Unraveling the Mysteries of “Gigantic Jet” Lightning Bursts That Reach 50 Miles Into Space

A thorough 3D analysis of a large electrical discharge that ascended 50 miles into space above an Oklahoma thunderstorm has revealed new details about the mysterious atmospheric phenomena known as giant jets. The Oklahoma discharge carried 100 times as much electrical charge as a regular thunderstorm lightning bolt, making it the most potent enormous jet that has been analyzed to date.

An estimated 300 coulombs of electrical charge were transferred by the enormous jet from the thunderstorm into the ionosphere, which is at the lower border of space. Less than five coulombs are typically carried by a typical lightning bolt between a cloud and the earth or within a cloud. Streamers of plasma that were relatively chilly (about 200 degrees Celsius/400 degrees Fahrenheit) were present in the upward discharge. It also included structures known as leaders, which are extremely hot and reach temperatures of more than 8,000 degrees Fahrenheit (4,400 degrees Celsius).

According to the corresponding author of the study, Levi Boggs, a research scientist at the Georgia Tech Research Institute (GTRI), "We were able to map this enormous jet in three dimensions using exceptionally high-quality data." "We were able to observe very high frequency (VHF) sources above the cloud top, which had never been observed in such detail before. We were able to determine the location of the highly hot leader portion of the discharge above the cloud using satellite and radar data.

A multi-organizational research team was involved in Boggs' work. Universities Space Research Association (USRA), Texas Tech University, University of New Hampshire, Politecnica de Catalunya, Duke University, University of Oklahoma, National Severe Storms Laboratory of NOAA, and Los Alamos National Laboratory were also represented. The study is published on August 3, 2022, in Science Advances, a multidisciplinary, peer-reviewed, open-access publication.

Professor of electrical and computer engineering at Duke University Steve Cummer studies the potent phenomena using the electromagnetic waves that lightning releases. He runs a research facility with sensors arranged in a field that is otherwise unoccupied, waiting to pick up signals from nearby storms. These sensors resemble conventional antennas.

The VHF radio from lightning is emitted by small structures called streamers that are at the very tip of the developing lightning, while the strongest electric current flows significantly behind this tip in an electrically conducting channel called a leader, Cummer said. "The VHF and optical signals definitively confirmed what researchers had suspected but not yet proven," he added.

The study was distinctive in that it found that the 3D locations for the lightning's optical emissions were far beyond the cloud tops, according to Doug Mach, one of the paper's co-authors at the Universities Space Research Association (USRA).

"It was a remarkable event and gives us a lot more information on giant jets because the enormous jet was spotted by numerous systems, including the Lightning Mapping Array and two geostationary optical lightning instruments," said Mach. More significantly, the Geostationary Lightning Mapper (GLM) instrument suite was used for the first time to image a massive jet in three dimensions above the clouds.

Over the last 20 years, huge jets have been spotted and analyzed. However, detections have been scarce because there is no particular observing technique to seek for them. Boggs first heard about the Oklahoma incident from a coworker who informed him of a massive jet that had been seen on camera on May 14, 2018, by a citizen-scientist using a low-light camera.

Fortunately, the event occurred in an area that was accessible to instrumentation on satellites from NOAA's Geostationary Operational Environmental Satellite (GOES) network, within range of two Next Generation Weather Radar (NEXRAD) stations, and close to a VHF lightning mapping system. After determining that the data from those systems was accessible, Boggs collaborated with others to compile it for study.

According to Boggs, "the precise data showed that such frigid streamers start their dispersion directly above the cloud top." They spread all the way to the lower ionosphere, which is the lower edge of space, at a height of 50 to 60 miles, creating a direct electrical link between the cloud top and the lower ionosphere.

In less over a second, that connection transmits thousands of amps of current. As is typical of enormous jets, the upward discharge carried negative charge from the cloud to the ionosphere.

The results showed that optical emissions from the lightning leaders stayed close to the cloud top at an altitude of 15 to 20 kilometers as the discharge climbed from the cloud top, whereas VHF radio sources were discovered at altitudes of 22 to 45 kilometers (13 to 28 miles) (9 to 12 miles). The simultaneous 3D radio and optical data show that streamer corona emissions are detected by VHF lightning networks rather than leader channel emissions, which has extensive implications for lightning physics outside the realm of enormous jets.

Why do the enormous jets launch energy into space? According to researchers, something may be preventing the charge from moving downhill or toward other clouds. Before the storm shot the record-breaking, enormous jet, the Oklahoma event's records reveal little lightning activity from the storm.

Cloud-to-ground discharges are typically suppressed for unknown reasons, according to Boggs. We believe that the conditions in the storm top weaken the topmost charge layer, which is typically positive, as a result of the development of negative charge. The massive jet could ease the cloud's buildup of surplus negative charge in the absence of the typical lightning discharges.

Gigantic jets, a type of enigmatic transitory luminous occurrences, are currently the subject of numerous unresolved issues. This is because to the fact that observations of them are uncommon and happen accidentally, either by pilots or other passengers spotting them while flying or by ground observers using night-scanning cameras.

Estimates for the annual frequency of enormous jets range from 1,000 to 50,000. Tropical parts of the world have seen more reports of them. The Oklahoma enormous jet, which was twice as powerful as the next-strongest one, wasn't a part of a series of tropical cyclones, though.

Gigantic jets might affect the functionality of satellites in low-Earth orbit in addition to being amusing, according to Boggs. Signal loss and performance difficulties can get worse as more of those spacecraft are launched. Technology like over-the-horizon radars that reflect radio waves off the ionosphere may be impacted by the enormous jets.

Upward propagation of enormous jets shown by 3D radio and optical mapping, Levi D. Boggs, Doug Mach, Eric Bruning, Ningyu Liu, Oscar A. van der Velde, Joan Montanya, Steve Cummer, Kevin Palivec, Vanna Chmielewski, Don MacGorman, and Michael Peterson, Science Advances, 3 August 2022.

Boggs is associated with the Severe Storms Research Center, which was founded at GTRI to create better technology for tornado warnings and other severe storms. A component of such effort is the research on enormous jets and other atmospheric phenomena.

By GEORGIA TECH RESEARCH INSTITUTE