共查询到18条相似文献,搜索用时 120 毫秒
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1986年2月太阳的高活动I活动区4711的演化和特征 总被引:1,自引:1,他引:0
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. 相似文献
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同无黑子耀斑相协的微波爆发机制的探讨 总被引:1,自引:0,他引:1
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。 相似文献
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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. 相似文献
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太阳微波爆发动态频谱仪 总被引:2,自引:1,他引:1
介绍了北京天文台已投入观测的1.0—20GHz,2.6—3.8GHz太阳射电频谱仪及1999年投入观测的5.2—76GHz太阳射电频谱仪。它们是第23周太阳活动峰年我国太阳物理界的重要观测设备已投入观测的频谱仪获得不同类型的太阳射电爆发资料分别为171个和146个,这些事件在时间和频率上有丰富的幅度和结构的变化。不同太阳射电爆发反映太阳大气不同高度上耀斑的时间和空间的演化过程,为研究不同大气高度中耀斑物理动力学过程、能量释放、粒子加速提供了更多的依据。 相似文献
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利用AR2522活动区多波段的观测资料,分析了暗条演化与1B/M4级双带耀斑爆发之间的关系。结果表明:(1)足点的剪切运动导致暗条电流增强和耀斑贮能;(2)暗条上升运动和绞扭现象是暗条电流增强和耀斑贮能的结果;(3)Marttens-Kuin模型至少适合于解释与暗条快速上升有关的双带耀斑爆发。 相似文献
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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. 相似文献
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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. 相似文献
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Xuan Jiayu Li Zhi Gu Xiaoma Li Weibao Xu Aoao Tang Yuhua 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(11):221-224
The active region morphology and the features of solar radio bursts and sight-line velocity distribution of a flare of Importance 3B on the solar disc (AR 2562) on 1980 July 14 are introduced in this article. 相似文献
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Hard X-ray and high-frequency decimetric radio observations of the 4 April 2002 solar flare 总被引:1,自引:0,他引:1
S.R. Kane H.S. Sawant J.R. Cecatto M.C. Andrade F.C.R. Fernandes M. Karlicky H. Meszarosova 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2003,32(12):2503-2508
Hard X-ray and high frequency decimetric type III radio bursts have been observed in association with the soft X-raysolar flare (GOES class M 6.1) on 4 April 2002 (1532 UT). The flare apparently occurred 6 degrees behind the east limb of the Sun in the active region NOAA 9898. Hard X-ray spectra and images were obtained by the X-ray imager on RHESSI during the impulsive phase of the flare. The Brazilian Solar Spectroscope and Ondrejov Radio Telescopes recorded type III bursts in 800–1400 MHz range in association with the flare. The images of the 3–6, 6–12, 12–25, and 25–50 keV X-ray sources, obtained simultaneously by RHESSI during the early impulsive phase of the flare, show that all the four X-ray sources were essentially at the same location well above the limb of the Sun. During the early impulsive phase, the X-ray spectrum over 8–30 keV range was consistent with a power law with a negative exponent of 6. The radio spectra show drifting radio structures with emission in a relatively narrow (Δf ≤ 200 MHz) frequency range indicating injection of energetic electrons into a plasmoid which is slowly drifting upwards in the corona. 相似文献
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Zhongxian Shi Qijun Fu Renyang Zhao Zhengzhi Wang Jingxiu Wang Fei Wu 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(11):229-232
A bright mass ejection appearing as a spray on the disk, associated with a 3b flare has been observed. A gap with a length of 2.5 × 104 km and a width of 2 × 104 km occurred between the flare and spray was observed. The intensity of the gap is about 1.6 times more intense than the undisturbed region. The spectral properties of the radio bursts corresponding to the flare and the spray are different. In addition, the flare and the spray are also different in their hard X ray emissions.Observation has not shown any relation between teh spray and the filament that existed previously in the active region. Perhaps the flare and the spray are produced simultaneously by the same mechanism. An observational model of the flare and the spray is shown in figure 3. 相似文献
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本文提出ⅣmA型爆发的一种模型,并且以l波与s波通过非线性相互作用转化为t波的过程l±st作为其辐射机制,对8个ⅣmA型爆发计算了辐射亮温度的谱,得到一些与观测符合较好的结果。本文提出的模型和辐射机制克服了原有的模型和回旋同步辐射机制的困难,比较合理地解释了ⅣmA型爆发的主要特征。本文还就Te=Ti和Te>>Ti两种条件下的等离子体辐射机制进行了讨论。 相似文献
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George A. Dulk Donald B. Melrose 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(11):185
First recognized by Wu and Lee (Ap. J. 230, 621, 1979), electron-cyclotron masers can be activated under very mild conditions. Large growth rates can occur even for relatively mild anisotropies in the electron velocity distribution, e.g., the one-sided loss cones that commonly occur when electrons with small pitch angles precipitate into high density regions at the footpoints of flaring loops while others are reflected in the converging field in the corona. Maser action can plausibly occur at the second harmonic of the local gyrofrequency and so explain certain very bright (? 1010 K) microwave bursts from the sun and other stars. However, the preponderance of the energy is at the first harmonic.We suggest that masers operating at the local gyrofrequency in a flaring loop generate radiation at decimeter wavelengths that is a significant fraction of the total energy of the flare, in fact (and not coincidentally) comparable with the energy in electrons associated with hard X-ray bursts. Essentially all of the radio energy is trapped in the corona and serves to produce localized heating in a volume large compared with the energy release region. Thus it can transfer energy by radiation from one magnetic loop to another, possibly inducing further instabilities, and spreading the course of the flare. Eventually the energy probably escapes the corona as soft X-rays. The electron-cyclotron maser saturates by extracting the perpendicular energy of the electrons, thereby diffusing them into the loss cone at the maximum possible rate; the enhanced precipitation into the footpoints can produce bright emission in hard X-rays, EUV and Hα and remove any necessity for directive acceleration in the energy release region.Details of the proposed mechanism and effects are contained in two papers by Melrose and Dulk (Ap. J. 259, 1982).This work was sponsored by NASA under grants NAGW-91 and NSG-7287 to the University of Colorado. 相似文献
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CME在产生和发展过程中与日冕和行星际介质相互作用并发出不同波长的射电辐射.在研究了无CME时空间等离子体的各种辐射机制基础上,统计分析了1999年2月至1999年8月期间有较大的CME发生情况下,在CME影响下L1拉格朗日点附近等离子体参数发生变化后的射电辐射机制.分析结果表明,其射电辐射机制主要是轫致辐射、微量的回旋辐射和更加微弱的复合辐射.此外,分析讨论了1999年2月至1999年8月期间与CME共生的太阳微波爆发.分析结果表明,与CME共生的是微波逐渐型爆发、尖峰爆发,其辐射机制主要是轫致辐射、回旋共振辐射、等离子体辐射及电子回旋脉泽辐射. 相似文献
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L van Driel-Gesztelyi P.K Manoharan M Pick P.P Démoulin 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1997,19(12):1883-1886
Yohkoh X-ray images, multifrequency two-dimentional observations of the Nancay Radioheliograph, Kitt Peak and Mees magnetograms provide a unique set of data with which to study a C4.7 long-duration flare that was observed close to the equator (S07, W11) on 25 Oct. 1994 at 09:49 UT. Linear force-free field extrapolations indicate a very high degree of non-potentiality in the active region. The X-ray flare started with the expansion of spectacular twisted loops. Fifteen minutes after the flare onset sporadic radio (type III) bursts were observed spreading over an area of almost 1/3 of the solar disc and two remote X-ray brightenings appeared over quiet regions of opposite magnetic polarity located in on opposite hemispheres of the Sun. In the close vicinity of these remote brightenings two coronal holes formed. The timing and location of these events combined with the overall magnetic configuration provide evidence for a large-scale magnetic reconnection occurring between the expanding twisted loops and the overlying huge loops which inter-connect quiet solar regions. 相似文献
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《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1986,6(1):385-388
April 1978 was an unusually active month with five well-defined kilometric type II radio bursts observed by the radio astronomy experiment on the Voyager spacecraft. An analysis has been made of these kilometric radio events and their associated interplanetary shocks. The apparent speed of each of the shocks was determined from the average frequency drift rate of the kilometric type II burst by employing the hypothesis that the radiation was emitted at the local plasma frequency. This analysis suggests that the Type II radiation is plasma emission at the fundamental with the most intense Type II emission emanating from local dense structures in the interplanetary medium. We further show that sudden changes in the frequency drift rate can be explained by assuming that the shock propagates into a region with a different density gradient. 相似文献