1.0-2.0GHz,2.6-3.8 GHz微波瀑发与共生HXR瀑发的统计的关系

利用日本YOHKOH卫星HXT提供的HXR爆发资料,和中国科学院北京天文台的太阳射电宽频带动态频谱仪(1.0-2.0 GHz, 2.6-3.8 GHz) 提供的微波爆发资料,对共生事件进行了初步统计分析,并对其中两例典型事件：1997年11月28日0503 UT事件及1998年5月9日0340 UT事件与共生的HXR爆发进行了详细比较,给出了几点有意义的结果及理论解释.     

1.0—2.0GHz,2.6—3.8GHz微波爆发与共生的HXR爆发的统计关系

利用日本ＹＯＨＫＯＨ卫星ＨＸＴ提供的ＨＸＲ爆发资料,和中国科学院北京天台的大亨是射电宽频带动态频谱仪（１．０－２．０ＧＨｚ,２．６－３．８ＧＨｚ）提供的微波爆发资料,对共生事件进行了初步统计分析,并对其中两例典型事件：１９９７年１１月２８日０５０３ＵＴ事件及１９９８年５月９日０３４０ＵＴ事件与共生的ＨＸＲ爆发进行了详细比较,给出了几点有意义的结果及理论解释。     

1992年11月2日的太阳射电爆发事件的特征分析

本文详细地分析了1992年11月2日0233UT发生的太阳大爆发的射电特征,发现此爆发的峰值频谱是U型谱并伴有大的质子事件。爆发过程中,在9.4GHz频率上有快速脉动现象,脉动个数R(重复率)同相应平均流量S之间是紧密相关的。     

1998年4月15日微波爆发观测

北京天文台１ ．０２ ．０ＧＨｚ 太阳射电频谱仪从１９９４ 年开始观测至１９９８ 年９ 月记录到太阳射电爆发１７１ 个,２ ．６３ ．８ＧＨｚ 太阳射电频谱仪１９９６ 年９ 月投入观测至１９９８ 年９ 月,记录到１４６ 个太阳射电爆发。１９９８ 年４ 月１５ 日太阳射电爆发同时在这两台频谱仪上记录到。这个事件在时间和频率上显示了丰富的幅度和结构的变化。发现了微波Ⅲ型爆发对群,并存在着丰富的快速活动现象。取得了高时间分辨率、高质量的动态谱资料,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。     

太阳射电爆发中准周期振荡的研究

自从快速连续采样在太阳射电观测中实现以来,太阳射电爆发资料的研究价值大大提高。如太阳射电尖峰辐射(spike)的存在、用付里叶变换的方法进行准周期振荡的研究等目前在太阳物理研究中存在着争论的问题,可用观测事实加以验证。 1989年5月3日我们取得了一组与X2/3B耀斑共生的spikes及同年8月17日与环珥、HXR、SID对应的射电分米波爆发现象,其射电爆发寿命均大于10分钟。前者的形     

太阳微波爆发中精细结构的统计研究

本文总结了北京天文台1991年的2840MHz波段微波爆发中精细结构（FS）事件的观测．从FS的时间标度、强度、共生的微波爆发的峰值流量、FS发生在微波爆发的相位和FS与Hα耀斑的关系等方面作了统计分析．发现约67％以上的FS其持续时间为几十毫秒到几百毫秒，85％以上的FS幅度小于200sfu．讨论了FS的时标、强度及22周太阳峰年期与21周FS出现率的差别．     

太阳微波M型爆发

分析北京天台１９９８年４月１５日观测到的一个太阳微波Ｍ型爆发事件。Ｍ型爆发实质上是ＩＩＩ型爆发的一个次型,它由两个连续的Ｕ型爆发所组成,即爆发源在同一个磁环中由于磁镜的作用而连续往返运动后的轨迹,但是在低时间分辨率（０．２s）记录资料中却是Ｕ型爆发的形态。因此高时间分辨率（８ms）的记录资料能更准确地反映Ｍ型爆发源的真实运动情况。对比组成Ｍ型爆发的两个Ｕ型爆发,可以看到,该磁环很可能处在下降的演化     

微波Ⅲ型爆发在1-2GHz太阳射电快速频谱仪上的观测

叙述了１９９７年１月至１９９８年４月,使用北京天文台７ｍ射电望远镜在１－２ＧＨｚ频率上观测的微波Ⅲ型爆发的分析结果．共分析６０个事件,获得了单峰、多峰、群集和负吸收微波Ⅲ型爆发的四种型别．通过对它们的频宽、频漂、偏振等重要参量的分析,初步得出微波Ⅲ型爆发在１－２ＧＨｚ上的一些基本特性．     

太阳射电爆发与高能质子加速过程

根据近年来地面和空间观测资料的统计分析指出：（１）太阳质子事件（或质子耀斑）的发生同起伏剧烈的强微波爆发（包括脉冲和ＩＶμ型爆发）或短分米波ＩＶ型爆发存在着紧密的共生关系（共生率趋近１００％）；（２）约有２４％－３０％的质子事件没有对应的ＩＩ型爆发。这一结果否定了以前认为ＩＩ型爆发中的激波加速是产生质子事件必要条件的看法，进而论证了产生强微波（脉冲或ＩＶμ型）爆发的相对论性电子（≥５００ｋｅＶ）与     

太阳微波M型爆发

分析北京天文台１９９８年４月１５日观测到的一个太阳微波Ｍ型爆发事件．Ｍ型爆发实质上是Ⅲ型爆发的一个次型,它由两个连续的Ｕ型爆发所组成,即爆发源在同一个磁环中由于磁镜的作用而连续往返运动后的轨迹,但是在低时间分辨率（０．２ｓ）记录资料中却是 Ｕ型爆发的形态．因此高时间分辨率（８ ｍｓ）的记录资料能更准确地反映Ｍ型爆发源的真实运动情况．对比组成Ｍ型爆发的两个Ｕ型爆发,可以看到,该磁环很可能处在下降的演化阶段．最后讨论该磁环可能的空间分布．     

太阳活动区上空两个微波超快速吸收现象的观测与分析

1987年5月19日世界05h50m17-05k50m25s和1986年6月29日世界时07h38m50s-07h38m58s两个罕见的微波超快速吸收现象分别出现在太阳活动区NOAA／USAF4808和5060上空的3.67GHz和4.00GHz大气层中.当云南天文台高时间分辨率射电望远镜观测到这种吸收现象时,在2.84GHz和1.42GHz大气层中出现的是尖峰辐射,两次超快速吸收现象的显著观测特征是：（1）吸收期的持续时间为20—25ms;（2）吸收的流量范围在17-215s．f.u．;（3）超快速吸收形态与快速吸收形态基本相似;（4）超快速吸收现象均叠加在秒级爆发上,秒级爆发分别为44NS和46C型;（5）相伴随的Ha耀斑分别为SF级和3B级．     

Solar Radio Bursts in the Period Oct. 22-Nov. 4, 2003

A series of solar radio bursts were observed in AR NOAA 10486 withthe Solar Broadband (1.1--7.6 GHz) Radio Spectrometers (SBRS of China). Here weanalyze four significant events associated with CME events and strong X-ray flaresthat occurred on 2003 October 22, 26, 27, 29. The Oct. 26 event is a long durationevent (LDE) with drift pulsation structure (DPS), narrowband dm-burst (DCIM),and more than seven types of Fine Structures (FSs); its time of the maximum flux(07:30 UT) is about half an hour later than the X-flare (06:54 UT).     

太阳短厘米波爆发中双重准周期脉动现象产生的可能机制

1990年5月23日0400—0451UT期间在遥隔两地的南大天文台与北师大天文台和北京天文台用时间分辨率1s和10ms分别在波长3.2cm、2cm和10.6cm上进行了太阳射电爆发的同时观测.发现了短厘米波爆发中的双重准周期脉动现象.本文根据这些观测资料连同S.G.D.发表的有关射电、光学和软X射线(SXR)耀斑等数据,提出了一个在耀(斑)环内非热与热辐射过程中由于相互作用而触发Alfven波和快磁声波的振荡模型,用来解释太阳短厘米波爆发中相关性很强的双重准周期脉动的起因和观测特征,并由此计算出爆发源区的平均物理参量T,N,B值。     

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.     

Perturbation of nuclear decay rates during the solar flare of 2006 December 13

Recently, correlations have been reported between fluctuations in nuclear decay rates and Earth–Sun distance, which suggest that nuclear decay rates may be affected by solar activity. In this paper, we report the detection of a significant decrease in the decay of ⁵⁴Mn during the solar flare of 2006 December 13, whose X-rays were first recorded at 02:37 UT (21:37 EST on 2006 December 12). Our detector was a 1 μCi sample of ⁵⁴Mn, whose decay rate exhibited a dip coincident in time with spikes in both the X-ray and subsequent charged particle fluxes recorded by the Geostationary Operational Environmental Satellites (GOES). A secondary peak in the X-ray and proton fluxes on December 17 at 12:40 EST was also accompanied by a coincident dip in the ⁵⁴Mn decay rate. These observations support the claim by Jenkins et al. that nuclear decay rates may vary with Earth–Sun distance.     

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.     

Microwave and hard X-Ray observations of a solar flare with a time resolution better than 100 ms

Simultaneous microwave and X-ray observations are presented for a solar flare detected on May 8, 1980 starting at 19:37 UT. The X-ray observations were made with the Hard X-Ray Burst Spectrometer on the Solar Maximum Mission and covered the energy range from 28–490 keV with a time resolution of 10 ms. The microwave observations were made with the 5 and 45 foot antennas at the Itapetinga Radio Observatory at frequencies of 7 and 22 GHz, with time resolutions of 100 ms and 1 ms, respectively. Detailed correlation analysis of the different time profiles of the event show that the major impulsive peaks in the X-ray flux preceded the corresponding microwave peaks at 22 GHz by about 240 ms. For this particular burst the 22 GHz peaks preceded the 7 GHz by about 1.5 s. Observed delays of the microwave peaks are too large for a simple electron beam model but they can be reconciled with the speeds of shock waves in a thermal model.     

Multiple-loop structure of a solar flare from Microwave,EUV and X-ray Imaging Data

We present the results of an analysis of a flare event of importance M2.8 that occurred at 00:56 UT 28 August 1999. The analysis is based upon observations made with the Nobeyama radioheliograph (NoRH) and polarimeters (NoRP), TRACE, SOHO/MDI, EIT, and Yohkoh/SXT. The images show a very complex flaring region. Pre-flare TRACE and EIT images at 00:24 UT show a small brightening in the region before the flare occurred. The active region in which the flare occurred had evolving magnetic fields, and new magnetic flux seems to have emerged. The X-ray and radio time profiles for this event show a double-peaked structure. The polarimeter data showed that the maximum radio emission (1200 s.f.u.) occurred at 9.4 GHz. At 17 GHz the NoRH images appear to show four different radio sources including the main spot and the main flare loop. Most of the microwave emission seems to originate from the main flare loop. Comparison of BATSE and microwave time profiles at 17 and 34 GHz from the main sunspot source shows that these profiles have similar structures and they coincide with the hard X-ray peaks. The maximum of the flare loop emission was delayed by 10 s relative to the second maximum of the sunspot associated flare emission. Analysis of SXT images during the post-flare phase shows a complex morphology – several intersecting loops and changes in the shape of the main flare loop.     

Hard X-rays and associated weak decimetric bursts

In previous attempts to show one-to-one correlation between type III bursts and X-ray spikes, there have been ambiguities as to which of several X-ray spikes are correlated with any given type III burst. Here, we present observations that show clear associations of X-ray bursts with RS type III bursts between 16:46 UT and 16:52 UT on July 9, 1985. The hard X-ray observations were made at energies above 25 keV with HXRBS on SMM and the radio observations were made at 1.63 GHz using the 13.7m Itapetinga antenna in R and L polarization with a time resolution of 3 ms. Detailed comparison between the hard X-ray and radio observations shows:

1. In at least 13 cases we can identify the associated hard X-ray and decimetric RS bursts.
2. On average, the X-ray peaks were delayed from the peak of the RS bursts at 1.6 GHz by ～ 400 ms although a delay as long as 1 s was observed in one case.

One possible explanation of the long delays between the RS bursts and the associated X-ray bursts is that the RS burst is produced at the leading edge of the electron beam, whereas the X-ray burst peaks at the time of arrival of the bulk of the electrons at the high density region at the lower corona and upper chromosphere. Thus, the time comparison must be made between the peak of the radio pulse and the start of the X-ray burst. In that case the delays are consistent with an electron travel time with velocity ～ 0.3 c from the 800 MHz plasma level to the lower corona assuming that the radio emission is at the second harmonic.     

Repetition rates of fast pulses in a solar burst observed at MM-waves and hard X-rays

The solar burst of 21 May, 1984, 13 26 UT, showed radio spectral emission with a turnover frequency above 90 GHz, well correlated in time with the hard X-ray emission. It consisted of seven major time structures (1–3 s in duration), of which each was composed of several fast pulses with rise times between 30 and 60 ms. The spectral indices of the millimeter and hard X-ray emission exhibited sudden changes during each major time structure. The subsecond pulses were nearly in phase at 30 and 90 GHz, but their relative amplitude at 90 GHz ( 50%) were considerably larger than at 30 GHz (<5%). It was also found that the 90 GHz and the 100 keV X-rays fluxes were proportional to the repetition rate of the subsecond pulses, and that the hard X-ray power law index hardens with increasing repetition rate.Proceedings of the Second CESRA Workshop on Particle Acceleration and Trapping in Solar Flares, held at Aubigny-sur-Nère (France), 23–26 June, 1986.