Part II Current stellar dynamo theory

The Sun and Cool Stars: activity, magnetism, dynamos

Volume 380 of the series Lecture Notes in Physics pp 117-128


Waves of Solar Activity

  • M. R. E. ProctorAffiliated withDepartment of Applied Mathematics and Theoretical Physics, University of Cambridge
  • , E. A. SpiegelAffiliated withDepartment of Astronomy, Columbia University

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We develop a theory of the sunspot cycle predicated on the assumption that the observed bands of activity are packets of dynamo waves. An approximate equation is proposed to describe the dynamics of these packets, using standard ideas from bifurcation theory. We show that in a certain limit the system can be described in terms of a slowlyevolving solitary wave, and that periodic behavior, like that of the observed butterfly diagram, can easily be found. Generalizations of the theory are discussed.