Display of a particle scattering field around El-Adrel IV.
A particle scattering field is an energy field that, when projected into a planet's ionosphere, causes a hyperionization that disrupts all electromagnetic and subspace carriers, effectively rendering communications and transporter use through impossible. If the scattering field is thin, it may be possible to boost the annular confinement beam to allow transport through.
In 2368, the Tamarians induced a particle scattering field above the planet El-Adrel IV, where they had beamed Captain Jean-Luc Picard and Captain Dathon. This ensured that the both captains were trapped on the surface, though the Tamarians left the sensor channels clear so that the situation could be monitored. (TNG: "Darmok")