Comparisons of Photospheric Convection Cell Characteristics During the Solar Minima of Cycles 22-23 and 23-24
Abstract
With its elongated tail and extended periods of zero activity, the period marking the transition from solar cycle 23 to 24 has seemed peculiar when compared to other minima. Among the various phenomena studied, the evolution of the solar convection zone may provide insight into the causes and consequences of this recent minimum.
Convection in the Sun plays an important role in generating and structuring the solar magnetic field and as a mechanism responsible for the 11-year solar cycle. The observed phenomena are strongly linked within both observational and physical regimes. This study uses SOHO/MDI Dopplergrams to highlight supergranulation within the line-of-sight velocity data. Suites of analysis methods are applied to time-series of Doppler images to quantitatively describe supergranule flow velocities, spatial scales and temporal lifetimes. The results show similarities in supergranule evolution (1/e lifetimes of 18 hours), while their sizes are smaller and their flows stronger during the 23-24 minimum compared to 22-23. We also present provisional results of statistical analyses performed both within and between the various data sets, some of which tend to show a quasi-oscillatory nature. Future studies to place this work in the wider context of the solar cycle are discussed, as a whole as well as investigations of supergranule characteristics found in various other data such as magnetograms and CaIIK images. Observed hemispheric asymmetries will be presented and how our methods may be applied to further these enquiries.- Publication:
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American Astronomical Society Meeting Abstracts #216
- Pub Date:
- May 2010
- Bibcode:
- 2010AAS...21631702W