and the particle mean-free paths and may thus increase the effective collisionality of the interacting plasma system. 相似文献
68.
We report submillimeter CO(6-5) observations around 15 nearby young stellar objects of low mass. The correlation between linewidth and peak temperature indicates shock heating of dense gas, presumably at the origin of molecular outflows. 相似文献
69.
Sandip K. Chakrabarti 《Journal of Astrophysics and Astronomy》1988,9(4):185-192
We study the effects of the presence of vortex rings surrounding a supersonic radio jet inside the cocoon of a radio lobe.
We show that both the jet and the shocked ambient medium are pinched. Flow speed inside the cocoon is always close to the
sonic value and it stays so by successively passing through several oblique shocks. We also discuss the possibility of the
non-linear growth of the instabilities of the contact surface to explain the numerical results in the literature. 相似文献
70.