太阳微波爆发频谱事件

国家天文台1.0-2.0GHz,2.6-3.8GHz太阳射电频谱仪从1994年1月和1996年9月投入观测至2000年4月10日记录到太阳射电爆发分别为297个和316个，取得了高质量的高时间分辨率，高频率分辨率的动态谱资料，为研究耀斑各种尺度的时间及空间演化过程提供了丰富的信息，1998年4月15日的共同事件在时间和频率上显示了丰富的幅度和结构的变化。     

太阳微波射电快速精细结构亚类型的观测分析

通过分析"云南天文台4波段太阳射电快速同步观测系统"1990-01-1994－01取得的103个射电爆发,发现其中29个存在不同类型的快速精细结构（FFS）.尤其是发现了几个少见的亚类FFS现象.本文仅介绍两个亚类型:窄带变周期脉动和宽带慢漂移长周期脉动.这些现象表明太阳射电FFS的多样性,它们发生在射电爆发的不同阶段（耀斑不同相）,从而说明在耀斑演化中日冕非热电子的加速或注入可能贯穿于整个耀斑发展过程.由于耀斑后相FFS的发生,可验证耀斑后相存在磁重联和似环结构（耀斑后环）的重新形成.由于不同的亚类FFS反映日冕中存奇特别的环境条件,从而推测日冕中可能存在更复杂的多重类型的磁结构.      

快变分量观测与基本分量特性

本文对太阳２２周峰年期云南天文台日冕射电频谱仪观测到的６０个快速事件作了分析。从中获得了尖峰辐射、增强噪暴、快速起伏、类尖峰、叠加脉冲五种快变型别，对它们的亮温度、叠加特性、特征时间、辐射源尺度、偏振特性以及辐射机制六个方面作了分析研究后，对射电爆发、缓变分量和宁静太阳的辐射特征参量也作了研究，从而得出基本分量特性。     

米波Ⅲ型爆发与日冕物质抛射

对澳大利亚Culgoora天文台射电频谱仪在太阳活动第23周峰年期间记录到的米波Ⅲ型爆发(20～420 MHz),与日冕物质抛射(CME)、Hα耀斑及相关事件进行了统计分析,发现米波Ⅲ型爆发与CME的关系没有Ⅱ、Ⅳ型爆发与CME的关系密切;米波Ⅲ型爆发发生的时间在CME之前25～30 min最多;72%的CME事件伴随长寿命的Hα耀斑.从这些观测特征出发,对米波Ⅲ型爆发、CME和Hα耀斑进行了定性的解释.      

太阳射电爆发干扰导航通信机理及影响表征分析

太阳射电爆发是一种潜在的导航系统干扰因素。通过导航信号模型推导,分析了其干扰导航信号的机理,提出太阳射电爆发干扰导航通信的影响方程与太阳射电爆发流量、接收机性能以及太阳–天线高度角有关,其中太阳射电流量总功率与信号的信噪比下降呈正相关;同时受到太阳–天线高度角和有效面积的制约,又与接收机环路滤波器响应函数呈卷积关系。通过对2003年10月28日、2006年12月6日和2015年11月4日事件中GPS失锁情况分析,发现同一次事件中同一站点不同接收机的失锁率不同;同一次事件中不同纬度的接收机失锁率不同,以及在同一次事件中L波段（1～2 GHz）太阳射电爆发频谱不均匀的条件下,L1和L2频段信号的信噪比下降情况也不同。从上述三个事件的观测表征验证了上述影响方程的分析正确性。     

在月球背面进行低频射电天文观测的关键技术研究

月球具有足够大的尺寸,能够有效地遮挡来自地球的低频电磁波干扰,因此月球背面是进行低频射电天文观测的最佳场所。本文论述了利用低频射电频谱仪在月球背面进行空间低频射电天文观测的意义,给出了低频射电频谱仪工作原理、科学探测目标和系统组成。研究了低频射电频谱仪的设计,并采用低频射电频谱仪对北京中关村地区空中低频电磁波辐射频谱进行了试验探测,结果表明:低频射电频谱仪能够清晰地探测到0.1~40 MHz频带内的广播电台及授时台等发射的低频电磁波信号。     

AR5395和AR5629X射线事件的太阳射电辐射特征

ＡＲ５３９５和ＡＲ５６２９Ｘ射线事件的太阳射电辐射特征吴洪敖，孙九祯（中同科学院紫金山天文台，南京２１０００８）关键词太阳耀斑，Ｘ射线事件，射电事件一、概况本文选用的典型事件是１９８９年３月的ＡＲ５３９５和８月的ＡＲ５６２９的射电缓变和爆发分量，及其...     

太阳射电微波爆发的频谱分析

1981年4月1日太阳发生一个4N级Hα耀斑并伴随出现强烈的IV型射电爆发.本文对北京天文台,西澳大利亚站等射电资料进行分析.分析表明:(1)该事件的微波源状态相对稳定,米波源位置存在移动,因此产生微波辐射与米波辐射是两组不同的电子群体,在爆发频谱指数的时变曲线上表现出明显的形态差异.还由于两者辐射源的位置不同,微波与米波的爆发在峰值时刻上也不完全符合.(2)4月1日微波大爆发是由三个主爆发组成的,它们的峰值时刻分别为0135.1,0146.1,0153.6UT.由射电高频端谱指数算出的非热电子能谱指数表明,在射电爆发的三个峰值时刻电子能谱都变硬.本文还得出该活动区的非热电子平均速度(以光速c为单位)β为0.9左右,磁场强度B为430G.并由回旋同步辐射阻尼算得,非热电子的寿命为829秒,这个数值与三个主峰的持续时间相吻合.     

射电爆发显著事件与Ⅱ型爆发

本文分析了北京天文台2840MHz射电望远镜,1989年1月-1993年12月期间观测到的太阳射电爆发的显着事件与米波Ⅱ型、Ⅳ型爆发的对应关系,从相关结果来看,爆发的峰值流量越高△T越短,这说明当太阳流量越大,高达500s.f.u.以上时,Ⅱ型爆发会在爆发的峰值前后很短时间内发生,可能与粒子的加速有关。      

同无黑子耀斑相协的微波爆发机制的探讨

1980—1984年期间,我们在云南天文台9375MHz,3653MHz和2902 HHz三个波段的射电观测资料中,查到11组微波爆发与无黑子耀斑相伴随。本文研究了这些爆发与耀斑的大气层高度,射电爆发类型以及通过落进峰值流量-时间图的位置,确认出爆发机制是活动区中作麦克斯韦分布电子的热轫致辐射。     

Impulsive acceleration during gradual type solar radio flares

Gradual rise and fall type solar radio flares recorded at 37 GHz (8 mm wavelength) are analysed and compared with simultaneous soft and hard X-ray events. Emission measures and plasma temperatures were calculated from the GOES soft X-ray data, and optically thin thermal bremsstrahlung flux at 37 GHz was calculated assuming the same emitting volumes. The main emission mechanism behind the millimeter wave radio flares was determined to be thermal bremsstrahlung although many of the flares showed impulsive, non-thermal features. The radio flares were compared with simultaneous BATSE hard X-ray events, but significant temporal correlation was not found. It is suggested that there might be two different types of gradual radio flares, connected to gradual or more impulsive hard X-ray events. Another explanation for the observed two types would be different viewing angles to the emitting regions.     

Radio fine structures in dm–cm wavelength range associated with magnetic reconnection processes

Radio bursts with fine structures in decimetric–centimetric wave range are generally believed to manifest the primary energy release process during flare/CME events. By spectropolarimeters in 1–2 GHz, 2.6–3.8 GHz, and 5.2–7.6 GHz at NAOC/Huairou with very high temporal (1.25–8 ms) and spectral (4–20 MHz) resolutions, the zebra patterns, spikes, and new types of radio fine structures with mixed frequency drift features are observed during several significant flare/CME events. In this paper we will discuss the occurrence of radio fine structures during the impulsive phase of flares and/or CME initiations, which may be connected to the magnetic reconnection processes.     

太阳耀斑对电离层总电子含量的影响

本文分析了1978—1979年1级以上的太阳耀斑对电离层总电子含量的影响. 给出了不同持续时间、不同亮度、不同季节、发生在日面不同位置上的太阳耀斑对电离层总电子含量的影响.分析结果表明,持续时间大于等于1.5小时的耀斑对电子含量有明显的扰动,耀斑出现后电子含量随之增加,在第4—5天增加到最大值,扰动持续数日;持续时间小于1.5小时的耀斑对电子含量影响甚微;非亮耀斑对电子含量的扰动小于亮耀斑;夏季出现的耀斑对电子含量无明显扰动,只有冬季出现的亮耀斑对电子含量有明显的扰动;太阳耀斑扰动电子含量有明显的日面位置东西不对称性,只有出现在日面东边、特别是E₃区的太阳耀斑对电子含量才有明显的扰动.      

The evolution of a complex solar radio burst corresponding to special configuration of microwave sources

A complex radio burst associated with periodic (∼1 and 6 min) pulsations and several kinds fine structures, e.g., normal- and reverse-drifting type III bursts, zebra patterns, and slowly drifting structure was observed with the radio spectrometers (1.0–2.0, 2.6–3.8, 5.2–7.6, and 0.65–1.5 GHz) at the National Astronomical Observatories of China (NAOC) in Beijing and Yunnan on 19 October 2001. In combination with the images of 17 and 34 GHz from NoRH and the magnetograms from MDI we reveal the existence and evolution of preexisting and new emerging sources, and find the horseshoe-shaped structure of microwave sources intensity during the late phase of the burst. Through the detailed comparison of the evolution of each source with the time profiles of radio bursts corresponding to these sources we indicate that the intimate correlation between the microwave sources evolution and the generation of the radio burst associated fine structures. Some fine structures can be considered as the MHD turbulence and plasma emission mechanism, based on the anisotropic beam instability and hybrid waves generations. From the characteristics of observations we may presume that the coronal magnetic structures should contain an extended coronal loop system and multiple discrete electrons acceleration/injection sites. The mechanisms of this complex radio burst are deal with the incoherent gyrosynchrotron emission from the trapped electrons and the coherent plasma emission from the non trapped electrons.     

Relationship of solar flare accelerated particles to solar energetic particles (SEPs) observed in the interplanetary medium

Observations of hard X-ray (HXR)/γ-ray continuum and γ-ray lines produced by energetic electrons and ions, respectively, colliding with the solar atmosphere, have shown that large solar flares can accelerate ions up to many GeV and electrons up to hundreds of MeV. Solar energetic particles (SEPs) are observed by spacecraft near 1 AU and by ground-based instrumentation to extend up to similar energies as in large SEP events, but it appears that a different acceleration process, one associated with fast coronal mass ejections is responsible. Much weaker SEP events are observed that are generally rich in electrons, ³He, and heavy elements. The energetic particles in these events appear to be similar to those accelerated in flares. The Ramaty high energy solar spectroscopic imager (RHESSI) mission provides high-resolution spectroscopy and imaging of flare HXRs and γ-rays. Such observations can provide information on the location, energy spectra, and composition of the flare accelerated energetic particles at the Sun. Here, preliminary comparisons of the RHESSI observations with observations of both energetic electron and ion near 1 AU are reviewed, and the implications for the particle acceleration and escape processes are discussed.     

X级质子耀斑的特征研究

为了更加准确地判断X级耀斑是否引发质子事件,对X级质子耀斑和非质子耀斑的耀斑积分通量、源区、CME速度、CME角宽度、背景太阳风速度及背景X射线通量的分布进行了统计研究.发现非质子耀斑和质子耀斑的积分通量、经度、CME速度和CME角宽度具有明显不同的分布.非质子耀斑大多集中在东部,耀斑积分通量小于0.3J·m-2,CME速度小于1300km·s-1的区域内;质子耀斑大多集中在中部或西部,耀斑积分通量大于0.3J·m-2,CME速度大于1300km·s-1的区域内.质子耀斑伴随的CME角宽度主要集中在360°,非质子耀斑的CME角宽度分布则相对分散.两类耀斑的背景太阳风速度和背景X射线通量分布差别不大.利用两类耀斑各个参量分布上的差异,有望提高X级耀斑预报的准确率.      

一种新的太阳质子事件警报方法的探讨

本文分析了第21太阳活动周后半期的太阳质子耀斑硬X射线辐射资料, 发现它们的峰值流量、积分流量、上升沿斜率、X光子的最高能量和持续时间等物理参数之间有着不同于非质子耀斑的相关性。据此, 本文采用模糊聚类分析法, 对21太阳活动周期间(1980.2—1986.2)的质子事件进行预报试验。其报准率为88.5%, 虚报率为53.1%, 漏报率为11.5%。本文提供了基于X射线辐射特征的太阳质子事件警报的新途径和方法。      

Great solar bursts of October 19, 22 and 23, 1989

Itapetinga measurements at 48 GHz with the multibeam technique are used to determine the relative position of solar burst centroid of emission with high spatial accuracy and time resolution. For the Great Bursts of October 19,22, 1989, with a large production of relativistic particles, and October 23, it is suggested that, at 48 GHz, the bursts might have originated in more then one source in space and time. Additionally the October 19 and 22 Ground Level Events exhibited very unusual intensity-time profiles including double component structures for the onset phase. The Bern observatory spectral radio emission data show a strong spectral flattening typical for large source inhomogeneties. The interpretation for this is that large solar flares are a superposition of a few strong bursts (separated both in space and time) in the same flaring region.     

三种类型的质子耀斑

根据SMM卫星观测资料,分析了GRL,PE和GRL/PE三种类型质子耀斑在硬X射线辐射特征上的差异。结果表明,存在的差异与粒子加速区(或作用区)分别处于不同的日面高度有关。