Normalised periods of magneto-Rossby wave spherical harmonics vs dynamo magnetic field strength for the solar dynamo layer. Curves with different colours correspond to the harmonic with m = 1 and l = 4, 5, 6, 7, respectively. The harmonics with m = 1 and l = 4, 5, 7, correspond to the observed periods in the case of solar dynamo field strength of 10 kG. Note that no clear detection is seen for the m = 1, l = 6 harmonic.