Teraport Area Denial or TAD systems are devices which project a field in which teraports cannot be survivably used, either entering or leaving. Virtually all inhabited planets and other habitats have large interdiction zones to protect themselves form attack with teraport-equipped munitions or raiders, and warships project TAD fields for the same reason and also to prevent teraport-capable targets from escaping. The most common interdiction devices are made by Strohl Munitions. TAD fields do not interfere with each other, even if overlapped. Most new teraport systems have safety overrides designed to keep them from being used to enter or leave interdicted space. If the attempt is made anyway, the teraported object will probably be disintegrated.
TAD fields can be defeated by use of teraport cages, but once detected, a cage can be overwhelmed by increasing the field intensity or bringing additional TAD systems online. The Fleetmind also has a method for defeating TAD systems, but it requires immense energy, and he currently can't spare any of that. High-density TAD fields are an effective weapon against the Pa'anuri.