arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.13204astro-ph.SRphysics.space-ph
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太阳活动23周和24周期间CME膨胀速度的比较

A comparison of CME expansion speeds between solar cycles 23 and 24

Fithanegest Kassa Dagnew, Nat Gopalswamy, Solomon Belay Tessema

摘要:

我们报告了第23和24太阳活动周之间的边缘日冕物质抛射(CME)的膨胀速度的比较。我们从两个周期中选择了大量与软X射线耀斑大小大于或等于M1.0相关的肢体CME事件。我们使用了在线CME目录(https://www.example.com)中提供的数据和测量工具,该目录包括太阳和日光层天文台(SOHO)大角度和光谱日冕仪(LASCO)检测到的所有CME的属性。我们发现,在第24个循环中的膨胀速度高于在第23个循环中的膨胀速度。我们还发现,径向和膨胀速度之间的关系有不同的斜率在第23和24周期。第24周期的斜率比第23周期的斜率高45%。对于给定的径向速度,膨胀速度也更高。差异随着速度而增加。对于2000 km/s的径向速度,第24周期的膨胀速度高出约48%。这些结果为第24周期日冕物质抛射的异常膨胀提供了额外的证据,这是由于日球层总压降低造成的。

英文摘要:

We report on a comparison of the expansion speeds of limb coronal mass ejections (CMEs) between solar cycles 23 and 24. We selected a large number of limb CME events associated with soft X-ray flare size greater than or equal to M1.0 from both cycles. We used data and measurement tools available at the online CME catalog (https://cdaw.gsfc.nasa.gov) that consists of the properties of all CMEs detected by the Solar and Heliospheric Observatory's (SOHO) Large Angle and Spectrometric Coronagraph (LASCO). We found that the expansion speeds in cycle 24 are higher than those in cycle 23. We also found that the relation between radial and expansion speeds has different slopes in cycles 23 and 24. The cycle 24 slope is 45% higher than that in cycle 23. The expansion speed is also higher for a given radial speed. The difference increases with speed. For a 2000 km/s radial speed, the expansion speed in cycle 24 is ~48% higher. These results present additional evidence for the anomalous expansion of cycle 24-CMEs, which is due to the reduced total pressure in the heliosphere.

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