  The plasma response to an externally generated, static, n=2, resonant
magnetic perturbation (RMP) in the pedestal region of DIII-D discharge #158115
is investigated. In this particular discharge, the resonant amplitudes of the
RMP are modulated in a cycloidal manner at a frequency of 1 Hz. Adopting the
plausible hypothesis that mode penetration at the top of the pedestal is a
necessary and sufficient condition for the RMP-induced suppression of edge
localized modes (ELMs), recent cylindrical, nonlinear,
reduced-magnetohydrodynamical (MHD) simulations performed by Hu, Nazikian, et
al., (2019) can account, in a quantitative fashion, for the density-pump out
and RMP-induced ELM suppression threshold observed in DIII-D discharge #158115.
The primary aim of this paper is to employ analytic theory to further simplify
the model of Hu, Nazikian, et al., in such a manner that a complete simulation
of RMP-induced ELM-suppression in a DIII-D H-mode discharge can be performed in
a matter of minutes of real time. A secondary aim is to gain a more exact
understanding of the physical mechanism that underlies RMP-induced ELM
suppression in the DIII-D tokamak.
