Velocity-resolved relationship between filamentary H Ⅰ structure and magnetic-field orientation in the Orion-Eridanus superbubble region

Magnetic fields are a fundamental property of diffuse interstellar medium． Previous studies have shown that filamentary H Ⅰ structure often follows the plane-of-sky magnetic field inferred from polarized dust emission． Leveraging high-sensitivity FAST/CRAFTS H Ⅰ survey and Planck 353 GHz dust polarization, we target the Orion-Eridanus superbubble environment and map relative orientation between H Ⅰ filaments and dust-inferred magnetic field across v_LSR = −15 to 15 km·s⁻¹． We find a clear environmental bifurcation: exterior to the projected shell, low-velocity gas (−15 ≤ v_LSR < 0 km·s⁻¹) shows large and spatially coherent misalignment, whereas higher-velocity exterior gas aligns significantly better． The interior remains comparably well-aligned across all velocities, with little velocity dependence． Therefore broad H Ⅰ-dust alignment commonly seen in velocity-integrated studies does not apply uniformly to all kinematic components in the Orion-Eridanus environment． The spatially coherent low-velocity exterior structure represents a distinct component with enhanced misalignment, providing a new observational clue to the origin of geometrically differentiated atomic gas in a feedback-shaped environment.