Reconstructed 3-d magnetic field structure and hard X-ray two ribbons for 2000 Bastille-day event

The Bastille-day event in 2000 produced energetic 3B/X5.6 flare with a halo CME, which had great geo-effects consequently. This event has been studied extensively and it is considered that it follows the two-ribbon flare model. The flare/CME event was triggered by an erupting filament and TRACE observations showed formation of giant arcade structures during the flare process. Hard X-ray (HXR) two ribbons revealed for the first time in this flare event (Masuda et al., 2001). The reconstruction of 3-D coronal magnetic fields revealed a magnetic flux rope structure, for the first time, from extrapolation of observed photospheric vector magnetogram data and the flux rope structure was co-spatial with portion of the filament and a UV bright lane (Yan et al., 2001a, 2001b). Here we review some recent work related to the flux rope structure and the HXR two ribbons by comparing their locations and the flux temporal profiles during the flare process so as to understand the energy release and particle accelerations. It is proposed that the rope instability may have triggered the flare event, and reconnection may occur during this process. The drifting pulsation structure in the decimetric frequency range is considered to manifest the rope ejection, or the initial phase of the coronal mass ejection. The HXR two ribbons were distributed along the flux rope and the rope foot points coincide with HXR sources. The energy dissipation from IPS observations occurred within about 100 R _⋅ is consistent with the estimate for the flux rope system. This revised version was published online in August 2006 with corrections to the Cover Date.     

Relationship between daily variation of cosmogenic nuclide Be-7 concentration in atmosphere and solar activities

Daily Be-7 concentrations in air at the height of 15 m are continuously observed at 38°15.2′N, 140°20.9′E, between 2000 and 2001. The average concentration and the relative standard deviation were 4.0 mBq/m³ and 50% in 2000–2001, respectively. The Be-7 concentrations increased 2.5% with the decrease in the sunspot numbers by 6.7% for the term of two years. From the power spectral analysis, the periodicity of 26 days is shown for the daily Be-7 concentrations. The folding analysis indicates that the time variation of the Be-7 concentration is similar to that of the ground-based neutron counting rate, and the phase delay for the minimum portion of Be-7 concentration was roughly 8 days to the maximum sunspot number. These results indicate that the Be-7 concentrations in the air at ground level have 26 day periodicity as a component of time variations and the time variation is caused by the solar modulation of galactic cosmic rays, which corresponds to the variation of the sunspot number due to the rotation of the sun.     

空间实验室大面积太阳电池阵技术研究

介绍了空间实验室大面积太阳电池阵的方案构型，并进行了模态分析、热结构耦合分析和动力学仿真分析。生产出了全尺寸的集成演示样机，进行了展开试验、主展开机构的模态试验，以及半刚性太阳电池板和二自由度驱动机构的振动试验。计算和试验结果表明，技术方案是可行的。     

周期结构和太阳电池翼的模态分析

基于周期结构的振动理论,把折叠状态太阳电池翼当作拟周期结构处理,解释了太阳电池翼在进行模态分析时所出现的“主模态局部化”现象,了解该现象对于在实验模态分析中确定阻尼系数具有重要意义。同时从理论上说明了,简单的基板模型的第1阶特征值是整翼模型的第1阶特征值的近似值。两个算例计算的结果支持了这个观点。     

人工拉格朗日点附近的被动稳定飞行

利用太阳帆能在三体问题中实现人工拉格朗日点,人工拉格朗日点克服了经典拉格朗日点位置固定的缺点,研究人工拉格朗日点的被动控制对深空探测有重要的意义。理论上人工拉格朗日点都不稳定,研究表明在被动控制下存在某些人工拉格朗日点的稳定特性与稳定平衡点非常接近,在工程上可以认为稳定。被动控制可以通过设计太阳帆来实现,本文给出了被动稳定太阳帆的设计,在该设计下考虑轨道和姿态的耦合动力学方程。基于该耦合方程研究了人工拉格朗日点的稳定性。仿真结果表明被动太阳帆使得人工拉格朗日点稳定。     

地球同步卫星远地点变轨期间的三轴姿态稳定

本文提供了地球同步三轴稳定卫星在远地点变轨机动过程中的卫星动力学模型,其中考虑了刚体、液体晃动和帆板振动的耦合,这些模型经过实际工程验证,证明是正确的。本文还给出了控制器结构,它由PID和各种晃动滤波器及帆板挠性滤波器组成。工程设计证明,这种控制器结构可满足设计要求且简单可靠。本文还给出了系统稳定性分析结果及数字仿真结果。     

太阳帆板绳索联动同步机构的机理和功能分析

绳索联动机构（ＣＣＬ）是航天器上最常用的附件同步展开控制机构。本文将其等效为一个被动控制器，推导了机构的数学模型，分析了其参数对太阳电池阵同步展开的影响，并对一大型单翼太阳电池阵的展开过程进行了仿真，其结果和实验基本相符。同时得出了一些对工程设计有参考意义的结论。     

1989年3月大宇宙线暴事件的特征

本文分析了1989年3月一系列大耀斑等离子体抛射引起的宇宙线强度变化的特征.除对中子成分分析外,还对μ介子成分及其各向异性特征作了分析,讨论了宇宙线强度变化与太阳耀斑特性和地磁扰动之间的关系。分析发现,宇宙线的Forbush下降不仅与太阳耀斑的级别、持续时间,以及在日面上的位置有关,而且还与光学耀斑是否伴有强的X射线暴、是否有强的射电爆发,以及是否引起强的地磁暴紧密有关.各向异性分析表明,3月大事件的各向异性明显小于宁静时的各向异性,这可能是因为受到太阳活动强烈调制之后,宇宙线各向异性趋于减小的原因.     

Prompt effects of solar wind variations on the inner magnetosphere and midlatitude ionosphere

It is well known that the solar wind can significantly affect high-latitude ionospheric dynamics. However, the effects of the solar wind on the middle- and low-latitude ionosphere are much less studied. In this paper, we report observations that large perturbations in the middle- and low-latitude ionosphere are well correlated with solar wind variations. In one event, a significant (20–30%) decrease of the midlatitude ionospheric electron density over a large latitudinal range was related to a sudden drop in the solar wind pressure and a northward turning of the interplanetary magnetic field, and the density decrease became larger at lower latitudes. In another event, periodic perturbations in the dayside equatorial ionospheric E × B drift and electrojet were closely associated with variations in the interplanetary electric field. Since the solar wind is always changing with time, it can be a very important and common source of ionospheric perturbations at middle- and low-latitudes. The relationship between solar wind variations and significant ionospheric perturbations has important applications in space weather.     

"神舟二号"大气密度探测器的探测结果Ⅱ.在太阳和地磁扰动期间高层大气密度的变化

选用了Sz—2大气密度探测器在2001年2—4月间的探测数据,进行日照和阴影区域热层大气密度对太阳和地磁活动程度的响应变化的探讨．结果表明,日照区大气密度峰值主要随F10.7值而变,在地磁扰动期间,阴影区大气密度对扰动的响应更明显,通常响应变化开始于高纬度地区,然后向低纬度地区推移．