Temporal evolution of the clockwise vortex that appeared within the spine of the filament (case 1) on 3 June 2023. Panels (a1)–(a4): Vortex observed by the NVST Hα images. The yellow arrows in panels (a1)–(a4) indicate the velocity fields of the vortex based on the DAVE technique. The cyan arrows in panels (a2) and (a3) indicate the speeds of features E1 and E2 from the DAVE technique, respectively. Panels (b1)–(b2): Hα images displaying temporal evolutions of E1 in panel (a2). The positions of E1 at two moments are marked with magenta and cyan symbols “×”, respectively. Cyan arrows indicate the evolution orientations. Panels (c1)–(c2): Similar to panels (b1)–(b2), but for E2 in panel (a3). Panels (d1)–(d3): AIA 171 Å images. The red arrows in panels (d1)–(d3) indicate the velocity fields. Panel (e): Average projection speeds with error bars of the vortex from the NVST Hα observations (panels (a1)–(a4)) and the AIA 171 Å data (panels (d1)–(d3)). An animation of NVST Hα observations from 3 June 2023 at 02:05:48 UT to 03:00:15 UT, showing the evolution of the vortex, is available online. The real-time duration of this animation is 8 s.