Normalized residual energy (σ_r) vs. normalized cross helicity (σ_c) for all HSs with |σ_m|≥0.7 within the < 1 mHz PDS events in out list. The HSs are color-coded based on the average solar wind speed, with black and red circles corresponding to Vsw < 500 km/s and Vsw ≥ 500 km/s, respectively. The shaded green, yellow, and magenta areas represent the regions that likely contain flux ropes, Alfvénic HSs, and complex HSs, respectively.