https://www.sciencedaily.com/releases/2022/07/220715105747.htm

Shortly after sunset, pockets of super-heated gas called 'plasma bubbles' form in the upper atmosphere and stretch into space (up to 900km above the Earth's surface). These bubbles start small and grow rapidly -- from the size of a football pitch to that of a small country in just a couple of hours. As the bubbles grow bigger, they can prevent satellites from communicating with the Earth by blocking and warping their radio signals.

To predict plasma bubbles, a team of researchers has collated 8 years of data from the SWARM satellite mission. The spacecraft has an automatic bubble detector on-board called the Ionospheric Bubble Index. This compares changes in the density of electrons and the magnetic field strength to check if bubbles are present: a strong correlation between the two indicates the presence of a plasma bubble.