极光光谱学发展史和现状

本文阐述了极光光谱学的发展历史和现状,并进一步说明极光绿线的解释对极光光谱学发展的贡献,以及激发过程的深入研究会出现的新问题.     

木卫一等离子体环中冷热离子的轨迹

通过模拟木卫一等离子体环中冷热离子的轨迹来分析离心力对冷热离子作用的大小,说明冷离子在离心力的约束下沿着磁力线来回反射,不可能进入木星大气层,而离心力对热离子运动的影响不大.木卫一等离子体环主要由高密度的冷等离子体组成,因此还需要一个能使冷离子离开木卫一等离子体环进入木星大气层的机制,使它能够引发木卫一尾迹极光的发射.     

极轨卫星在780km高度上测得的高能粒子辐射事件

对搭载于我国第一颗地球资源卫星上的“星内高能粒子探测器”首批资料进行初步分析表明，在卫星780km轨道高度上所纪录到的所有高能粒子通量事件都只出现在3个地理区域，即两半球的高纬极光带和南大西洋地磁异常区。低能档电子在这3个区域都有出现，而高能档电子和质子在太阳宁静条件下，一般只出现在南大西洋异常区。从统计结果还可看出，南极光带附近的粒子通量大于北半球极光带。而在北极光带，与南大西洋异常区大体相同的经度附近，高能粒子的通量事件有一个明显的空隙区域。另一个观测事实是，0．5—2．0MeV能档的电子通量在极光区远大于2．0MeV以上能档的电子通量，而在南大西洋地磁异常区，两个通道的电子通量差别不大。与现有理论模型和国外大致相同轨道上的空间高能辐射环境直接观测资料对比还表明，卫星舱内的辐射与舱外的空间辐射环境是完全相关的。积累的有关资料不但是航天设计和环境应用研究所需的重要参量之一。也是空间物理基础研究特别是辐射带研究的重要数据。     

Locating the polar cap boundary of postnoon sector from observations of 630.0 nm auroral emission at Zhongshan Station

We studied the ground observations of 630.0 nm auroral emission at Zhongshan Station to determine the polar cap boundary with the latitudinal profile of emission intensity. The open-closed field time boundary is assumed to lie at the boundary between polar rain and plasma sheet precipitation. We assume that nonprecipitation-dependent sources of 630.0 nm emission cause a spatially uniform luminosity in the polar cap and that auroral zone luminosity is also spatially uniform. Therefore we determine the location of the polar cap boundary of postnoon sector from the auroral emission data each time by finding the best fit of the observations to a step function in latitude and we produce a time series of the location of the polar cap boundary. The average error of the practice in the paper is less than 0.8 degree. Foundation item: Supported by the National Natural Science Foundation of China (No. 40044013) Biography: Liu Li-gang (1976-), male, Master candidate, research direction: auroral physics.     

Ground observations of post-noon aurora: a case study

The characteristics of the post-noon aurora observed at Antarctic Zhongshan station on June 12, 1999, were discussed and analyzed. In the condition of the magnetic activity is not large (K _p≈1), for post-noon 630.0 nm emissions, the total fluxes of soft precipitating particles were increasing from 10∶50 UT to 13∶35 UT and were decreasing from 13∶35 UT to 18∶00 UT in almost monotonous way. Away from noon, the 557.7 nm emissions increased gradually from 10∶50 UT to 17∶10 UT. The behaviors of the precipitating particles for exciting 630.0 nm aurora and 557.7 nm aurora were quite different. The peak intensity of 630.0 nm and 557.7 nm emissions appeared at about 13∶35 UT and 15∶40 UT respectively, the time difference of two peaks is about 2 h. The energy of precipitating electrons remained fairly steady until 15∶00 UT when it rose dramatically. Foundation item: Support by the National Natural Science Foundation of China (49634160) Biography: Ai Yong (1958-), male, Associate professor, research direction: upper atmosphere physics.     

Analysis of characteristic of aurora substorm observed at Antarctic Zhongshan station

The characteristics of a strong aurora substorm observed at Antarctic Zhongshan station (magnetic latitude=74.5°) on 8 April, 1999, were discussed and analyzed. The developing steps of the aurora substorm that happened in dusk time were almost the same with that of midnight aurora substorm. The averaged moving speed of the aurora arc toward pole area during the substorm expansion phase was about 3.0 km/s, westward-traveling surge speed was about 2.0 km/s. The extension from south to north in the substorm can cover 1100 km in distance. Foundation item: Supported by the National Natural Science Foundation of China (49634160) Biography: Ai Young (1958-), male, Associate professor, research direction: upper atmosphere physics.     

极光O_1s激发时变参数的计算

参数承时间而变化，表面总亮度由原子氧[OI]跃迁和N2＋第一负带B2eu -X2Eg 跃迁而发散的极光展现时，亮度测量提供了关于高层大气中O（1S）态激发机理的信息，用一种基于直接和间接激发相结合的四参数自回归外源（exogeneous)过程可以对观察数据建模，并使用时域递归的RIV算法来确定过程的牧师参数（两个激发率，两个弛豫时间），本文将这方法应用于实际极光亮度数据，由此确定的参数与使用非递归互谱方法所得的结果进行比较，显出了它的优越性，改进后的这种算法可以通过对时变参数的估算从而对激发机理的变化进行跟踪，对极光亮度测量所得的数据进行处理已经确定了参数变化的存在和说明了它们随时间变化的过程。