Summary plot in the 3-min vicinity of the 2021 November 3 shock. Panels a–f: same as Fig. 2, but on a smaller timescale. Panel g: spectrogram of the trace power spectral density of the magnetic field fluctuations, obtained from the wavelet analysis (Torrence & Compo 1998). Panel h: spectrogram of the reduced magnetic helicity, σ_m, on the YZ plane of the spacecraft frame (He et al. 2011). If a wave vector points along +X (toward the Sun), positive σ_m (red) indicates right-hand polarization, and negative σ_m (blue) indicates left-hand polarization, and vice versa. The vertical dashed red line marks the shock front. The ∼26-s upstream interval bounded by the dashed blue line and the shock front is labeled U1. The ∼15-s downstream interval bounded by the shock front and the dashed purple line is labeled D1.