Time stasis field

A time stasis field was a phenomenon that would mean that an event could only be entered during a very narrow margin of time. The Alignment of Exodor was in a time stasis field, meaning the Eleventh Doctor had only one chance to see it and could only attempt to do so on a specific day. (TV: Closing Time)

During the Last Great Time War, the Daleks placed the Doctor's TARDIS in a time stasis field, seemingly only able to leave once the coordinates for the Neverwhen were programmed in. (AUDIO: A Thing of Guile)