Dynamics of Sunspot Light Bridges as Revealed by High-Resolution Images from Hinode

We present G-band and Ca ii H filtergrams of two sunspot light bridges in NOAA AR 10953 taken from the 50-cm Solar Optical Telescope onboard the Japanese space satellite Hinode on 1 May 2007. The two light bridges differ in structure, with one of them resembling the filamentary penumbra and the other possessing a dark central lane running along the axis of the bridge having a width of 170 km, which is close to the diffraction limit of the telescope. Velocity measurements of the light bridges using proper motion displacements of inhomogeneities, averaged over the entire time series, show a nonuniform flow with velocities peaking at 250 and 180 m s⁻¹ for the two bridges, respectively. We report observations of an archlike structure over one of the light bridges in the Ca images. Brightness enhancements are seen traveling along this arch as well as along the light bridge. Observations suggest that these enhancements over light bridges could possibly be a signature of lower chromospheric heating.