Paraphrase the following text using more academic and scientific language Use a neutral tone and avoid repetitions of words and phrases：When the magnitude of noise strength $f_n$ is relatively smaller

In cases where the noise strength $f_n$ is relatively smaller than the kick strength $K$, perturbation theory may be utilized to expand the exponential term $e^{-ik_ncos^2\theta}$ within the Floquet operator $\hat{F}^{k_n}$. The expansion can be expressed as Eq. (1), with terms greater than $k^2_n$ being disregarded. Upon substituting the expanded equation into Eq. (\ref{fkn}) and Eq. (\ref{asr}), and grouping terms with the same $k_n$ order, Eq. (2) is obtained. The expression for $A_r(N)$ is approximated, and $C_r$ signifies a constant.