AR5395活动区演化的周期性

观测资料分析表明,AR5395活动区演化具有周期性的特征,软X射线峰值流量F变化周期为24.3小时,X射线耀斑出现率N_x,具有12.2小时的周期性,活动区黑子群面积S_x的变化呈现24.4小时的周期。这3个周期变化量的相位关系表明:(1)X级耀斑往往发生在黑子面积减小的位相;(2)在1个周期内,黑子群面积达到最大值约需16小时,恢复到大耀斑前水平约需8小时;(3)在X级大耀斑前约12小时,小级别耀斑出现率达到峰值。分析显示,AR5395活动区似乎工作于大耀斑能量储存—释放—储存周期性循环的极限状态之中。      

太阳X射线耀斑活动区的一些特征

对ISEE-3人造卫星在1980年5月—1981年8月中,观测到的48个X射线耀斑进行了分析,发现其中有1/3是在6个活动区中重复爆发的.研究这部分X射线耀斑的物理性质与所在活动区的黑子面积、活动区类型及磁结构的关系,得到了一些结果:(1)发生在同一活动区中的X射线耀斑,其硬X射线峰值积分流量及谱硬度与活动区黑子面积成正相关;(2)多次爆发X射线耀斑的活动区全部具有δ型磁结构;(3)发生在不同活动区中的X射线耀斑,其物理特征与所在活动区的面积大小无明显关系.由此可以认为,活动区磁场梯度的大小,亦即活动区电流的大小,在爆发耀斑的过程中具有决定性作用.此外,还用电流环模型从理论上讨论了上述特征.     

太阳质子耀斑X射线辐射特征及质子事件警报

太阳质子耀斑X射线辐射特征的研究, 为太阳质子事件的警报提供一个重要的途径和方法。本文分析了第21周太阳活动峰年(1977—1986)期间质子耀斑和相应的GOES和SMM卫星观测的X射线辐射资料, 结果表明:大部分质子耀斑的硬X射线峰值流量F_HX≥104s/c;积分流量F₀≥106counts;硬X射线辐射到达峰值时间T_R≥100s;持续时间T_D≥103s;X光子最高能量E_x≥300keV;平均能谱指数√r≤3.5;高能时延T_L≥10s。利用这些X射线暴的特征参数, 对第21周峰年大质子事件作警报检验, 结果是:报准率为94％, 虚报率为40％。      

第21～24太阳周4类空间天气事件爆发特征统计分析

对第21～24太阳周不同等级的太阳X射线耀斑事件、太阳质子事件、地磁暴事件及高能电子增强事件的爆发频次特征进行统计,结果表明:太阳周耀斑爆发的总数量与该太阳周的黑子数峰值呈正比,耀斑总数、X级耀斑事件数与峰值的相关系数分别为0.974,0.997;太阳质子事件主要发生在峰年前后1～2年,约占总发生次数的80%,峰值通量大于10pfu （1 pfu=1 cm-2·sr-1·s-1）的质子事件中,84%伴有耀斑爆发,并且主要伴随M或X级耀斑,少量伴随C级耀斑,峰值通量大于1000pfu的质子事件中,98%伴随M或X级耀斑,并且以X级耀斑为主;第21,22,23和24太阳周发生地磁暴最频繁的时间分别在1982,1991,2003年和2015年,分别滞后黑子数峰值时间3年、2年、2年和1年;72%的高能电子增强事件发生在太阳周下降期,24%的高能电子增强事件发生在太阳周上升期.      

SMY和第21太阳周期间地磁及太阳活动特点的分析

本文比较第17—21太阳周黑子数、地磁A_p指数、各周极大年≥2级耀斑数、磁暴数及第一、二、三大磁暴情况;分析了≥2级耀斑数及磁暴的分布。21周3级耀斑对应磁暴比例低于19、20周,Ⅳ型及米波射电爆发是产生磁暴的重要条件。进一步分析了21周最大磁暴、最大射电爆发引起的磁暴,最严重的电离层短波通讯干扰及有明亮物质抛射的大耀斑、双带大耀斑引起的磁暴等典型例子。最后对SMY期间22个无黑子耀斑作了分析,它们可能引起中小幅度的磁暴。      

关于冲击波在环形磁场中的传播

本文求解了点源爆炸波在环形磁场中传播的非自型问题。以耀斑引起的击波传播为例讨论了解的应用。从中可以看到,磁场扰动呈U形,主要发生在0.5Re—1.0Re的击波区域;行星际磁场的存在使击波到达1AU的时间延长了几个小时;击波必须具有大于磁截止能量E_M=λ₁S2/4π J₀R时(符号意义见内容)才有可能传播到1AU以远的地方,日冕磁场结构对耀斑击波进入行星际空间的传播有重要作用。      

无黑子耀斑的形态特征及其可能的理论模型

本文汇总了我国三个天文台(云台、紫台、北台)在21周峰年期间所观测到的无黑子耀斑的形态特征。然后,在日珥的Kippenhahn-schIuter模型的基础上,定性地解释了这些无黑子耀斑的观测特征,并从理论上提出了产生无黑子耀斑的一种可能模型。     

海南岛三亚哨声观测资料的初步分析

本文主要介绍1983年初在海南岛三亚观测哨声的部分结果.记录到大量哨声,其中包括短哨、多源哨和多路哨;约有10%的哨声下截频在0.8kc/s左右.经分析发现:(1)三亚哨声几乎全部出现在f₀F₂下降的过程中,哨声出现率的峰值在f₀f₂下降最快处,即电子浓度下降变化急剧处;(2)哨声活动和磁暴的关系与中高纬有所不同,存在明显的相反情况.      

电离层电场对磁层活动响应时延的模式研究

本文用极盖边界上电离层驱动电位φ₀随时间变化的不同模式计算了场向电流J_∥2及电离层对流电场E的演化过程。计算表明,当φ₀(t)先升后降有极大值时,J_∥2(t)和E(t)也表现出类似的趋势。但它们的极值滞后于φ_0max出现的时刻,即在一段时间内,φ₀虽已开始下降,J_∥2及高纬E却继续增大。一般说,E先于J_∥2达到极值,但相差甚小。φ₀变化形式不同时,滞后时间亦不同。当φ₀陡升缓降时,E、J_∥2的极值相对于φ_0max的时延可超过一小时。这与持续时间较长的磁暴期间所观测到的电离层场强响应时延量级是一致的。时延大小还受电离层电导率的制约。低纬电离层场强的响应与高纬不同,其升降趋势与φ₀同步。      

冲击波在变密度、运动介质中的传播

本文得到了点源爆炸波在变密度、运动介质中传播的分析解(ω=2,γ=5/3),讨论了耀斑引起的击波在太阳风中传播的一些特性。发现1AU附近区域恰是击波各种重要效应的过渡区;击波减速等效指数i(D=K(u_o,E_s)R-i(u_o,E_s,R))是介质运动速度u_o.击波能量E_s,和击波传播距离R的函数,通常是小于1/2的,不是自型理论预言的那样简单;太阳风的对流效应使击波可以传播到10-20AU以远,与飞船(先躯者10、11号)新近的观测相吻合。      

Imaging polarimetry of Hα kernels of solar flares with a ferroelectric liquid crystal polarimeter

Impact polarization of the kernels of solar flares in the chromospheric lines is one of the important diagnostics of high-energy particles in solar flares. Even though so far the detection of polarization up to 10% have been reported by various authors, generally the polarization of the flare kernels is small. To detect the impact polarization, high-cadence imaging polarimetry with the precision of the order of 0.1% is required. The seeing-induced error is the greatest cause degrading the polarimetric precision, but it can be reduced by high-frequency polarization modulation. We developed a polarimeter with ferroelectric liquid crystals (FLCs) combining with a high-speed CCD camera, and the modulation frequency as high as 1 kHz realized the precision of the polarimetry in the Hα line of the order of 0.1%. Many flares have been observed with this polarimeter, and we found that just small flares sometimes show significant polarization. However, the majority of the flares do not show polarization signals larger than 0.1%. Our results suggest that there are some unknown parameters to produce the polarization of flare kernels.     

1984年5月21日耀斑环珥的Hα-SSHG观测研究

利用云南天文台太阳光谱分光照相仪(Hα-SSHG),拍摄了1984年5月21日边缘耀斑环珥的Hα光谱资料,结合Hα色球观测资料给出了该事件的发展过程和色球、光谱的形态特征。定性地探讨了该耀斑环内的宏观物质运动.用提出的双环系模型能较好地解释观测结果.      

An investigation of small GOES flares with intense hard X-ray bursts

Most solar flare observations show that intense hard X-ray bursts come from large flares that have a large GOES classification (large peak 1 – 8 Å flux). This correlation, known as the “Big Flare Syndrome”, suggests that more intense flares tend to have harder spectra. We have observed 7 flares that are exceptions to this. These flares have small GOES classifications ranging from B1.4 to C5.5 and peak hard X-ray count rates similar to those often observed from M class flares. This paper examines the cause of this anomoly using the Yohkoh Soft X-Ray Telescope, Hard X-Ray Telescope, and Bragg Crystal Spectrometer. Two hypotheses are proposed for the exceptions: (1) flares with multiple magnetic loops and common footpoints, producing multiple hard X-ray emission regions and low density thermal plasma distributed over a large volume, and (2) high densities in the magnetic loops restricting the propagation of the non-thermal electrons in the loop after magnetic reconnection has occurred and suppressing chromospheric evaporation. Two of the flares support the first hypothesis. The other flares either have data missing or are too small to be properly analysed by the Yohkoh instruments.     

1986年2月太阳的高活动I活动区4711的演化和特征

本文使用太阳黑子、磁场、Hα色球、10.7cm射电及软X射线流量等观测资料,对太阳活动谷期的高活动区4711(SESC编号)从光球、色球和日冕三个方面做了综述.指出该活动区演化过程的特征是:(1)黑子群在主要发展阶段呈一个紧密的结构复杂的强磁区;(2)两次大的太阳爆发均发生在黑子群面积衰减阶段的初期;(3)黑子群的转动可能是活动区日冕加热和耀斑活动的主要供能机制;(4)色球暗条的频繁活动是爆发的先兆;(5) 10.7cm射电辐射和软X射线辐射的逐日流量有彼此不重合的双峰.      

一个亚耀斑的精细结构与演化

本文对1981年5月8日16h13mUT开始的-N级Hα耀斑进行了图象处理,画出了等光度图。在此基础上,采用二种光度测量法:一是定点法,相对于日面上稳定的定点(～1″),测出50个亮点的位置及其光度变化;另一是亮点跟踪法,测出每一时刻最亮点的位置,看位置的变动。从而得到耀斑的精细结构与演化过程。      

Recurrent mass ejections observed in Hα and CIV

Time sequences of recurrent mass ejections have been observed during a coordinated SMY program (1 Sept. 1980 – 23 Sept. 1980 – 2 Oct. 1980).Comparison of the temporal evolution of H_α and CIV brightnesses shows a weak phase lag between H α and CIV maxima, in the case of homologous flares, with CIV brightness maxima preceding H α maxima. The analysis of the variation of the ejection velocities is expected to lead to the determination of an energy balance.Such recurrent ejections could be due to periodic energy storage and periodic reorganisation of magnetic field as envisaged to occur for flares, but at lower energy levels.     

On the correlation of microwave bursts with the Hα flares

High correlation between microwave bursts and H_α flares has already been reported. However, Solar Maximum Year cooperation made it possible to do simultaneous observations of selected active regions with good spatial resolution. In this paper the results of the direct comparison of solar microwave recordings at the Metsähovi Radio Research Station and H_α films at the Hvar Observatory are reported. This comparison reveals that the correlation of microwave gradual rise and fall (GRF) events (time scale tens of minutes) with H_α flares is practically 100 percent. On the other hand the correlation of the impulsive microwave bursts (time scale tens of seconds) with H_α flares is low. From this it can be concluded that the main contribution to the microwave GRF bursts comes from thermal radiation.     

The relationship between inductive electric field and flares

We observationally deduce the inductive electric field in the photosphere for the first time from the horizontal velocities computed by local correlation tracking (LCT) technique and the vector magnetic fields derived from vector magnetograms. We study the relationship between E and powerful flares (X-class) of four active regions (ARs): NOAA 10720, 10486, 9077 and 8100. It is found that the kernels of flares are roughly located near the inversion lines where maxima of E are observed. Our results show that E relates to the accumulation of non-potentiality in the photosphere and the transportation of non-potentiality from the photosphere to the corona.     

Spectral evolution in gamma-ray bursts

The Hard X-ray Burst Spectrometer (HXRBS) and the Gamma-Ray Spectrometer (GRS) on NASA's Solar Maximum Mission satellite (SMM) have independently monitored cosmic gamma-ray bursts since launch in February 1980. Several bursts with relatively simple pulse structure and sufficient intensity have been analyzed for evidence of spectral variability on timescales shorter than the pulse durations. In many of these bursts we find pulse structures, ranging in duration from 1 to 10 seconds, which exhibit a trend of hard-to-soft spectral evolution. No significant evidence for soft-to-hard evolution has been found, although the possibility of weak, extended low-energy emission is suggested in a few bursts. The HXRBS data above 100 keV and the GRS data above 1 MeV indicate that the spectral evolution generally is not due to time-varying absorption features at energies below 100 keV.     

X级以上耀斑与地磁效应关系研究

统计研究了2010年1月至2012年12月期间所有与耀斑爆发相伴生的日冕物质抛射(CME) 引发的地磁暴事件. 结果表明, 对于CME源区其主要分布在日面 45°E-45°W, 占总数的78.95%, 且西半球比东半球多, 即源区位于西半球的CME易产生地磁效应; X级耀斑与地磁效应的关联性更高, 60.0%的 X级耀斑在其爆发后的2～3天内观测到地磁暴, 而其他级别的耀斑与地磁效应的关联性低得多, 均不足10%; 通过对此期间日面爆发的所有X级耀斑研究分析后发现, 对于源区位于日面东经45°E-45°W 的X级耀斑, 若在其爆发过程中没有大尺度日面扰动, 则无伴生CME且后续产生地磁效应的可能性很低. 由此提出一种通过分析日面观测数据进行地磁暴预报的方法.