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本文扼要介绍了PMOE行星历表研究当前的进展和工作 ,给出了PMOE2 0 0 2与DE40 5历表的比较。 相似文献
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A relativistic delay model for Earth-based very long baseline interferometry (VLBI) observation of sources at finite distances is derived. The model directly provides the VLBI delay in the scale of terrestrial time. The effect of the curved wave front is represented by using a pseudo source vector K = (R
1 + R
2)/(R
1 + R
2), and the variation of the baseline vector due to the difference of arrival time is taken into account up to the second-order by using Halley’s method. The precision of the new VLBI delay model is 1 ps for all radio sources above 100 km altitude from the Earth’s surface in Earth-based VLBI observation. Simple correction terms (parallax effect) are obtained, which can also adopt the consensus model (e.g. International Earth Rotation and Reference Frames Service conventions) to finite-distance radio source at R > 10 pc with the same precision. The new model may enable estimation of distance to the radio source directly with VLBI delay data. 相似文献
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中国大陆地震活跃期和全球部分地震带强震活动的相关性研究 总被引：4，自引：0，他引：4
对全球部分地震带强震活动的研究表明，中国大陆地震活跃期与全球某些地震带强震活动呈一定程度的正相关或负相关，且有些地震带的强度震超前于中国大陆活动或平静，因此，可以利用相关地震带的强震活动和某些地震带的超前性，预测中国大陆的地震活动趋势及判定中国大陆的地震活跃期。 相似文献
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Using the new generation Earth’s gravity field models EIGEN-2S, GGM01S and EIGEN-GRACE02S generated by the space missions CHAMP and GRACE, we have obtained an accurate measurement of the Lense–Thirring effect with the LAGEOS and LAGEOS II satellites analyzing about 10 years of data with the EIGEN-2S and GGM01S models and about 11 years of data with EIGEN-GRACE02S. This new analysis is in agreement with our previous measurements of the Lense–Thirring effect using the LAGEOS satellites and obtained with the JGM-3 and EGM96 Earth’s models. However, the new determinations are more accurate and, especially, more robust than our previous measurements. In the present analysis we are only using the nodal rates of the two satellites, making no use of the perigee rate, as in our previous analyses. The perigee is affected by a number of non-gravitational perturbations difficult to be modelled and whose impact in the total error budget is not easy to assess. Using the EIGEN-2S model, we obtain a total error budget between 18% and 36% of the Lense–Thirring effect due to all the error sources. Specifically, by using EIGEN-2S, we obtain: μ = 0.85, with a total error between ±0.18 and ±0.36, with GGM01S we get μ = 1.06 with a total error between ±0.19 and ±0.24 and with EIGEN-GRACE02S we obtain μ = 0.99, with a total error between ±0.05 and ±0.1, i.e., between 5% and 10% of the general relativistic predicted value of the Lense–Thirring effect. In addition to the analyses using EIGEN-2S, GGM01S and EIGEN-GRACE02S without the use of the perigee, we have also performed an analysis using the older model EGM96 with our previous method of combining the nodes of the LAGEOS satellites with the perigee of LAGEOS II. However, this analysis was performed over a period of about 10 years, i.e. about 2.5 times longer than any our previous analysis. The result using EGM96 over this longer period of observation agrees with our previous results over much shorter periods and with the EIGEN-2S, GGM01S and EIGEN-GRACE02S measurements of μ. In addition to the accurate determination of frame-dragging and in agreement with our previous analyses of the orbits of the LAGEOS satellites, we have observed, since 1998, an anomalous change in the Earth quadrupole coefficient, J2 which agrees with recent findings of other authors. This anomalous variation of J2 is accurately observed both on the node of LAGEOS and LAGEOS II and it is independent of the model used, i.e., it is observed by using the model EGM96 or by using EIGEN-2S, GGM01S or EIGEN-GRACE02S. However, this anomalous variation of the Earth quadrupole coefficient does not affect at all our determination of the Lense–Thirring effect thanks to the total elimination of the J2-induced errors with our especially devised estimation technique. 相似文献
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Particle acceleration via Poynting vector with toroidal magnetic field is studied in 3D PIC simulation of electron-positron
plasma. We choose two different initial magnetic field configurations to compare how the particle acceleration is affected
by the expansion of electromagnetic wave. In the cylindrical case, the electromagnetic field strength decays as (ct)−2, and particles are accelerated in the radial direction as well as the axial direction. Rayleigh-Taylor instability is also
observed at the center of the cylinder. In the torus case, the field strength decays as (ct)−3, making the acceleration less efficient. Particles accelerated in the axial direction by E × B force creates strong charge separation. 相似文献
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Manuel Ortega-rodríguez Alexander S. Silbergleit Robert V. Wagoner 《地球物理与天体物理流体动力学》2013,107(1):75-115
This article studies the hydrodynamical problem of normal modes of small adiabatic oscillations of relativistic barotropic thin accretion disks around black holes (and compact weakly magnetic neutron stars). Employing Wentzel-Kramers-Brillouin (WKB) techniques, we obtain the eigenfrequencies and eigenfunctions of the modes for different values of the mass and angular momentum of the central black hole. We discuss the properties of the various types of modes and show for the first time that modes covering the whole extension of the disk (full-disk p-modes) can exist within the studied thin disk model. However, these modes have relatively short wavelengths. 相似文献
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以太阳系质心参考系为基础，根据太阳系的质心参考系和非旋转地球质心参考系的坐标转换关系，推导了太阳系天体地面VLBI观测的相对论时间延迟模型，给出了一个通用的解析表达式．根据这一公式可以得到平劲松博士所采用的公式，以及当地心与源的距离无限大时，可得河外射电源VLBI观测的Zhu—Groten模型、Shapiro模型和IERS(92，96)推荐模型．所推导的公式严格解析且无误差，在实际应用中建议采用这一公式．同时详细地讨论了所推导公式的实用范围和各种舍掉项的量级估计，并详细给出了时间延迟理论模型的计算步骤． 相似文献