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361.
Chian A.C.-L. Borotto F.A. Rempel E.L. Macau E.E.N. Rosa R.R. Christiansen F. 《Space Science Reviews》2003,107(1-2):447-461
Space plasmas are dominated by waves, instabilities and turbulence. Dynamical systems approach offers powerful mathematical
and computational techniques to probe the origin and nature of space environment turbulence. Using the nonlinear dynamics
tools such as the bifurcation diagram and Poincaré maps, we study the transition from order to chaos, from weak to strong
chaos, and the destruction of a chaotic attractor. The characterization of the complex system dynamics of the space environment,
such as the Alfvén turbulence, can improve the capability of monitoring Sun-Earth connections and prediction of space weather.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
362.
363.
给出用于毫米波频段精确测量介质片复介电常数的准光开放腔系统的误差分析,说明了近似理论引起的误差和被测量提取不准引起的误差。推导了相关的公式,给出了分析的数值结果和测量结果。 相似文献
364.
V.V. Hegai A.D. Legen’ka V.P. Kim K. Georgieva 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
A study of the critical frequency foF2 variations after the large earthquake (Ms = 8.1) which occurred on 29 September, 2009 in the region of Samoa Islands in the Pacific Ocean is carried out using data of the ionospheric station of Kwajalein. The epicenter of the earthquake was located at about 184 km southwest from Apia (the capital of West Samoa). It was found that wave-like perturbations of foF2 were observed for ∼3 h above the station (located approximately 3560 km northwest from the epicenter). The amplitude of the disturbance was as large as ∼20% of the average magnetic quiet day foF2 values. A comparison of the observed perturbations of foF2 with the ones detected at Stanford ionospheric station after the Alaska earthquake of 28 March 1964 (Ms = 8.4) showed a close similarity of the wave-like perturbations of foF2 in both cases. 相似文献
365.
M.V. Klimenko V.V. Klimenko I.E. Zakharenkova S.A. Pulinets B. Zhao M.N. Tsidilina 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The problems of physical explanation and possible mechanisms of the seismo-ionospheric effects formation are under discussion now. There are proposed different mechanisms of such effects, for example, large- and small-scale internal gravity waves (IGWs), atmospheric electric field, electromagnetic fields and emissions. However, the appearance of local large-scale seismo-ionospheric anomalies in Total Electron Content (TEC) is possible to explain only by two mechanisms: an atmospheric electric field and/or small-scale IGWs. In this paper, the simulation results for reproduction of the observed seismo-ionospheric great positive effects in TEC prior to strong Wenchuan earthquake are presented. The obtained results confirm the proposed mechanism of seismo-ionospheric effects formation by the penetration of the seismogenic electric field from the atmosphere into the ionosphere. It is suggested that so great TEC enhancement observed 3 days prior to Wenchuan earthquake could be explained by combined action of seismogenic vertical electric field and IGWs generated by the solar terminator. 相似文献
366.
Distributions with excess numbers of superthermal particles are common in space environments. They are well modelled by the
isotropic kappa distribution, or, where magnetic effects are important, the kappa-Maxwellian. This paper presents a review
of some studies of electrostatic and electromagnetic waves in such plasmas, based on the associated generalized plasma dispersion
functions, Z
κ and Z
κM. In particular, the effects of low values of κ are considered, i.e. strongly accelerated distribution functions. Recently the full susceptibility tensor for oblique propagation of electromagnetic
waves in a kappa-Maxwellian magnetoplasma has been established and has been applied to the study of whistler waves. 相似文献
367.
Leon Ofman 《Space Science Reviews》2005,120(1-2):67-94
Coronal holes have been identified as source regions of the fast solar wind, and MHD wave activity has been detected in coronal
holes by remote sensing, and in situ in fast solar wind streams. I review some of the most suggestive wave observations, and
discuss the theoretical aspects of MHD wave heating and solar wind acceleration in coronal holes. I review the results of
single fluid 2.5D MHD, as well as multi-fluid 2.5D MHD models of waves in coronal holes, the heating, and the acceleration
of the solar wind be these waves. 相似文献
368.
脉冲波形占空比的数字化测量及不确定度分析 总被引:2,自引:1,他引:2
介绍了脉冲波形占空比的3种数字化测量方法,它们分别是直接脉宽测量法、幅值统计测量法和平均值测量法。讨论了主要的不确定度来源,包括众数判别区间的影响、波形测量系统幅度测量误差的影响等等,给出了不确定度分析与评价过程.并结合一个实例,给出了脉冲波形占空比的不确定度评价结果。 相似文献
369.
根据相似理论放大的模型,实验研究了带有出流孔内流通道带孔—侧壁面的对流换热特性。实验采用加热钢带法,主要在主流雷诺数为2.5×104~10×104,出流比为1.0~4.0的范围内,测量了出流孔附近的换热系数分布,重点分析了主流雷诺数和出流比对壁面对流换热的影响规律。实验结果显示出流作用使出流孔下游区域内的换热得到强化。主流雷诺数一定时,随出流比的提高此区域换热强度提高,影响范围也扩大;出流比一定时,不同主流雷诺数下,带出流孔壁面换热强度与不带出流孔壁面换热强度的比值(Nu/Nu0)基本一致,换热被强化的程度无显著变化。 相似文献
370.
电火箭空心阴极发射体寿命研究 总被引:2,自引:0,他引:2
分析了影响电火箭空心阴极发射体寿命的各种因素。论述了空心阴极放电时,其内部化学反应生成物的迁移、扩散、蒸发和溅射。讨论了发射体发射材料的损耗速率与温度的关系,指出知度降低发射体的工作温度是延长空心阴极寿命的有效措施,还讨论了工质气体纯度和真空环境对发射体寿命的影响。 相似文献