Measurements of DM structure functions as a function of time lag are displayed in black circles. The black diamond represents the DM structure function when the time lag equals the time scale of DISS (τ_d ≈ 3 minutes), which is included in the fitting. The red and blue dashed lines are the fitting result with D_ϕ(τ)∝τ^β − 2 and fixed β of 11/3, respectively. Only points to the left of the grey line are involved in the fitting due to the possible bias introduced by the sudden decrease.