  Dynamic aperture (DA) is an important nonlinear property of a storage ring
lattice, which has a dominant effect on beam injection efficiency and beam
lifetime. Generally, minimizing both resonance driving terms (RDTs) and
amplitude dependent tune shifts is an essential condition for enlarging the DA.
In this paper, we study the correlation between the fluctuation of RDTs along
the ring and the DA area with double- and multi-bend achromat lattices. It is
found that minimizing the RDT fluctuations is more effective than minimizing
RDTs themselves in enlarging the DA, and thus can serve as a very powerful
indicator in the DA optimization. Besides, it is found that minimizing
lower-order RDT fluctuations can also reduce higher-order RDTs, which are not
only more computationally complicated but also more numerous. The effectiveness
of controlling the RDT fluctuations in enlarging the DA confirms that the local
cancellation of nonlinear effects used in some diffraction-limited storage ring
lattices is more effective than the global cancellation.
