LONG-TERM PERSISTENCE OF SOLAR-ACTIVITY

We examine the question of whether or not the non-periodic variations in solar activity are caused by a white-noise, random process. The Hur st exponent, which characterizes the persistence of a time series, is evaluated for the series of C-14 data for the time interval from about 6000 BC to 1950 AD. We find a constant Hurst exponent, suggesting tha t solar activity in the frequency range from 100 to 3000 years include s an important continuum component in addition to the well-known perio dic variations. The value we calculate, H almost-equal-to 0.8, is sign ificantly larger than the value of 0.5 that would correspond to variat ions produced by a white-noise process. This value is in good agreemen t with the results for the monthly sunspot data reported elsewhere, in dicating that the physics that produces the continuum is a correlated random process and that it is the same type of process over a wide ran ge of time interval lengths.