A massive lightning bolt that soared 80km into space above a storm offered mysterious new insights into the ‘giant jets’, which carry massive amounts of electrical charge.
Scientists believe that as many as 50,000 ‘giant jets’ could occur each year – and the new research may help explain why they shoot into space instead of descending towards the ground. The gigantic jet emerged from a storm in Oklahoma and is the most powerful ever studied.
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Normal lightning carries less than five coulombs of electrical charge: the gigantic jet moved about 300 coulombs of electrical charge into the ionosphere, the lower edge of space.
The upward discharge included structures known as ‘leaders’ that were 4,400C as well as coils of cooler plasma.
Corresponding author Levi Boggs, a researcher at the Georgia Tech Research Institute (GTRI), said: “We were able to map this gigantic jet in three dimensions with high-quality data.
“We were able to see very high frequency (VHF) sources above the cloud top, which had not been seen before at this level of detail.
“Using satellite and radar data, we were able to learn where the very hot leading portion of the discharge was located above the cloud.”
Steve Cummer, professor of electrical and computer engineering at Duke, uses the electromagnetic waves that rays emit to study the powerful phenomenon.
It operates a research site where sensors similar to conventional antennas are placed in an empty field, waiting to pick up signals from locally occurring storms.
Cummer said: “VHF and optical signals have definitively confirmed what researchers suspected but have yet to prove: that the lightning’s VHF radio is emitted by small structures called serpentines that are at the tip of the developing lightning bolt, while the strongest electrical current flows significantly behind this tip in an electrically conductive channel called a leader.
A massive lightning bolt that soared 50 miles into space above a storm offered new insights into mysterious ‘giant jets’, which carry massive amounts of electrical charge.
Scientists believe that up to 50,000 ‘giant jets’ could occur each year – and the new research may help explain why they shoot into space instead of descending towards the ground.
The gigantic jet emerged from a storm in Oklahoma and is the most powerful ever studied.
Normal lightning carries less than five coulombs of electrical charge: the gigantic jet moved about 300 coulombs of electrical charge into the ionosphere, the lower edge of space.
The upward discharge included structures known as ‘leaders’ that were 4,400C as well as coils of cooler plasma.
Corresponding author Levi Boggs, a researcher at the Georgia Tech Research Institute (GTRI), said: “We were able to map this gigantic jet in three dimensions with high-quality data.
“We were able to see very high frequency (VHF) sources above the cloud top, which had not been seen before at this level of detail.
“Using satellite and radar data, we were able to learn where the very hot leading portion of the discharge was located above the cloud.”
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Steve Cummer, professor of electrical and computer engineering at Duke, uses the electromagnetic waves that rays emit to study the powerful phenomenon.
It operates a research site where sensors similar to conventional antennas are placed in an empty field, waiting to pick up signals from locally occurring storms.
Cummer said: “VHF and optical signals have definitively confirmed what researchers suspected but have yet to prove: that the lightning’s VHF radio is emitted by small structures called serpentines that are at the tip of the developing lightning bolt, while the strongest electrical current flows significantly behind this tip in an electrically conductive channel called a leader.
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Gigantic jets have been observed and studied over the past two decades, but as there is no specific observation system to look for them, detections have been rare.
Boggs learned of the Oklahoma event from a colleague, who told him about a gigantic jet that had been photographed by a citizen-scientist who had a low-light camera in operation on May 14, 2018.
Fortunately, the event took place at a location with a VHF ray mapping system nearby, within range of two Next Generation Weather Radar (NEXRAD) sites and accessible to instruments on satellites from the Geostationary Operational Environmental Satellite (GOES) network. NOAA.
Boggs determined that data from these systems was available and worked with colleagues to gather it for analysis.
Boggs explained: “Detailed data showed that these cool streamers begin their propagation just above the cloud top.
“They propagate down to the lower ionosphere at an altitude of 50 to 60 miles, making a direct electrical connection between the top of the cloud and the lower ionosphere, which is the lower edge of space.”
Why do gigantic jets launch payloads into space? The researchers speculate that something may be blocking the flow of charge downwards – or towards other clouds.
Records from the Oklahoma event show little lightning activity from the storm before firing the gigantic record jet.
Boggs said: “For whatever reason, there is usually a suppression of cloud-to-ground discharges.
“There is a buildup of negative charge, and so we think that conditions at the top of the storm weaken the upper layer of charge, which is usually positive. In the absence of the lightning strikes we normally see, the gigantic jet can alleviate the buildup of excess negative charge in the cloud.”
Estimates for the frequency of gigantic jets range from 1,000 per year to 50,000 per year.
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