The Solar Dynamo and Its Phase Transitions during the Last Millennium
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- Duhau, S. & de Jager, C. Sol Phys (2008) 250: 1. doi:10.1007/s11207-008-9212-x
We analyze the variation of the solar-dynamo magnetic-field components during the last millennium through a study of their proxy data. We introduce a phase diagram with as abscissa and ordinate the proxies of the values of the toroidal and poloidal magnetic field components. In this diagram the dynamo system appears to regularly cross a well-defined point, which we call the Transition Point. Such crossings occurred five times during the past millennium. Each of these crossings preceded a Grand Episode, either a Minimum or a Maximum one. In addition to these two types of quasiperiodic behavior, a third type consisting of weaker quasiregular oscillations (R) around the Transition Point’s coordinates is identified. These periods appear to last one or two times the Gleissberg cycle length. Between the various types of episodes there are brief phase transitions. We identify two types of such phase transitions.