Periodicities in the coronal rotation and sunspot numbers

Abstract

The present study is an attempt to investigate the long term variations in coronal rotation by analyzing the time series of the solar radio emission data at 2.8 GHz frequency for the period 1947 - 2009. Here, daily adjusted radio flux (known as Penticton flux) data are used. The autocorrelation analysis shows that the rotation period varies between 19.0 to 29.5 sidereal days (mean sidereal rotation period is 24.3 days). This variation in the coronal rotation period shows evidence of two components in the variation; (1) 22-years component which may be related to the solar magnetic field reversal cycle or Hale's cycle, and (3) a component which is irregular in nature, but dominates over the other components. The crosscorrelation analysis between the annual average sunspots number and the coronal rotation period also shows evidence of its correlation with the 22-years Hale's cycle. The 22-years component is found to be almost in phase with the corresponding periodicities in the variation of the sunspots number.

9 pages, 5 figures, Accepted for publication in MNRAS

References in corpus (3)

• Differential rotation measurement of soft X-Ray corona
• Differential coronal rotation using radio images at 17 GHz
• Comparison of the sidereal angular velocity of subphotospheric layers and small bright coronal structures during the declining phase of solar cycle 23

Cited by in corpus (9)

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• On Midrange Periodicities in Solar Radio Flux and Sunspot Areas
• On the Rotation of the Solar Chromosphere
• Internal-cycle variation of solar differential rotation
• Evidence of strong relationship between hemispheric asymmetry in solar coronal rotation and solar activity during solar cycle 24
• Evolution of solar wind sources and coronal rotation driven by the cyclic variation of the Sun's large-scale magnetic field
• Study on the Temporal Evolution of the Radial Differential Rotation of Solar Corona Using Radio Emissions