The solar magnetic flux mid-term periodicities and the solardynamo

We investigate here the fluctuations in the total, open and closed solar magnetic flux (SMF) for the period 1971-1999 by means of the maximum entropy method in the frequency range 5 x 10(-9)-10(-7) Hz (6 yr to 120 days). We use monthly data for the total, open and closed magnetic solar fluxes. Periodicities found in the series are similar showing that there is some relationship between the fluxes. The most important finding of this work is the existence of fluctuations at around 1.3 and 1.7yr in the SMF with alternating importance during consecutive even and odd solar cycles. These fluctuations are directly related with variations present in cosmic rays, solar wind parameters and geomagnetic activity indexes. A quasi-triennial periodicity previously found in sunspots and other solar phenomena is also of importance. The SMF is generated by the action of the solar dynamo; therefore, it is through the magnetic flux that the solar dynamo influences several heliospheric phenomena. (c) 2005 Elsevier Ltd. All rights reserved.