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61.
E.L. Afraimovich I.K. Edemskiy S.V. Voeykov Yu.V. Yasyukevich I.V. Zhivetiev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009,44(7):824-835
Using long-term (1998--2009) total electron content (TEC) measurements from the GPS global network including dense network of GPS sites in USA and Japan, we have obtained the first data regarding the spatio-temporal structure and the statistics of medium-scale traveling wave packets (MS TWPs) excited by the solar terminator (ST). Total amount of the detected TWPs exceeds 565,000. There is no correlation between TWPs occurrence and geomagnetic and solar activity. We found that the diurnal, seasonal and spectral MS TWPs characteristics are specified by the solar terminator (ST) dynamics. MS TWPs are the chains of narrow-band TEC oscillations with single packet’s duration of about 1–2 h and oscillation periods of 10–20 min. The total duration of chain is about 4–6 h. The MS TWPs spatial structure is characterized by a high degree of anisotropy and coherence at the distance of more than 10 wavelengths. Occurrence rate of daytime MS TWPs is high in winter and during equinoxes. Occurrence rate of nighttime MS TWPs has its peak in summer. These features are consistent with previous MS travelling ionosphere disturbance (TID) statistics obtained from 630-nm airglow imaging observations in Japan. In winter, MS TWPs in the northern hemisphere are observed 3–4 h after the morning ST passage. In summer, MS TWPs are detected 1.5–2 h before the evening ST appearance at the point of observations, but at the moment of the evening ST passage in the magneto-conjugate point. The obtained results are the first experimental evidence for the hypothesis of the ST-generated ion sound waves. 相似文献
62.
Holger Winkler Justus Notholt 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
An ion chemistry model is used to investigate the negative chlorine ion chemistry of the mesosphere for quiet ionospheric conditions. Model results are presented for high latitudes in February as well as for the equator in Summer. For nighttime, Cl-, Cl-(HCl), and NO3−(HCl) are the most abundant chlorine anions in the mesosphere. The concentration of ClO3− depends significantly on its stability against collision-induced dissociation. In contrast to previous model predictions, the abundance of Cl-(H2O) is small. For daytime, photoelectron detachment and photodissociation have pronounced impact on the negative chlorine ion chemistry in the mesosphere. The abundance of all anion cluster is considerably smaller than at night. While Cl- decreases in the upper mesosphere, its abundance increases at lower altitudes. 相似文献
63.
Werner Däppen 《Space Science Reviews》1998,85(1-2):49-60
The equation of state is one of the three fundamental ingredients used to construct stellar models. The plasma of the interiors
of stars such as the Sun is only slightly non-ideal. However, the extraordinary accuracy of the helioseismological data requires
refined equations of state. It turned out to be necessary to include a Coulomb correction, commonly evaluated in the Debye-Hückel
approximation. Higher-order non-ideal effects have implications as well, both for plasma physics and for solar physics. As
a typical example, the recently studied thermodynamic consequence of excited states in compound particles is discussed. This
effect is of considerable relevance in the helioseismic determination of the helium abundance in the solar convection zone.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
64.
Douglas Gough 《Space Science Reviews》1998,85(1-2):141-158
Standard solar models, although they are free from the influence of much of the fluid motion that is bound to be present in
the Sun, have been shown by helioseismology to represent the spherically averaged structure of the Sun amazingly well. This
state of affairs has come about after painstaking refinements by a great many people of the pertinent microphysics, including
that which controls the equation of state, the opacity, the nuclear reaction rates and the diffusion that inhibits gravitational
segregation of chemical elements. It has instilled confidence in the modellers in being able to predict the composition of
the solar interior. But there are consequences of the flow, related particularly to redistribution of chemical species, that
can be difficult to identify observationally, yet which may degrade any inferences we might make. Their potential presence
must at least be acknowledged by anyone who tries to asses the reliability of the models. This report summarizes the discussions
in the preceding pages of this volume of the current theoretical and observational status of the subject, pointing to many
of the caveats that have been raised, and attempting at the same time to put them into a seemingly coherent discourse in the
context of our present understanding of the workings of the solar interior.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
65.
研究了在紫铜基材上用离子束增强沉积法(IBED)沉积TiB2薄膜后,在600,700和800℃的空气中氧化的动力学曲线;在INH2SO4溶液中,用动电位扫描法测定了其极化曲线和极化阻力,用SEM观察了其形貌,用俄歇电子谱仪(AES)分析了膜的成份,用X-射线衍射仪(XRD)研究了膜的微观结构;讨论了TiB2薄膜具有优良耐蚀性的机理。 相似文献
66.
Biswajit Sahu Debasish Roy 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2018,61(6):1425-1434
The dynamics of linear and nonlinear electrostatic shock excitations is studied in homogeneous, unmagnetized, unbounded and dissipative quantum plasma consisting of electrons and ions. The dissipation in the system is taken into account by incorporating the ion kinematic viscosity. The system is modelled using the quantum hydrodynamic equations in which the electrons are significantly affected by the quantum forces, viz., the quantum statistical pressure, the quantum Bohm potential and electron exchange-correlations due to electron spin. In the weakly nonlinear limit, using reductive perturbation method deformed Korteweg-de Vries Burgers’s (KdVB) equation, which elegantly combines the effects of nonlinearity, dispersion and dissipation is derived. It is found that the present model predicts the existence of both nonlinear oscillatory and monotonic shock structures. The temporal evolution, stability and phase-space dynamics of nonlinear ion acoustic shocks are investigated numerically to elucidate the effects of quantum diffraction, electron exchange correlation and ion kinematic viscosity. 相似文献
67.
目前针对国内薄膜瞬态热流传感器一致性较差、制备工艺不成熟等问题,提出了一种基于光刻工艺和离子束溅射镀膜工艺的制备方法,200对T型金属薄膜热电偶沉积在10mm×10mm的水冷块上,测量1μm的氧化铝热阻层温差,从而得到瞬态热流密度值。对新型高温瞬态热流密度传感器进行比对法标定,一致性误差为0.211%,即工艺的一致性约为99.79%。实验表明,研制的新型高温瞬态热流密度传感器的一致性好,制备工艺具备良好重复性和可移植性,能够满足高温瞬态热流检测需要,为热流传感器的推广应用及标准化、批量化生产提供了良好的技术支撑。 相似文献
68.
69.
为了发展基于电推进的大功率空间运输系统,需要开发和验证功率达数十千瓦的电推进系统,深空任务电推进系统优化的比冲要求高达105s。凯尔迪什研究中心(KeRC)正在开发这样的电推进部件。本文概述了 35kW离子推力器 IT-500及其流动单元FCU-500的验证现状。作为其验证的一部分,完成了IT-500 和 FCU-500的2000h寿命试验。其中,离子推力器大部分验证条件是:输入功率17.8kW,使用了40kg氙,2018h寿命试验。本文介绍了磁场和离子光学以及石墨格栅开发现状。 相似文献
70.
本文研究了磁尾等离子体片边界层宽频带静电噪声的产生机制.模型等离子体由暖的背景电子、暖的向地球方向的离子束流和较冷的向尾方向的离子束流组成.结果表明,静电离子束流-密度漂移不稳定性可以在比较宽的频率范围内激发,在低频区大传播角方向上增长率最大,在高频区小传播角方向上增长率也比较大。最大增长率的方向取决于离子束流和密度漂移的速度比值.这些结果与磁尾观测到的宽频带静电噪声特征符合一致. 相似文献