Accession Number : ADA260039


Title :   Chaotic Dynamics of the Solar Cycle


Descriptive Note : Annual rept. 1 Nov 1991-30 Nov 1992


Corporate Author : COLUMBIA UNIV NEW YORK COLUMBIA ASTROPHYSICS LAB


Personal Author(s) : Spiegel, Edward A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a260039.pdf


Report Date : 30 Nov 1992


Pagination or Media Count : 7


Abstract : In modeling the solar cycle, one proceeds on the assumption that the processes driving the solar cycle are deterministic. In that case, a chaotic model is a good choice for a description of its complexity. In the modeling reported here, the authors suppose that the solar activity variation is composed of two distinct, coupled processes: one a conventionally chaotic system, and the other a nonlinear oscillator. This idea comes directly from their analysis of the observations. Since the sun's rotation period is one month, they do not use the daily sunspot number, but work with its monthly average. This quantity shows both the cyclic variation on the 11-year time scale and additional strong fluctuations. If they smooth the data to remove periods less than a year or two, they see the solar cycle clearly exposed. When they subtract this smoothed sunspot number from the monthly average, they obtain the fluctuations in the sunspot number. In figure 1, the authors show a comparison between the monthly averaged number and the fluctuations for a few cycles. There is a clear correlation between the level of solar activity as measured by the sunspot number, and the amplitude of the fluctuations in this number. They suggest that the fluctuations and the cyclic behavior correspond to two distinct but interacting processes.


Descriptors :   *DYNAMICS , *CHAOS , *SOLAR CYCLE , *SUNSPOTS , MATHEMATICAL MODELS , VARIATIONS , SMOOTHING(MATHEMATICS) , PERIODIC VARIATIONS , SOLAR ACTIVITY , NONLINEAR SYSTEMS , COUPLING(INTERACTION) , OSCILLATORS


Subject Categories : Astrophysics
      Numerical Mathematics
      Theoretical Mathematics


Distribution Statement : APPROVED FOR PUBLIC RELEASE