Published online by Cambridge University Press: 12 April 2016
We suggest a mechanism of energy transmission from stellar radial pulsations into torsional oscillations in a dipole-like magnetic field. We show that the stellar radial pulsations cause a periodical variation of the Alfén speed which leads to the Mathieu equation for torsional Alfén waves. Harmonics with half the frequency of the pulsations have exponentially growing amplitudes. Then the energy supporting the various type of pulsations can be transformed into purely electromagnetic oscillations of the star.