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arXiv 1005.3453astro-ph.SR
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EIS和SUMER观测的极冕洞加速波

Accelerating waves in polar coronal holes as seen by EIS and SUMER

G. R. Gupta, D. Banerjee, L. Teriaca, S. Imada, S. Solanki

摘要:

我们目前的EIS/Hinode & SUMER/SOHO联合观测,允许第一次光谱检测加速扰动记录在极冕洞羽间和羽区的日冕线。从时间-距离辐射图中,我们探测到在极地羽流间区域存在传播扰动,其周期为15至20分钟,传播速度从临边上方的130+/-14 km/s增加到临边上方160”附近的330+/-140 km/s。这些扰动也可以被追踪到起源于冕洞盘上部分的明亮区域,在那里的传播速度被发现在25+/-1.3至38+/-4.5 km/s的范围内,具有相同的周期性。这些盘上的明亮区域可以被视为日冕漏斗的底部。邻近的羽流区域也显示存在传播扰动,其周期范围相同,但传播速度仅在135+/-18至165+/-43 km/s范围内。据我们所知,这一结果提供了第一个光谱证据的加速传播的扰动在极地地区接近太阳(1.2太阳半径内)。我们认为,波可能是阿尔夫文或快速磁声在羽流间和慢磁声在羽流地区。这可能导致的结论是,羽流间是加速快速太阳风的首选通道。

英文摘要:

We present EIS/Hinode & SUMER/SoHO joint observations allowing the first spectroscopic detection of accelerating disturbances as recorded with coronal lines in inter-plume and plume regions of a polar coronal hole. From time-distance radiance maps, we detect the presence of propagating disturbances in a polar inter-plume region with a period of 15 to 20 min and a propagation speed increasing from 130+/-14 km/s just above the limb, to 330+/-140 km/s around 160" above the limb. These disturbances can also be traced to originate from a bright region of the on-disk part of the coronal hole where the propagation speed was found to be in the range of 25+/-1.3 to 38+/-4.5 km/s, with the same periodicity. These on-disk bright regions can be visualized as the base of the coronal funnels. The adjacent plume region also shows the presence of propagating disturbance with the same range of period but with propagation speeds in the range of 135+/-18 to 165+/-43 km/s only. To our knowledge, this result provides first spectroscopic evidence of acceleration of propagating disturbances in the polar region close to the Sun (within 1.2 solar radii). We suggest that the waves are likely either Alfv'enic or fast magnetoacoustic in the inter-plume and slow magnetoacoustic in plume regions. This may lead to the conclusion that inter-plumes are preferred channel for the acceleration of the fast solar wind.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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