Equatorial plasma bubbles are an
ionospheric
The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays a ...
phenomenon near the Earth's geomagnetic equator at night time. They affect radio waves by causing varying delays. They degrade the performance of
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
.
Different times of the year and locations have different frequencies of occurrence. In
Northern Australia
The unofficial geographic term Northern Australia includes those parts of Queensland and Western Australia north of latitude 26° and all of the Northern Territory. Those local government areas of Western Australia and Queensland that lie p ...
, the most common times are February to April and August to October, when a plasma bubble is expected every night.
Plasma bubbles have dimensions around 100 km.
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 ionized layers above via convection, which makes a plasma bubble. The bubbles are turbulent with irregular edges.
An equatorial plasma bubble could have affected the
Battle of Shah-i-Kot by disabling communications from a communications satellite to a helicopter.
References
Ionosphere
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