Wavelet spectrograms for events 1 (left) and 2 (right), corresponding to the onset phase of the SEP events. Top two panels: Magnetic field and velocity components. Bottom three panels: Wavelet spectrograms of the normalized magnetic helicity (σ_m), normalized cross helicity (σ_c), and normalized residual energy (σ_r). Black contours indicate magnetic flux ropes that satisfy the criteria |σ_m|≥0.6 and σ_r ≤ −0.5.