Figure demonstrating the process (1) when two opposite polarities of initial barycenter separation distance D ₀ are convergence; (2) the two opposite polarities are at their closest and a current sheet starts forming, where D _min is the minimum distance, with D ₀ > D _min; (3) the two opposite polarities are divergence from their closest distance, D _min, back to D ₀, and the associated current sheet is still developing above the photosphere; (4) reconnection takes place and a flare occurs above the polarity inversion line (PIL). After the distance between the polarity barycentres returns to the initial separation, D ₀, during a further evolution, this distance can now either decrease or increase (i.e., D ₁ < D ₀ or D ₁ > D ₀). D _C = D ₀−D _min in Figure 5 (right panel).