Swarm is ESA's first Earth observation constellation of satellites. Gases in the ionosphere are excited by solar radiation to form ions, which have an electrical charge.ДЄ paper, published recently in Geophysical Research Letters, describes how scientists from research centers in Poland used magnetic field data from ESA's constellation of Swarm satellites, lightning observations from the Geostationary Lightning Mapper and from the ground-based World Extremely Low Frequency Radiolocation Array (WERA) to provide evidence of links between transient luminous events and magnetic-field fluctuations in the upper ionosphere. The ionosphere is very active part of the atmosphere, responding to the energy it absorbs from the Sun. Scientists have long been interested in understanding if lightning propagating to higher in the ionosphere can cause fluctuations in Earth's magnetic field. They appear as large, but weak flashes of red and usually happen at the same time as the cloud-to-ground lightning we all know. Sprites, for example are large electrical discharges that occur at an altitude of around 50вЂ“90 km, above large thunderstorm systems. There are several different types of transient luminous events such as sprites, jets and elves, each with their own characteristics.

Remarkably, during similar events, photographs have been taken from the ground at the exact same time as the event was recorded in the Swarm missionвЂ™s data, leading to better insight into how this type of lightning propagates into space. Although ESAвЂ™s Swarm mission did not record this particular event, the video shows how quick these transient luminous events are. Sprites and presides filmed in the countryside near NГЅdek in the Czech Republic.

They are usually only captured by sensitive photographic equipment and, because they emit weak light, photographs can only be taken at night. They are very brief, lasting from less than a millisecond to two seconds, and rarely seen from the ground. Transient luminous events are optical phenomena that occur high up in the atmosphere and they are linked to electrical activity in underlying thunderstorms. In addition, these new findings could potentially improve scientific models of the ionized part of Earth's upper atmosphere-the ionosphere. This extraordinary three-way coincidence is leading to better insight into how this type of lightning propagates into space. The likelihood of this happening might seem pretty remote, but, remarkably, an observer for the Czech Institute of Atmospheric Physics who is also an avid ' lightning hunter' has taken photographs of these transient luminous events that not only coincide with measurements taken by ESA's Swarm satellite mission, but also with recordings taken from the ground. So, what are the chances of somebody taking photographs of these rarely seen, brief 'transient luminous events' at the exact same time as a satellite orbits directly above with the event leaving its signature in the satellite's data? While these flashes originate in storm clouds and strike downwards, a much more elusive type forms higher up in the atmosphere and shoots up towards space. We are all familiar with the bolts of lightning that accompany heavy storms. Now a scientific paper has been published about using Swarm to help provide evidence of links between transient luminous events and magnetic-field fluctuations in the upper ionosphere. The event caused fluctuations in the scalar magnetic field with amplitudes reaching 0.2 nT. The distance between the ground tracks of the satellites and the centre of the storm was about 500 km. Two of ESAвЂ™s Swarm satellites registered perturbations in their magnetic field data as they passed over Poland. This photograph of lightning sprites was taken from Czech Republic in August 2017 and it was the first time that an event of this type left its signature simultaneously in satellite data.