A long-lived band of plasma density enhancement at mid-latitudes during the 2003 Halloween magnetic storm

► A post-midnight streak of high plasma density was encountered during a superstorm. ► We examine its particle/magnetic signatures, the 3D structure, and time evolution. ► This is the first dedicated study of a post-midnight SED. ► This is the first report on the magnetic signature of a SED. ► We have presented the first 3D image of a SED in the middle of the Pacific Ocean.