Potential analysis of sunspot parameters and behaviour of random noise

Abstract

Changes in solar magnetic field are responsible for initialisation and maintenance of different solar processes. Sunspots are clear manifestations of field variations and are good indicators of solar activity. Nature of activity can be well understood by analyzing the underlying sunspot dynamics. Techniques of potential analysis are used in this paper to investigate sunspot numbers and sunspot area, during the period 1875-2012, for finding out their stochastic behaviour. The presence of instabilities in the time series of sunspot numbers and sunspot area are examined in detail. The level of instability in sunspot numbers was observed to be maximum in the years 1953-1955, while that in sunspot area was maximum during 1887-1889. This study also concludes that random noise has a greater effect on dynamics of sunspot area than that on dynamics of sunspot numbers. Presence of high level of noise is noticed in both parameters during 1923-1925. Effect of random noise on the dynamics of sunspot number and area was shown to be very high during the years close to sunspot minima. Results reported can be helpful in predicting evolution of solar activity, which would be crucial in understanding solar-terrestrial phenomena.