Study of a filament with a circularly polarized beam at 3.8 cm
Study of a filament with a circularly polarized beam at 3.8 cm
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3.8 cm 圆偏振光束灯丝的研究
DOI：
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发表时间：
1975
期刊：
影响因子：
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通讯作者：
J. Kogut
中科院分区：
文献类型：
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作者：
R. Straka;M. Papagiannis;J. Kogut
利用120英尺的Haystack天线对左右圆极化辐射进行了广泛的观测，该天线在3.8厘米处的HPBW为4.4′。在1974年9月22日至26日这段非常平静的时期，在太阳南半球观测到两个区域，亮度温度比周围的太阳盘温度低约10%。Hα照片表明，主区与一条长的暗丝相连。射电低压中心和暗条之间的距离随着暗条向临边的推进而增加，当暗条距离太阳盘面中心的径向距离>0.8 r/min时，低压最终消失。这些观察结果与细丝模型相一致，该模型由一个薄的、高的和非常长的密度增强的薄片组成，该薄片被囚禁在一个大的和同样长的隧道状的低密度腔中。在3.8厘米发射水平，它发生在过渡区的正下方的电子密度估计是低于一个因素的空腔内比外面。另一个低气压的起源仍然不清楚，因为没有发现与任何Hα或磁性特征的关系。由于没有相关的EUV或X射线数据，无法确定与冕洞的可能联系。在未来的观测中，如果次级低压通常与长暗条上的初级低压区相关联，那么研究这一点将是有意义的。
Extensive observations of left and right circularly polarized emission were carried out with the 120 ft Haystack antenna, which at 3.8 cm has a HPBW of 4.4′. During a very quiet period, September 22–26, 1974, two regions were observed in the southern hemisphere of the Sun with brightness temperatures approximately 10% below the surrounding solar disk temperature. Hα photographs show that the main region was associated with a long filament. The separation between the center of the radio depression and the filament increased as the filament advanced toward the limb, with the depression finally disappearing when the filament was at a radial distance >0.8 r⊙ from the center of the solar disk. These observations are in agreement with a filament model consisting of a thin, tall and exceedingly long sheet of enhanced density encaged in a large and equally long tunnel-like cavity of lower density. The electron density at the 3.8 cm emission level which occurs immediately below the transition zone was estimated to be lower inside the cavity than outside by a factor of 2. The origin of the other depression remains unclear because no relation to any Hα or magnetic feature could be found. A possible association with a coronal hole could not be established because no pertinent EUV or X-ray data were available. It would be of interest to investigate in future observations if a secondary depression is normally associated with the primary depression region over a long filament.