Periodicity of the Solar Full-Disk Magnetic Fields

Xiang, N. B.; Qu, Zhining; Zhai, Qingfeng

doi:10.1088/0004-6256/148/1/12

Cited by 43 publications

(11 citation statements)

References 23 publications

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“…The reason is that the relatively early MWSI should be one source of the relatively late MPSI . Consequently, the phase relationship among TSI, MPSI, and MWSI in our study should coincide with Xiang et al (2014), and it should indirectly validate that the MPSI components partly come from relatively early MWSI measurements. Spruit (1991) indicated that the solar convective envelope likes a "thermal superconductor" with a huge thermal inertia, and the same thermal inertia makes possible the irradiance fluctuations due to "superficial" photospheric magnetic structures.…”

Section: Conclusion and Discussionsupporting

confidence: 61%

“…The MWSI values are also calculated in much the same manner as the MPSI, but summation is only done for pixels where the absolute value of the magnetic field strength is greater than 100 G (Howard et al 1980(Howard et al , 1983Ulrich 1991;Ulrich et al 1991;Li et al 2014;Xiang et al 2014). The MPSI and MWSI should represent the activity of weak magnetic field (with plage/ facular regions and outside of sunspots) on the solar full disk and the strong magnetic field activity (in sunspots) on the disk, respectively (Chapman & Boyden 1986;Parker et al 1998;Li et al 2014;Xiang et al 2014). The two indices can be downloaded from MWO (http://obs.astro.ucla.edu/ intro.html).…”

Section: Datamentioning

confidence: 99%

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What Causes the Inter-Solar-Cycle Variation of Total Solar Irradiance?

Xiang

Kong

2015

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The Physikalisch Meteorologisches Observatorium Davos total solar irradiance (TSI), Active Cavity Radiometer Irradiance Monitoring TSI, and Royal Meteorological Institute of Belgium TSI are three typical TSI composites. Magnetic Plage Strength Index (MPSI) and Mount Wilson Sunspot Index (MWSI) should indicate the weak and strong magnetic field activity on the solar full disk, respectively. Cross-correlation (CC) analysis of MWSI with three TSI composites shows that TSI should be weakly correlated with MWSI, and not be in phase with MWSI at timescales of solar cycles. The wavelet coherence (WTC) and partial wavelet coherence (PWC) of TSI with MWSI indicate that the inter-solar-cycle variation of TSI is also not related to solar strong magnetic field activity, which is represented by MWSI. However, CC analysis of MPSI with three TSI composites indicates that TSI should be moderately correlated and accurately in phase with MPSI at timescales of solar cycles, and that the statisticalsignificancetest indicates that the correlation coefficient of three TSI composites with MPSI is statistically significantly higher than that of three TSI composites with MWSI. Furthermore, the cross wavelet transform (XWT) and WTC of TSI with MPSI show that the TSI is highly related and actually in phase with MPSI at a timescale of a solar cycle as well. Consequently, the CC analysis, XWT, and WTC indicate that the solar weak magnetic activity on the full disk, which is represented by MPSI, dominates the inter-solar-cycle variation of TSI.

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Section: Conclusion and Discussionsupporting

confidence: 61%

Section: Datamentioning

confidence: 99%

What Causes the Inter-Solar-Cycle Variation of Total Solar Irradiance?

Xiang

Kong

2015

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“…Solar rotation is one of the essential properties of the Sun as a star, but it is still to be understood clearly from the existing large volumes of observational data (Schroeter 1985;Beck 2000;Xiang et al 2014). Generally speaking, traditional measurements of solar differential rotation in the surface atmospheric layers could be carried out mainly by using three methods: magnetic tracers, spectroscopic observations, and flux modulations (Gilman 1974;Howard 1984;Vats et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Systematic regularity of solar coronal rotation during the time interval 1939–2019

Deng

Zhang

Deng

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Temporal variation of the solar coronal rotation appears to be very complex and its relevances to the eleven-year solar activity cycle are still unclear. Using the modified coronal index for the time interval from 1939 January 1 to 2019 May 31, the systematic regularities of the solar coronal rotation are investigated. Our main findings are as follows: (1) from a global point of view, the synodic coronal rotation period with a value of 27.5 days is the only significant period at the periodic scales shorter than 64 days; (2) the coronal rotation period exhibit an obviously decreasing trend during the considered time interval, implying the solar corona accelerates its global rotation rate in the long run; (3) there exist significant periods of 3.25, 6.13, 9.53, and 11.13 years in the period length of the coronal rotation, providing an evidence that the coronal rotation should be connected with the quasi-biennial oscillation, the eleven-year solar cycle, and the 22-year Hale cycle (or the magnetic activity reversal); and (4) the phase relationship between the coronal rotation period and the solar magnetic activity is not only time-dependent but also frequency-dependent. For a small range around the 11-year cycle band, there is a systematic trend in the phase, and the small mismatch in this band brings out the phase to drift. The possible mechanism for the above analysis results is discussed.

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“…MWSI is calculated similarly, but for pixels whose absolute values are greater than 100 Gauss 5 . MWSI should thus represent large-scale magnetic field activity mainly in sunspot regions at the solar full disk, while MPSI represents small-scale magnetic field activity outside sunspot regions (Xiang et al 2014; Xiang & Qu 2016). Figure 5 shows MPSI and MWSI from 1970 Jan 19 to 2012 Dec 31.…”

Section: Phase Relationship Of Long-term Solar Activitiesmentioning

confidence: 99%

Investigation of the coronal heating through phase relation of solar activity indexes

Yin

et al. 2020

Publ. Astron. Soc. Aust.

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The coronal heating problem is a long-standing perplexing issue. In this study, 13 solar activity indexes are used to investigate their phase relation with the sunspot number (SSN). Only three of them are found to statistically significantly lag the SSN (large-scale magnetic activity) by about one solar rotation period; the three indexes are total solar irradiance (TSI), the modified coronal index, and the solar wind velocity; the former two indexes may represent the long-term variation of energy quantity of the heated photosphere and corona, respectively. The Mount Wilson Sunspot Index (MWSI) and the Magnetic Plage Strength Index (MPSI), which reflect the large- and small-scale magnetic field activities, respectively, are also utilised to investigate their phase relations with the three indexes. The three indexes are found to be much more intimately related to MPSI than to MWSI, and MWSI statistically significantly leads TSI by about one rotation period. The heated corona is found to pulse perfectly in step with the small-scale magnetic activity rather than the large-scale magnetic activity; furthermore, combined with observations, our statistical evidence should thus attribute coronal heating firmly to small-scale magnetic activity phenomena, such as spicules, micro-flares, nano-flares, and others. The photosphere and the corona are synchronously heated, which should seemingly prefer magnetic reconnection heating to wave heating. In the long term, such a coronal heating way is inferred effective. Statistically, it is also small-scale magnetic activity phenomena that produce TSI enhancement. Coronal heating and solar wind acceleration are found to be synchronous, as standard models require.

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Periodicity of the Solar Full-Disk Magnetic Fields

Cited by 43 publications

References 23 publications

What Causes the Inter-Solar-Cycle Variation of Total Solar Irradiance?

What Causes the Inter-Solar-Cycle Variation of Total Solar Irradiance?

Systematic regularity of solar coronal rotation during the time interval 1939–2019

Investigation of the coronal heating through phase relation of solar activity indexes

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