  The hemispheric asymmetry of the sunspot cycle is a real feature of the Sun.
However, its origin is still not well understood. Here we perform nonlinear
time series analysis of the sunspot area (and number) asymmetry to explore its
dynamics. By measuring the correlation dimension of the sunspot area asymmetry,
we conclude that there is no strange attractor in the data. Further computing
Higuchi's dimension, we conclude that the hemispheric asymmetry is largely
governed by stochastic noise. However, the behaviour of Hurst exponent reveals
that the time series is not completely determined by a memory-less stochastic
noise, rather there is a long-term persistence, which can go beyond two solar
cycles. Therefore, our study suggests that the hemispheric asymmetry of the
sunspot cycle is predominantly originated due to some irregular process in the
solar dynamo. The long-term persistence in the solar cycle asymmetry suggests
that the solar magnetic field has some memory in the convection zone.
