Action conservation in the solar cycle

Summary form only given. By simple arguments, we obtain a reduced time series for the sunspot activity. This time series can be argued to represent, approximately, the magnetic flux density at the coronal surface. The reduced sunspot index correctly reproduces also the 22-year solar cycle. Closer scrutiny of the sunspot variation shows that the local frequency of the solar cycle and the energy in the solar magnetic field vary consistently with conservation of action, i.e. local energy divided by local frequency. The analysis is based on the available data for the annual average of the sunspot number, beginning with the year 1700, and analyzed by means of a wavelet transform. The basic results are confirmed also by including other datasets. The observations regarding the action conservation can support an interpretation of the 22-year solar cycle proposed earlier by Gurnett and D´Angelo.