Equatorial plasma bubbles are an ionospheric
phenomenon near the Earth’s geomagnetic equator at night time. They affect radio waves by causing varying delays.

They degrade the performance of GPS . Different times of the year and location have different frequencies of occurrence.

Plasma bubbles form after dark when the sun stops
ionising the ionosphere. The ions recombine, forming a lower density layer. This layer can rise through the more ionised layers above via convection, which makes a plasma bubble. The bubbles are turbulent with irregular edges.