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本文给出了1981年4月27日发生在太阳西边缘一个黑子群(Boulder编号3049)上空的耀斑环珥的上升运动特征和某些初步结果。 研究结果表明,该耀斑状环形日珥的运动特征和状态跟它亮度变化关系甚密,亮度极大前环珥不断上升加速,其最大平均速度和加速度分别约为17.5公里/秒和0.023公里/秒~2。亮度极大后为上升减速运动。环珥顶部存在着剧烈的膨胀运动,它最大的横向膨胀速度约10.6公里/秒,膨胀速度随上升高度的增加而减小,膨胀加速和膨胀减速两阶段也以亮度极大附近为分界。 环珥顶部和两腿系有整体的视向运动,两腿系存在着同向的旋转运动,分裂成几块的南腿系按刚体模式作螺旋运动。 对该环珥耀斑跟它对应的黑子活动区的关系也作了简单讨论。(附照片见附图21) 相似文献
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本文利用完全线性化方法处理了一个日珥的光谱资料,得到其物理参数的二维分布。结果表明:在日珥中心,运动温度和中性氢密度随高度增加而减少,湍动速度随高度增加而增加;而在日珥边缘,运动温度不随高度变化。从中心到边缘,运动温度是增加的。日珥中不存在流体静力学平衡,磁场对日珥支撑起重要作用。 相似文献
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分别对1989年5月8日太阳西南边缘爆发了一个SN级的圆形耀斑部分和柱状物质抛射部分的运动情况进行分析讨论。耀斑圆形直径增大过程的膨胀速度较大，最大为110km／s，时间非常快，从开始产生至膨胀到最大直径15500km仅用了4min时间；减小收缩的过程速度缓慢，为-20～-10km／s，时间过程相对长，从最大直径开始减小到完全消失用了17min时间。柱状物质抛射部分的直径从开始膨胀到最大9060kin用了7min时间，最大速度为35kin／s；收缩过程用了14min时间，收缩速度在-15～-5km／s左右。柱状物质抛射部分的升降速度，在耀斑极大以后的时间仍在上升，并仍以很高的速度向上喷射，到耀斑极大后3min才开始下降。柱状物质抛射部分到达最大高度22000km的时间与其直径膨胀到最大的时间同时，上升的速度100～130km／s，下降的速度在-20～-5km／s，抛射物质下降到16000～15000km的高度缓慢消失。 相似文献
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用"多云模型"光谱方法分析1991年3月5日喷泉状爆发日珥的Hα光谱观测资料,导出了该日珥视向速度的二维分布;通过速度场分析,我们探测到日珥喷射速度和旋转角速度随高度的分布,结果表明该日珥的蓝移速度占绝对优势,速度变化范围为8～110km/s,速度分布不均衡、不对称,日珥中部和底部速度较大、顶部速度较小;日珥南边缘的速度梯度比北边缘的更大;日珥的喷射除表现为上升运动外还显示出向着观测者的、平均速度约为50km/s的视向运动;该日珥的旋转角速度约为7×10-4rad/s,两者随高度的变化显示出相反的特征。 相似文献
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作为文献[1]中工作的继续,本文用解析方法论证了日珥源函数随深度变化与各种速度场结合对谱线轮廓对称性的影响。得到的结论为:(1)常速度场与源函数随深度任意分布结合的谱线为对称轮廓;(2)源函数自日珥中心向前后边界线性对称增大与速度场为线性对称膨胀结合的谱线轮廓为不对称轮廓,且呈双峰结构,紫峰高于红峰;(3)源函数自日珥中心向前后边界线性增大与速度场为线性对称压缩结合的谱线轮廓是不对称的,且呈双峰结构,红峰高于紫峰;(4)源函数自日珥中心向前后边界对称减少与速度场为线性对称膨胀或线性对称压缩结合的谱线为非对称轮廓,原则上也会出现双峰结构,但可能不明显。最后,用数值计算对理论分析结果作了检验。 本文作为文[1]的继续,将用解析方法讨论源函数随深度变化对日珥谱线轮廓对称性的影响。首先讨论速度场为常数源函数随深度任意变化时谱线轮廓的对称性问题,然后讨论速度场自日珥中心对称膨胀或对称压缩与源函数自日珥中心向外边界对称增大或对称下降相结合的模型中,日珥谱线的对称性问题。 相似文献
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本文介绍了１９９１年３月５日一个与３Ｎ级光学耀斑伴生的喷泉状爆发日珥。用Ｈα线观测从开始到结束整个过程共持续约５０分钟时间，日珥的最大投影高度１５．９万公里，视向速度分布表明，日珥主要以较大的速度向着观测者的运动，最大速度每秒１２０公里。 相似文献
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1991年3月5日的喷泉状爆发日珥及视向速度分布 总被引：5，自引：3，他引：2
本文介绍了１９９１年３月５日一个与３Ｎ级光学耀斑伴生的喷泉状爆发日珥。用Ｈα线观测从开始到结束整个过程共持续约５０分钟时间，日珥的最大投影高度１５．９公公里，视向速度分布表明，日珥主要以较大的速度向着观测者的运动，最大速度每秒１２０公里。 相似文献
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１９９０年８月２９日在太阳东边缘（Ｅ９０；Ｓ１２，ＮＯＡＡ／ＵＳＡＦ６２４１）爆发了一个龙卷日珥，本文对这个龙卷日珥进行了详细的形态分析和光谱诊断，结果表明：（１）龙卷日珥有规则地螺旋运动上升，上升到最大高度后，日珥内物质无规则地纷纷下坠，这种螺旋运动可能是带电粒子漂移运动产生的电场与日珥内冻结磁场相互作用的结果；（２）龙卷日珥形态快速变化，最后呈规则的环状结构；（３）龙卷日珥的形态可能是一个重要的因素，它体现了局部区域磁场结构的变化。本文提出了一种可能的磁场结构模型，对观测结果给予了较好的解释。 相似文献
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本文对1980年10月15日产生在小黑子区的3级大耀斑作了详细的形态分析,,结果表明:1)耀斑无闪相,耀斑的最大强度为周围来扰区的2.4倍。2)耀斑有M带结构,双带的分离速度为5公里/秒。3)和耀斑有关的暗条位于大尺度磁场的极性分界线上,它在耀斑前和耀斑期间有明显变化,最终全部消失。4)耀斑的微波爆发增量小,上升下降缓慢,米波段有Ⅱ、Ⅲ、Ⅳ型爆发。5)耀斑的x射线辐射引起电离层2级骚扰(SLD)。耀斑无地磁暴对应。6)产生耀斑的活动区在日面存在3周,耀斑产生在活动区的衰亡阶段。以上结果基本与文献相同。 在本文的最后一节,对无黑子或小黑子区的耀斑形成作了简短的讨论,指出由日珥物质下落形成大耀斑所遇到的能量亏缺;日珥物质下落形成的激波,由于磁场的存在而强度削弱,磁场不能通过激波转化为辐射能;无黑子(或小黑子)区的耀斑的形成,在机理上可能与黑子区形成的耀斑类同。 相似文献
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日珥上升运动和日冕物质抛射的关系 总被引：1，自引：0，他引：1
本文基于观测日珥上升运动与日冕物质抛射（CME）之间的紧密联系和我们对日珥动力学特征的理解，探讨了在背景场作用下，日珥上升时其上方盔状冕流的动力学演化规律；分析了1980年8月18日爆发日珥与对应的CME事件之间的内在关系．结果表明：（1）缓慢上升的日珥只引起盔状冕流缓慢演化；（2）加速上升日珥的加速度和末速度的大小决定形成CME事件的激烈程度；（3）CME事件的能量可能来源于爆发日环释放的磁能．理论分析与观测结果基本一致． 相似文献
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G. W. Pneuman 《Solar physics》1984,94(2):299-313
Recent coronagraph observations of rising priminences such as in the 14 April and 5 May, 1980 coronal transient events, as well as other older observations, have shown evidence for helical structure in the prominences. If this is true, then a study of the dynamical evolution of rising helical structures in a nonuniform atmosphere is worthwhile. For this study, three important considerations become apparent: (1) Since the ends of the prominence remain rooted in the photosphere, significant stretching of the configuration will result as it rises, (2) due to the fall-off with height of the external quantities, such as gas and magnetic pressure, the prominence will experience time-varying boundary conditions as it rises, and (3) significant lateral expansion of the prominence is expected as the external conditions weaken with height. The interplay of all these effects togehter result in a quite complex dynamical behavior of the prominence.We have tried to obtain some insight into this general problem through a simple model - that of a helical pinch rising in a low beta atmosphere under the influence of an ambient external magnetic field which declines in strength with radial distance from the solar center. Under the general assumptions of an internal uniform, but time-varying, temperature and neglecting gravitational stratification within the prominence, expressions are derived for associated variations in the prominence structure as it rises. We discuss in some detail, particular quantities which are potentially most accessible to observation such as prominence radius, density, and pitch angle as they vary with height during the eruptive process.The National Center for Atmospheric Research is sponsored by the National Science Foundation. 相似文献
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Simple models for the MHD eruption of a solar prominence are presented, in which the prominence is treated as a twisted magnetic flux tube that is being repelled from the solar surface by magnetic pressure forces. The effects of different physical assumptions to deal with this magneto-hydrodynamically complex phenomenon are evaluated, such as holding constant the prominence current, radius, flux or twist or modelling the prominence as a current sheet. Including a background magnetic field allows the prominence to be in equilibrium initially with an Inverse Polarity and then to erupt due to magnetic non-equilibrium when the background magnetic field is too small or the prominence twist is too great. The electric field at the neutral point below the prominence rapidly increases to a maximum value and then declines. Including the effect of gravity also allows an equilibrium with Normal Polarity to exist. Finally, an ideal MHD solution is found which incorporates self-consistently a current sheet below the prominence and which implies that a prominence will still erupt and form a current sheet even if no reconnection occurs. When reconnection is allowed it is, therefore, driven by the eruption. 相似文献
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We have observed an eruptive prominence at the east solar limb on 25 January 1991 which started earlier than 0623 UT and was associated with a limb flare (S16 E90) of class 1B/ X10.0. We have recorded a huge mass ejection in the corona by the limb flare associated eruptive prominence. The eruptive prominence ejected a part of the loop in the corona with maximum speed of about 1280 km/sec. The ejected material attain height upto 150,000 km in the corona and finally faded/disappeared in the corona. During the ascending phase of the prominence material in the corona there was a unscrewing of the loop system associated with the eruptive prominence. The type II, III, and IV radio bursts were also reported by a number of Radio Observatories during observation of the eruptive prominence. The high flux of sudden ionospheric disturbances and the solar radio emissions on fixed frequencies (245–80000 MHz) were also recorded. The eruptive prominence associated with limb flare also shows increased proton flux (>10 MeV) during its occurence. The flare was classified as X10.0 flare. In this paper we have analysed the observed data and compared it with the theoretical model of the solar flare.On leave from his original Institute 相似文献
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Apparent motions of a number of ascending prominences of the limb-SD type (sudden disappearances) are investigated. The direction, the velocity of ascent and the correlation with flares are studied. The maximum velocity, which seems to deviate systematically from the radial direction, increases with height and shows a clear dependence on the distance to an initiating flare and its importance.A good correlation between ascending prominences and solar radio emission has been found. 相似文献
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We analyse the magnetic support of solar prominences in two-dimensional linear force-free fields. A line current is added to model a helical configuration, well suited to trap dense plasma in its bottom part. The prominence is modeled as a vertical mass-loaded current sheet in equilibrium between gravity and magnetic forces.We use a finite difference numerical technique which incorporates both vertical photospheric and horizontal prominence magnetic field measurements. The solution of this mixed boundary problem generally presents singularities at both the bottom and top of the model prominence. The removal of the singularities is achieved by superposition of solutions. Together with the line current equilibrium, these three conditions determine the amplitude of the magnetic field in the prominence, the flux below the prominence and the current intensity, for a given height of the line current. A numerical check of accuracy in the removal of singularities, is done by using known analytical solutions in the potential limit.We have investigated both bipolar and quadrupolar photospheric regions. In this mixed boundary problem the polarity of the field component orthogonal to the prominence is mainly fixed by the imposed height of the line current. For bipolar regions above (respectively below) a critical height the configuration is inverse (respectively normal). For quadrupolar regions the polarity is reversed if we refer the prominence polarity to the closest photospheric polarities. We introduce the polarity of the component parallel to the prominence axis with reference to a sheared arcade. Increasing the shear with fixed boundary conditions can increase or decrease the mass supported depending on the configuration. 相似文献
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Olga G. Badalyan 《New Astronomy》2010,15(1):135-143
The differential rotation of the solar corona has been analyzed using as the input data the brightness of the coronal green line Fe xiv 530.3 nm for more than five activity cycles. It is found that the character of rotation of the solar corona changes during the activity cycle. Approximately at the middle of the descending branch the differential rotation is weakly pronounced, while the greatest differential gradient is observed at the ascending branch and, occasionally, at the maximum of the cycle. An explanation of this difference has been suggested. The total rotation rate of the corona can be represented as a superposition of two rotation modes (components) – the fast and slow ones. The synodic period of the fast mode near the equator is about 27 days, increasing slightly with latitude. The synodic period of the slow mode exceeds 30 days. The changing relative fraction of these two modes results in variation of the latitude dependence of the observed rotation rate during the activity cycle. The characteristics of two principal types of differential rotation of the solar corona have been determined. The first type consists of the fast mode alone and is established approximately at the middle of the descending branch of the cycle. The second type is the sum of both modes with the fast mode dominating at low latitudes and the slow mode at high latitudes. The results obtained can be used for in-depth study of interaction of the velocity field and dynamo mechanism in the Sun and stars. 相似文献
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Sunspot activity is usually described by either sunspot numbers or sunspot areas. The smoothed monthly mean sunspot numbers
(SNs) and the smoothed monthly mean areas (SAs) in the time interval from November 1874 to September 2007 are used to analyze
their phase synchronization. Both the linear method (fast Fourier transform) and some nonlinear approaches (continuous wavelet
transform, cross-wavelet transform, wavelet coherence, cross-recurrence plot, and line of synchronization) are utilized to
show the phase relation between the two series. There is a high level of phase synchronization between SNs and SAs, but the
phase synchronization is detected only in their low-frequency components, corresponding to time scales of about 7 to 12 years.
Their high-frequency components show a noisy behavior with strong phase mixing. Coherent phase variables should exist only
for a frequency band with periodicities around the dominating 11-year cycle for SNs and SAs. There are some small phase differences
between them. SNs lag SAs during most of the considered time interval, and they are in general more asynchronous around the
minimum and maximum times of a cycle than at the ascending and descending phases. 相似文献
19.
The origin of the material which is ejected during a white light coronal transient has not been determined heretofore. Study of a disturbance on 26 and 27 August 1973, during which a slowly ascending prominence and a more rapid accompanying coronal transient were simultaneously observed, helps to resolve this question. Prominence images obtained in Hα 6563 Å and in He II 304 Å are nearly identical. The mass ejection transient observed in white light (3700–7000 Å) appeared to be a loop about 1 R⊙ higher than the top of the ascending prominence; it accelerated away from the prominence below it. These observations imply: (1) the bulk of the ejected material did not originate in the ascending prominence; (2) therefore, most of the material must have come from the low corona above the prominence, (and was at coronal temperatures during its outward passage); and (3) the total event - ascending prominence accompanied by coronal mass ejection - was far larger, more energetic, and longer lasting than would be inferred from the prominence observations alone. The transient of 26–27 August was slow and of atypical shape compared to other mass ejection transients, but we believe that these three conclusions apply to most, if not all, of the more than 60 loop-shaped coronal transients observed by the High Altitude Observatory's coronagraph during the nine-month flight of Skylab. 相似文献
20.
A. Peraiah 《Journal of Astrophysics and Astronomy》1980,1(1):3-16
Comoving frame calculations have been used to compute the spectral lines formed in rapidly expanding spherical media. We have
employed the angle-averaged partial frequency redistribution functionR
I with a two-level atom model in non-LTE atom approximation. A linear velocity law increasing with radius has been employed
with maximum velocity at Τ=0 being set equal to 30 mean thermal units. It is found that one obtains almost symmetric emission
line profiles at large velocities similar to those found in quasars. 相似文献