A study of the IMF fluctuation spectrum in the frequency range 10-4÷1.67•10-3 Hz during solar activity cycle development

Temporal changes in the IMF fluctuation power spectra in the frequency interval similar to 10(-4) divided by 1.67 . 10(-3) Hz are studied. The 5-min data of the IMF magnitude, obtained aboard IMP-8 for 1980-1991, are used. For the analysis the information on the low-energy cosmic ray flux (E-p > 1 MeV), the frequency of geomagnetic storms with a sudden commencement and sunspot numbers has also been attracted. It is shown that a level of small-scale (10(10) divided by 10(12) cm) turbulence of solar wind is naturally changed in the 11-year cycle of solar activity. It may be inferred that low-energy cosmic ray fluxes associated with coronal activity of the Sun can generate magnetohydrodynamic waves in the vicinity of the Earth. Evidence for the appropriate changes of the IMF spectrum index in the solar cycle has been also obtained. (C) 1999 Elsevier Science Ltd. All rights reserved.