Discreteness of rotation periods of solar and interplanetary magnetic fields

The rotation of the solar magnetic fields has been investigated using the polarity of the interplanetary magnetic field (IMF, 1954-1980) and the measurements of the mean magnetic field of the Sun seen as a star (SMMF, 1968-1980). Each data set was treated as single time series. The power spectra of these two different physical fields reveal the set of discrete peaks centered on the well known 27-28-day period of solar rotation. The most significant peaks, in particular those at 26.30, 27.40, 27.82, 28.16 and 28.46-day perio26.96ds, are well reproduced in both, of SMMF and IMF, spectra and testify to certain heliolatitudes for the appearance of the recurrent periods in the solar and interplanetary magnetic fields. The longest, yet significant, periods near 30 days as observed in the SMMF and IMF data sets indicate that solar magnetic fields originating at high latitudes, 40 to 50 deg, are still appreciably contribute to the SMMF measured by solar magnetograph and to the IMF observed at the Earth orbit. Several short-period peaks seen in the power spectra might be a reflection of some magnetic structures rapidly rotating near equator with synodic periods of about 25.4 to 26.4 days