We show that the axisymmetric odd degree SHF modes of 21.4-yr periodicity and degrees l < 29 in the solar magnetic field (as inferred from sunspot data during , are at least approximately stationary. Among the sine and cosine components of these SHF modes we find four groups, each defining the geometry of a coherent global oscillation characterized by a distinct power hump and its own level of variation. The first two of these 'geometrical eigenmodes' (viz., B 1 and B2), define the large-scale structure &the butterfly diagrams. Remaining SHF modes define the orderliness of the field distribution even within the 'wings' of the 'butterflies' down to scales l ~ 29. These include the 'geometrical eigenmodes' B 3 and B4, which are not present in simulated data sets in which the latitudes of the sunspot groups are randomly redistributed within the 'wings' of the 'butterflies'.
Superposition of B i, B2, B3, and B 4 is necessary and sufficient to reproduce important observed properties of the latitude-time distribution of the real field, not only in the 'sunspot zone', but also in the middle (35 ~ ~ and the high (> 75 ~ latitudes, with appropriate relative orders of magnitude and phases. Thus, B~, B2, B3, and B 4 seem to represent really existing global oscillations in the Sun's internal magnetic field. The geometrical form of Bj may also be the form of the 'forcing' oscillation.