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arXiv 2410.23928astro-ph.SR
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低阶模在太阳磁活动第23和24周的地震学差异

Seismic differences between solar magnetic cycles 23 and 24 for low-degree modes

Rafael A. Garcia, Sylvain N. Breton, David Salabert, Sushant C. Tripathy, Kiran Jain, Savita Mathur, Eva Panetier

AI总结:

本文利用GOLF、BiSON和GONG的观测数据,通过三个频段低阶模频移演化研究太阳磁活动第23和24周,发现磁场变化可能发生在表面附近,且第24周最大频移在中高纬度出现更早、赤道附近幅度更强等差异。

摘要:

太阳磁活动遵循约11年的规律周期,每22年发生一次两极极性反转。这种变化的表面磁性会影响声波模的特性,而声波模的频移是磁活动周期的良好代理指标。在本文中,我们通过三个频段内低阶模(l=0、1和2)频移的演化,研究了太阳磁活动第23和24周。这些频段探测的是太阳表面以下74至1575公里之间的特性。分析使用了来自空间仪器Global Oscillations at Low Frequency(GOLF,低频全球振荡仪)以及地面观测网络Birmingham Solar Oscillations Network(BiSON,伯明翰太阳振荡网络)和Global Oscillation Network Group(GONG,全球振荡网络组)的观测数据。径向模的频移表明,磁场振幅和结构的变化可能发生在太阳表面附近而非核心附近。第24太阳活动周的最大频移在中高纬度(相对于赤道)出现得更早,且位于光球层以下约1550公里处。在该深度但靠近赤道的区域,这一最大值与表面活动一致,但幅度更强。在约74公里深处,赤道附近的行为与表面行为相似,而在更高纬度,其强度与第23周相当。

英文摘要:

Solar magnetic activity follows regular cycles of about 11 years with an inversion of polarity in the poles every 22 years. This changing surface magnetism impacts the properties of the acoustic modes. The acoustic mode frequency shifts are a good proxy of the magnetic cycle. In this Letter we investigate solar magnetic activity cycles 23 and 24 through the evolution of the frequency shifts of low-degree modes (l= 0, 1, and 2) in three frequency bands. These bands probe properties between 74 and 1575 km beneath the surface. The analysis was carried out using observations from the space instrument Global Oscillations at Low Frequency and the ground-based Birmingham Solar Oscillations Network and Global Oscillation Network Group. The frequency shifts of radial modes suggest that changes in the magnetic field amplitude and configuration likely occur near the Sun's surface rather than near its core. The maximum shifts of solar cycle 24 occurred earlier at mid and high latitudes (relative to the equator) and about 1550 km beneath the photosphere. At this depth but near the equator, this maximum aligns with the surface activity but has a stronger magnitude. At around 74 km deep, the behaviour near the equator mirrors the behaviour at the surface, while at higher latitudes, it matches the strength of cycle 23.

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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