Revivals of a coronal arch
Revivals of a coronal arch
复制标题
冠状弓的复兴
DOI：
10.1007/bf00154819
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发表时间：
1984
期刊：
影响因子：
2.8
通讯作者：
Z. Svestka
中科院分区：
文献类型：
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作者：
Z. Svestka
1980年11月6日巨大的耀斑后拱门在形成11小时和25小时后又恢复了活力。这两次爆发都是由双带耀斑和不断增长的环路系统引起的。拱门的前两次亮化是类似的事件，亮度极大值以相当恒定的速度向上穿过日冕；在所有三次亮化过程中，拱门都呈现出由两个分量组成的速度图：慢的(8-12公里−1)和快的(∼35公里S−1)，其来源未知。在第一次复兴时，在100000公里的高度，拱门的温度在亮化开始后3.5h达到峰值∼1小时，亮度∼2小时，发射测量∼3.5h。因此，拱门看起来像一个放大的耀斑，尺度在大小和时间上都增加了一个数量级。在∼海拔100000公里处，最高温度为≃14×106K，最高≃为2.5×109 cm−3。能量密度≃11.2erg cm−3.整个拱形的体积为1.1×1030cm3，总能量≃为1.2×1031erg，总质量为4.4×1015g。随着海拔的升高，密度逐渐降低，在拱顶内的任何位置都保持在7×109 cm−3以下。拱门通过辐射冷却非常缓慢，而传导冷却受到抑制。复活的拱形在原有拱形的整个范围内受到能量输入，而热扰动(新的拱形？)从下面缓慢地传播。我们认为，恢复的拱门的第一次加热是由于一些膨胀的耀斑环与旧的原有拱门的磁场重新连接。“后”耀斑环路系统的形成被推迟，并在大约30-40分钟后开始。从那时起，一个新的拱形开始在环的上方形成，我们发现的速度反映了这种形成。
The giant post-flare arch of 6 November 1980 revived 11 hr and 25 hr after its formation. Both these revivals were caused by two-ribbon flares with growing systems of loops. The first two brightenings of the arch were homologous events with brightness maxima moving upwards through the corona with rather constant speed; during all three brightenings the arch showed a velocity pattern with two components: a slow one (8–12 km−1), related to the moving maxima of brightness, and a fast one (∼ 35 km s−1), the source of which is unknown.During the first revival, at an altitude of 100000 km, temperature in the arch peaked ∼ 1 hr, brightness ∼ 2 hr, and emission measure ∼ 3.5 hr after the onset of the brightening. Thus the arch looks like a magnified flare, with the scales both in size and time increased by an order of magnitude. At ∼ 100000 km altitude the maximum temperature was ≃14 × 106K, max.ne≃ 2.5 × 109cm−3, and max. energy density ≃ 11.2 erg cm−3. The volume of the whole arch can be estimated to 1.1 × 1030 cm3, total energy ≃1.2 × 1031 erg, and total mass ≃4.4 × 1015g. The density decreased with the increasing altitude and remained below 7 × 109 cm−3 anywhere in the arch. The arch cooled very slowly through radiation whereas conductive cooling was inhibited. Since its onset the revived arch was subject to energy input within the whole extent of the preexisting arch while a thermal disturbance (a new arch?) propagated slowly from below.We suggest that the first heating of the revived arch was due to reconnection of some of the distended flare loops with the magnetic field of the old preexisting arch. The formation of the ‘post’-flare loop system was delayed and started only some 30–40 min later. Since that time a new arch began to be formed above the loops and the velocities we found reflect this formation.