(a): SDC18 continuum emission at 850 μm with an angular resolution of 14.6ʺ with JCMT/POL-2 in contours and magnetic field segments, capturing the entire filament and the filament-embedded clumps, SDC18-N and SDC18-S (green boxes), zoomed in the middle and right panels. The contours are 50, 500, and 1000 mJy beam⁻¹. (b), (c): Continuum emission at 1.3 mm in contours and magnetic field segments of SDC18-N (b) and SDC18-S (c) with an angular resolution of 4.41ʺ × 3.32ʺ with the SMA, capturing the isolated clumps resolving out diffuser and more extended emission. Solid black contours represent the Stokes I flux levels at 15, 40, and 80σ_I, while dashed black contours show -5σ_I. (d), (e): The same as the middle panels but with an angular resolution of 1.45ʺ × 1.25ʺ, capturing the clump-embedded cores revealing fragmentation of the larger clump. Solid black contours are 7, 30, and 45σ_I Stokes I flux levels, while dashed black contours are -7σ_I. The segments in all panels show magnetic field orientations with P > 3σ_P detections in blue and 3σ_P > P > 2σ_P detections in red. The right panels display magnetic field segments gridded at half of the synthesized beam resolution. The segments in the middle panels are overgridded for a sharper visualization, but only data at half of the synthesized beam are used for the further analysis.