Solar Rotation Rate During the Cycle 24 Minimum in Activity

Abstract

The minimum of solar cycle 24 is significantly different from most other minima in terms of its duration as well as its abnormally low levels of activity. Using available helioseismic data that cover epochs from the minimum of cycle 23 to now, we study the differences in the nature of the solar rotation between the minima of cycles 23 and 24. We find that there are significant differences between the rotation rates during the two minima. There are differences in the zonal-flow pattern too. We find that the band of fast rotating region close to the equator bifurcated around 2005 and recombined by 2008. This behavior is different from that during the cycle 23 minimum. By auto-correlating the zonal-flow pattern with a time shift, we find that in terms of solar dynamics, solar cycle 23 lasted for a period of 11.7 years, consistent with the result of Howe et al. (2009). The autocorrelation coefficient also confirms that the zonal-flow pattern penetrates through the convection zone.

Accepted for publication in ApJ

References in corpus (7)

• The Solar Cycle
• Flux-transport dynamos with Lorentz force feedback on differential rotation and meridional flow: Saturation mechanism and torsional oscillations
• A note on the torsional oscillation at solar minimum
• Solar rotation rate and its gradients during cycle 23
• The onset of solar cycle 24: What global acoustic modes are telling us
• Is the current lack of solar activity only skin deep?
• Zonal Velocity Bands and the Solar Activity Cycle

Cited by in corpus (13)

• Global Seismology of the Sun
• Thinning of the Sun's magnetic layer: the peculiar solar minimum could have been predicted
• Revisiting the solar tachocline: Average properties and temporal variations
• Mass Loss via Solar Wind and Coronal Mass Ejections During Solar Cycle 23 and 24
• Rotation rates of the coronal holes and their probable anchoring depths
• Changes in the solar rotation over two solar cycles
• A Helioseismic Perspective on the Depth of the Minimum Between Solar Cycles 23 and 24
• Changes in the near-surface shear layer of the Sun
• A Comparison of Solar Cycle Variations in the Equatorial Rotation Rates of the Sun's Subsurface, Surface, Corona, and Sunspot Groups
• On the magnetic field required for driving the observed angular-velocity variations in the solar convection zone
• Differential Rotation in Convective Envelopes: Constraints from Eclipsing Binaries
• Solar-cycle variations in meridional flows and rotational shear within the Sun's near-surface shear layer
• Seismology of the Sun : Inference of Thermal, Dynamic and Magnetic Field Structures of the Interior