The International Space Station discovered an exotic type of inverted lightning bolt, a blue beam (illustrated), that flew off a storm cloud into the stratosphere in 2019. DTU SPACE, DANIEL SCHMELLING / MOUNT VISUAL
An interesting piece of paper that may explain a rare type of lighting, the blue jet.
Blue jets are lightning-like, atmospheric electrical discharges lasting several hundred milliseconds that fan out into cones as they spread from the top of the storm clouds into the stratosphere1. They are believed to cause an electrical breakdown between the positively charged top of a cloud and a layer of negative charge on the cloud boundary and in the air above. The division forms a leader who, as it spreads upwards, merges into Streamer23.
However, the properties of the conductor and the height to which it extends above the clouds are not well characterized4. Blue millisecond flashes in cloud cover5,6 have previously been associated with close bipolar events7,8, which are 10 to 30 microsecond pulses in broadband electric field recordings, accompanied by intense bursts of radiation at 3 to 300 megahertz from short discharges (derived) canal lengths (less than a kilometer) 9–11.
Here we report on spectral measurements from the International Space Station, which provides an unobstructed view of storm clouds with a temporal resolution of 10 microseconds. We observe five intense blue flashes of about 10 microseconds from a thunderstorm cell. A flash of lightning triggers a pulsating blue beam to the stratopause (the interface between the stratosphere and ionosphere). The flashes observed were accompanied by “elves” 12 in the ionosphere. The emissions from lightning conductors in the red spectral band are faint and localized, suggesting that the lightning and beam are streamer ionization waves and that the beacons are short and localized at their origin.
We propose that the microsecond flashes are the optical equivalent of negative close bipolar events observed in radio waves. These are known to trigger lightning bolts in the cloud and on the ground and blue lightning bolts into the stratosphere, as reported here.
Full article here.
Here is a description of the paper from ScienceNews
From Maria Temming
January 21, 2021 at 1:12 p.m.
Scientists finally got a clear view of the spark that sets off an exotic type of lightning bolt called a blue beam.
Blue jets race up from storm clouds into the stratosphere and reach heights of up to 50 kilometers in less than a second. While ordinary lightning strikes a mixture of gases in the lower atmosphere to glow white, blue jets primarily excite stratospheric nitrogen to create their distinctive blue hue.
Blue jets have been observed from the ground and from aircraft for years, but it’s hard to tell how they form without getting high above the clouds. Now instruments on the International Space Station have discovered a blue beam emanating from an extremely short, bright electrical surge near the top of a storm cloud, researchers report online on January 20 in Nature.
Understanding blue jets and other upper atmosphere phenomena related to thunderstorms such as sprites (SN: 06/14/02) and elves (SN: 12/23/95) is important as these events can affect the way radio waves travel through the Migrating waters, according to Penn State space physicist Victor Pasko, who was not involved in the work, this may have an impact on communications technologies.
Full article here
ScienceNews article here