Solar Activity in the Last 20 Years and a Forecast of the 25th Solar Cycle

Experimental data on solar activity (sunspot number, induction of solar polar magnetic field B_p, and others), characteristics of interplanetary space, and cosmic ray fluxes testify that the Sun has entered a deep minimum of its activity similar to the Dalton minimum. An almost functional relationship was found between maximum values of B_pmax observed in the solar activity minimum of the 11-year cycle and the next sunspot maximum. Based on this relationship, a simple method of forecasting maximum number of sunspots R_zmax and time course R_z(t) was developed. A forecast of the 25th solar cycle is given.