1991年6月6日与白光耀斑共生的微波大爆发

本文简要地介绍了发生于２５４５ＭＨＺ和２６４５ＭＨＺ频率上的一次与白光耀斑共生的微波射电大爆发，该爆发有很高的峰值流量，很高的偏振和很复杂的偏振状态的变化，同时该爆发的第一主峰期间同时观测到色球层白光耀斑连续辐射，本文还简要地讨论了这次射电爆发与色球白光耀斑的时间演化关系及射电爆发在主峰期间偏期间偏振状态急剧变化的原因。     

太阳22周峰年期间2545,2645MHzSpike辐射资料分析

本文简要地讨论了１９９１年１月至１２月太阳峰年期间在２５４５、２６４５ＭＨｚ上观测的５１个Ｓｐｉｋｅ辐射事件的高辐射流量、短持续时间、窄辐射带宽、快速频率漂移、准周期振荡和偏振成份快速变化等观测特征，并对这５１个Ｓｐｉｋｅ事件与光学耀斑活动区磁场强度、磁位形及活动区黑子演化类型的密切关系进行了正、反向统计，鉴于Ｓｐｉｋｅ的辐射的观测特征与统计特征与已知的太阳射电爆发类型和太阳射电成分的特征有很大的     

太阳射电辐射事件与Hα耀斑的相关分析

本文统计了１９９０年１月至８月Ｓ．Ｇ，Ｄ〔１５〕发表的８８００ＭＨｚ太阳射电辐射事件、Ｈα耀斑和软Ｘ射线事件。８８００ＭＨｚ射电事件与耀斑相关率达８３．１％，文章还给出了云南天文台米波射电事件与Ｈα耀斑的统计相关结果，并于Ｂｏｕｌｄｅｒ的结果作了比较，详细分折了它们之间的关系。     

太阳射电米波Ⅲ型爆发的观测分析

统计分析了云南天文台在２２周峰年期间观测到的米波Ⅲ型射电爆发与光学活动的关系,发现在２３０～３００ＭＨｚ频率范围的米波Ⅲ型爆发与Ｈα耀斑的关系是密切的,Ⅲ型爆发的产生与双极磁结构和复杂型黑子活动区也密切相关。并对统计结果作了讨论。     

太阳射电米波Ⅲ型爆发的观测分析

统计分析了云南天文台在２２周峰年期间观测到的米波Ⅲ型射电爆发与光学活动的关系,发现在２３０￣３００ＭＨｚ频率范围的米波Ⅲ型爆发与Ｈα耀斑的关系是密切的,Ⅲ型爆发的产生与双极磁结构和复杂型黑子活动区也密切相关。并对统计结果作了讨论。     

太阳白光耀斑的射电辐射特征:运动Ⅳ型爆发和与耀斑后环共生的短周期脉动现象

通过１９９１ 年６ 月６ 日一个复杂的太阳活动事件（ 包括宽带射电运动Ⅳ型爆发、脉冲相伴生的白光耀斑、耀斑后环及其伴生的射电多重短周期（ 约１ － ４ 秒） 脉动现象等） 的分析,探讨了白光耀斑产生的射电辐射特征,根据太阳白光耀斑和射电运动Ⅳ型爆发产生的物理过程,着重讨论了射电运动Ⅳ型爆发、耀斑后环和短周期脉动现象,并认为它们可能是白光耀斑的对应物     

太阳白光耀斑的射电辐射特征：运动Ⅳ型爆发和与耀斑后环共生的短周期脉动

通过１９９１年６月６日一个复杂的太阳活动事件（包括宽带射电运动Ⅳ型爆发、脉冲相伴生的白光耀斑、耀斑后环及其伴生的射电多重短周期（约１－４劝现象等）的分析,探讨了白光耀斑产生的射电辐射特征,根据太阳白光耀斑和射电运动Ⅳ型爆发产生的物理过程,着重讨论了射电运动Ⅳ型爆发、耀斑后环和短周期脉动现象,并认为它们可能是白光耀斑的对应物。     

1991年10月24日白光耀斑的高时间分辨率多波段光谱分析

本分析了南京大学太阳塔１９９１年１０月２４日用多波段光谱仪观测到的高时间分辨率（５ｓ）的一个２Ｎ／Ｘ２．１级白光耀斑光谱，对耀斑谱线轮廓，连续发射强度，Ｘ射线和射电爆发资料进行了综合对比，分析表明，该耀斑属Ｉ类白光耀斑，具有如下特征：（１）在白光耀斑的脉冲相期间，各波段光谱线心强度，连续辐射，谱线半宽以及线翼红不对称性与硬Ｘ射线高能波段的爆分同时达到极大；（２）Ｈα谱线在连续发射极大时半宽达１０     

1991年10月24日白光耀斑的高时间分辨率多波段光谱分析

本文分析了南京大学太阳塔1991年10月24日用多波段光谱仪观测到的高时间分辨率（5s）的一个2N／X2．1级白光耀斑光谱．对耀斑谱线轮廓、连续发射强度、X射线和射电爆发资料进行了综合对比，分析表明，该耀斑属Ⅰ类白光耀斑，具有如下特征：（1）在白光耀斑的脉冲相期间，各波段光谱线心强度、连续辐射、谱线半宽以及线翼红不对称性与硬X射线高能波段的爆发同时达到极大；（2）H_a谱线在连续发射极大时半宽达10A，且呈现强烈的线心反转，H_β和H_γ线心亦有反转；（3）所拍摄的5条谱线都有明显的红不对称性，持续时间约为1分钟，根据上述结果，本文用电子束轰击、色球蒸发和色球压缩区对该耀斑能量积聚和释放的动力学机制作了定性的分析和解释。     

23周峰年云台米波频谱观测系统

本文介绍云南天文台用于观测研究太阳射电２３０ ～３００ ＭＨｚ 米波爆发精细结构动态频谱仪研究的历史和现状,以及利用现代计算机网络技术,有效地解决了由于高时间人辨率和高频率分辩率观测采样带来的大数据量存储和处理。该系统经过不断改进和完善,目前已投入２３ 周峰年太阳射电爆发频谱观测     

The intense microwave burst associated with a white light flare on 1991 June 6

This paper briefly reports on the intense microwave burst associated with a white light flare at 2545 and 2645 MHz on 1991 June 6. The burst had a very high flux density, a very high degree of polarization and very complex changes in polarization state. A chromospheric white light flare was observed during the first peak of the burst. We briefly discuss the time relation between the two and the cause for the changes in polarization.     

Evolvement of microwave spike bursts in a solar flare on 2006 December 13

Solar radio spikes are one of the most intriguing spectral types of radio bursts. Their very short lifetimes, small source size and super-high brightness temperature indicate that they should be involved in some strong energy release, particle acceleration and coherent emission processes closely related to solar flares. In particular, for the microwave spike bursts, their source regions are much close to the related flaring source region which may provide the fundamental information of the flaring process. In this work,we identify more than 600 millisecond microwave spikes which recorded by the Solar Broadband Radio Spectrometer in Huairou(SBRS/Huairou) during an X3.4 solar flare on 2006 December 13 and present a statistical analysis about their parametric evolution characteristic. We find that the spikes have nearly the same probability of positive and negative frequency drifting rates not only in the flare rising phase, but also in the peak and decay phases. So we suppose that the microwave spike bursts should be generated by shockaccelerated energetic electrons, just like the terminational shock(TS) wave produced by the reconnection outflows near the loop top. The spike bursts occurred around the peak phase have the highest central frequency and obviously weak emission intensity, which imply that their source region should have the lowest position with higher plasma density due to the weakened magnetic reconnection and the relaxation of TS during the peak phase. The right-handed polarization of the most spike bursts may be due to the TS lying on the top region of some very asymmetrical flare loops.     

Analysis of the August 7, 1972 white light flare: Light curves and correlation with hard X-rays

Cinematic, photometric observations of the 3B flare of August 7, 1972 are described in detail. The time resolution was 2 s; the spatial resolution was 1–2″. Flare continuum emissivity at 4950 Å and at 5900 Å correlated closely in time with the 60–100 keV non-thermal X-ray burst intensity. The observed peak emissivity was 1.5 × 10¹⁰ erg cm^?2 s^?1 and the total flare energy in the 3900–6900 Å range was ～10³⁰ erg. From the close temporal correspondence and from the small distance (3″) separating the layers where the visible emission and the X-rays arose, it is argued that the hard X-ray source must have had the same silhouette as the white light flare and that the emission patches had cross-sections of 3–5″. There was also a correlation between the location of the most intense visible emissions near sunspots and the intensity and polarization of the 9.4 GHz radio emission. The flare appeared to show at least three distinct particle acceleration phases: one, occurring at a stationary source and associated with proton acceleration gave a very bluish continuum and reached peak intensity at ～ 1522 UT. At 1523 UT, a faint wave spread out at 40 km s^?1 from flare center. The spectrum of the wave was nearly flat in the range 4950–5900 Å. Association of the wave with a slow drift of the microwave emission peak to lower frequencies and with a softening of the X-ray spectrum is interpreted to mean that the particle acceleration process weakened while the region of acceleration expanded. The observations are interpreted with the aid of the flare models of Brown to mean that the same beam of non-thermal electrons that was responsible for the hard X-ray bremsstrahlung also caused the heating of the lower chromosphere that produced the white light flare.     

The flares of July 6 and 8, 1968

From our analysis of the flares of July 6, 1968 and July 8, 1968 the following points emerge: 1) The limb flare of July 6 has been observed in white light for approximately ten minutes during the maximum emission of the electromagnetic radiations. This observation fits the preceding observations of white light flares. The radio flux and radio spectrum hint to the nature of a PF. Corpuscular radiation up to more than 190 MeV has been detected from the spacecraft, Pioneer 6 and Pioneer 7. 2) The region of the proton flare has been characterized by the presence of a Delta magnetic configuration very probably due to the interaction of two different solar centers. This circumstance is quite common in the elaboration of the most active regions. 3) The flare of July 6 has been followed on July 8 by a similar event both for the optical appearance and for the associated electromagnetic radiation. 4) The flare of July 8 has shown the characteristics of the proton flares: coverage of the spots, scission in two ribbons, outstanding radio microwave emission, type IV burst, U radio spectrum etc..., however it has not been followed by a particle flux at the Earth (PCA) or measured in space by the satellites.     

VLA observations of interacting flaring loops

We present 4.9 GHz observations of an impulsive radio burst observed at the Very Large Array on 1981 May 16. The flare occurred in a complex active region containing several spots. The radio burst lay at the edge of an active-region microwave source, close to a neutral line. The compact burst showed morphological evidence for the presence of two loops in the rise phase, with the subsequent burst peak lying between these loops. This suggests that interaction between the loops played some role in the initiation of the flare. The flare spectrum is consistent with thermal gyrosynchrotron emission. The main microwave peak was displaced from the nearest H kernels by about 10, but there is strong evidence for post-flare loops coincident with the H kernels during the later stages of the event.     

The unusual X-ray light curve of GRB 080307: the onset of the afterglow?

Swift -detected GRB 080307 showed an unusual smooth rise in its X-ray light curve around 100 s after the burst, at the start of which the emission briefly softened. This 'hump' has a longer duration than is normal for a flare at early times and does not demonstrate a typical flare profile. Using a two-component power-law-to-exponential model, the rising emission can be modelled as the onset of the afterglow, something which is very rarely seen in Swift -X-ray light curves. We cannot, however, rule out that the hump is a particularly slow early-time flare, or that it is caused by upscattered reverse shock electrons.     

Some studies on solar microwave bursts in relation to the phases of the associated Hα-flares and their spectral nature

Occurrences of the flare-associated microwave bursts as well as their peak flux and energy excess spectra have been examined in relation to the pre- and post-maximum phases of the respective flares during the period 1969–72. Results obtained are: (i) about 76% of the flare-associated bursts occur in the pre-maximum phase and the remaining 24% occurs in the post-maximum phase irrespective of the flare classification, intensity-wise or area-wise; (ii) ‘impulsive’ and ‘gradual rise and fall’ bursts are relatively more important in the pre-maximum phase while ‘post burst increase’ bursts show comparatively higher occurrences in the post-maximum phase; (iii) peak flux and energy excess spectra of the concurrent microwave bursts in the pre-maximum phase of the flare are mostly of ‘inverted U’ and ‘increasing with frequency’ spectral types. Of these, ‘impulsive’ bursts are predominantly of the ‘inverted U’ and the ‘grf’ bursts are of the ‘increasing with frequency’ spectral type.     

Visual and photographic white light flare observations of 4 July 1974

Visual impressions and a photograph of an intense white light flare are presented. A densitometer trace across the 4 July 1974 flare showing relative intensity of the white light flare, photosphere and umbra is also shown. A second white light flare is suspected on a photograph taken 43/4 hrs later. Both flares coincide in time with major H-flare activity.     

Timing analysis of hard X-ray emission and 22 GHz flux and polarization in a solar burst

A solar flare occurring on 26 February, 1981 at 19:32 UT was observed simultaneously in hard X-rays and microwaves with a time resolution of a fraction of a second. The X-ray observations were made with the Hard X-ray Monitor on Hinotori, and the microwave observations were made at 22 GHz with the 13.7 m Itapetinga mm-wave antenna. Timing accuracy was restricted to 62.5 ms, the best time resolution obtained in hard X-rays for this burst. We find that: (a) all 22 GHz flux structures were delayed by 0.2–0.9 s relative to similar structures in hard X-rays throughout the burst duration; (b) different burst structures showed different delays, suggesting that they are independent of each other; (c) the time structures of the degree of polarization at 22 GHz precede the total microwave flux time structures by 0.1–0.5 s; (d) The time evolutions of time delays of microwaves with respect to hard X-rays and also the degree of microwave polarization show fluctuations with are not clearly related to any other time structures. If we take mean values for the 32 s burst duration, we find that hard X-ray emission precedes the degree of microwave polarization by 450 ms, which in turn precedes the total microwave flux by 110 ms.     

The GLE-associated flare of 21 August, 1979

We use a variety of ground-based and satellite measurements to identify the source of the ground level event (GLE) beginning near 06∶30 UT on 21 August, 1979 as the 2B flare with maximum at ～06∶15 UT in McMath region 16218. This flare differed from previous GLE-associated flares in that it lacked a prominent impulsive phase, having a peak ～9 GHz burst flux density of only 27 sfu and a ?20 keV peak hard X-ray flux of ?3 × 10^-6 ergs cm^-2s^-1. Also, McMath 16218 was magnetically less complex than the active regions in which previous cosmic-ray flares have occurred, containing essentially only a single sunspot with a rudimentary penumbra. The flare was associated with a high speed (?700 km s^-1) mass ejection observed by the NRL white light coronagraph aboard P78-1 and a shock accelerated (SA) event observed by the low frequency radio astronomy experiment on ISEE-3.