Left: the orbital parameter space of the WD-MBH system in which diffusive-tide rpTDEs are expected is colored in yellow. The black cross marks the fiducial orbital parameters (see Table 1). The black solid line denotes the boundary for diffusive growth assuming Q = 10⁶ = ω_aP₀, while the dotted line (with Q = 2 × 10³) indicates the marginal boundary for the fiducial model. The magenta line represents the threshold for diffusive growth driven by GW backreaction (S. Y. Lau & H. Yu 2025). The red solid (dotted) line shows the threshold for diffusive growth induced by nonlinear anharmonicity (linear tidal backreaction). The blue line corresponds to the onset of prompt disruption. Right: same as for the left panel, but for an MS-MBH system with α = 0.8. A potential evolutionary pathway is shown by the arrowed lines: the MS star may be captured onto a wide orbit via the Hills mechanism (black star) and subsequently circularize, during which the diffusive tides are suppressed because of large dissipation. Once the fiducial point (cross) is reached, diffusive tides start to power rpTDEs. The MS star becomes denser as it loses mass, eventually quenching the eruptions (diamond).