Large-Scale Latitude-time Relationships Between the Green-Line Corona and Sunspot Activity During Solar Cycles 18-24

We investigate the latitude-time relationship between the solar green-line corona and sunspot activity during Solar Cycles 18-24 using homogeneous coronal observations and a Gaussian representation of sunspot activity fields. The activity-field model is constructed from individual sunspot areas and latitudes in order to describe the large-scale spatial organization of solar magnetic activity more realistically than traditional sunspot number or sunspot area indices. The analysis reveals a stable double-peaked latitude-dependent correlation structure centered on the active-region belts, where the strongest corona-sunspot correlations are observed. The latitude profiles remain remarkably similar from cycle to cycle, indicating that the large-scale relationship between coronal emission and photospheric activity is largely independent of cycle amplitude and parity. The lag-correlation profiles exhibit broad positive lag plateaus in most cycles. Although formal lag-correlation maxima occur at positive lags, surrogate-data tests indicate that these maxima are generally not statistically distinguishable from neighboring lag values. The results therefore suggest temporal persistence and memory of large-scale coronal magnetic structures rather than a precisely defined physical delay. The Gaussian activity-field representation produces substantially stronger and more coherent correlations with the green-line corona than conventional sunspot measures, supporting the interpretation that the large-scale distribution of magnetic activity, rather than individual sunspots alone, governs the evolution of the large-scale corona.