α-induced total reaction cross sections based on the intranuclear cascade model

\ensuremath{\alpha}-induced total reaction cross sections in the low-energy region below 400 MeV are investigated using an intranuclear cascade model based on the extended framework for nucleon- and deuteron-induced reactions. Experimental data for $^{12}\mathrm{C}$, $^{28}\mathrm{Si}$, $^{40}\mathrm{Ca}$, and $^{208}\mathrm{Pb}$ targets are reproduced well by calculations performed with reasonable parameters close to those determined in other studies. It is shown that two effects, namely discrete level constraint (DLC) and the Coulomb effect, provide important contributions that depend on the incident energy and target. The DLC effect is limited to a narrow region of low energy and is very important in light targets. The Coulomb effect is decisive on cross sections in $^{208}\mathrm{Pb}$, while the DLC contribution for the heavy target is small. It is concluded that these effects determine the curve of incident-energy dependence of the total reaction cross sections, and this trend in the contribution of both effects is consistent with proton- and deuteron-induced total reaction cross sections.