Superbolts: Giant Discharges at the Heart of the Storm

A superbolt lights up the atmosphere above the ocean — An exceptionally powerful superbolt striking in the middle of a night storm, illuminating the surroundings with an intensity comparable to daylight.
Image source: astronoo.com (new window)

Scientific Summary

This article examines superbolts, lightning bolts whose luminous energy is approximately 1000 times greater than that of a classic bolt, reaching up to 100 gigajoules. Their formation results from a rare combination of conditions: extreme electric fields (up to 10⁶ V/m) within cumulonimbus clouds, great cloud height (>12 km), and a relativistic electron avalanche (RREA) mechanism. This process accelerates electrons to near-light speeds, creating a stable, very hot (30,000 to 50,000 °C) ionized channel. These phenomena, mostly observed over oceans, occur in less than 0.01% of thunderstorms.

What is a superbolt and why is it so powerful?

A superbolt is a lightning bolt of exceptional power, releasing 100 to 1000 times more energy than a normal bolt. This power comes from an extreme electric field (10⁶ V/m) inside storms, which triggers a relativistic electron avalanche (RREA). These electrons, accelerated to nearly the speed of light, ionize an air channel that remains stable for several milliseconds, allowing the transfer of a colossal current (up to 500,000 A). These rare conditions often occur over oceans, transforming the storm into a giant natural battery.

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What is a superbolt?

The term superbolt (lightning bolt of exceptionally high intensity) (or super-lightning) refers to a rare and extremely energetic category of lightning observed in Earth's atmosphere. A superbolt is an atmospheric electrical phenomenon characterized by a discharge a thousand times more intense than a classic lightning bolt. Their brightness is such that they can be observed from space by weather satellites. While a classic lightning bolt releases about 1 gigajoule of energy, superbolts can reach energies exceeding 100 gigajoules, making them 100 to 1000 times more powerful than ordinary lightning.

These exceptional meteorological phenomena were first identified in the 1970s by physicist Bernard Vonnegut (1914-1997), but it was only with modern satellites that their systematic study became possible.

Comparison of physical parameters between a classic lightning bolt and a superbolt
Physical parameter	Classic lightning	Superbolt	Ratio or remark
Light energy emitted	≈ \(10^8\ \text{J}\)	≈ \(10^{11}\ \text{J}\)	About 1000 times more intense
Duration of discharge	\(10^{-4}\ \text{s}\) (≈ 100 µs)	1 to 10 × \(10^{-3}\ \text{s}\)	Duration 10 to 100 times longer
Maximum current	≈ 30,000 A	200,000 to 500,000 A	Up to 15 times higher
Temperature of the ionized channel	20,000 to 30,000 °C	30,000 to 50,000 °C	Hotter and more stable plasma
Local electric field	\(E \approx 10^5\ \text{V/m}\)	\(E \approx 10^6\ \text{V/m}\)	10 times stronger electric field
Duration of channel ionization	A few microseconds	Up to several milliseconds	Almost continuous ionization
Average altitude of occurrence	5 to 10 km	10 to 15 km (cloud tops)	Cold and unstable regions

Source: Holzworth et al., *Geophysical Research Letters*, 2020 (new window) – satellite data from OTD (optical Transient Detector) and LIS (lightning Imaging Sensor).

Formation Mechanisms of Superbolts and Atmospheric Environment

Exceptional conditions for the appearance of superbolts

The genesis of a superbolt results from a rare combination of atmospheric conditions (electrostatic, thermodynamic, and particle-scale physical) within cumulonimbus clouds. These phenomena occur when a charge imbalance reaches a critical threshold, making possible a self-sustaining discharge of colossal energy. These conditions are only met in less than 0.01% of storms observed on a planetary scale.

Charge dynamics in the cloud

In a storm cloud, ice crystals, graupel, and supercooled water droplets constantly collide. During these collisions, a small transfer of electrons occurs, most often from graupel to ice crystals. This multitude of exchanges eventually creates a natural battery: the upper part of the cloud becomes positive, while its central zone accumulates negative charges. The electric field thus generated can reach considerable values, on the order of \(E \approx 10^5 - 10^6\ \text{V/m}\).

Triggering the discharge

This electric field eventually exceeds the dielectric strength of air (\(3 \times 10^6\ \text{V/m}\)), i.e., the limit beyond which air ceases to be an insulator. At this point, a partially ionized channel progresses in successive small steps, each locally reinforcing the electric field around it.

Relativistic electron avalanche

When the field reaches extreme values, exceeding \(10^6\ \text{V/m}\), free electrons are accelerated to speeds close to that of light. They then enter a relativistic electron avalanche, a process called RREA (relativistic Runaway Electron Avalanche). This mechanism converts part of the electrostatic field's energy into a gigantic electric current. The ionized channel heats up abruptly, reaching temperatures of tens of thousands of degrees: the air expands violently and produces a luminous and sonic shock wave, the superbolt.

Favorable environments

Superbolts mainly appear above oceans, where the conductivity of humid air favors extreme discharges, but they can also occur on continents, where charge gradients between cloud layers reach critical values. Observations indicate a potential difference reaching several gigavolts (billions of volts).

Possible origin of the power of a superbolt

Factors contributing to the exceptional power of superbolts
Key factor	Mechanism	Impact on power	Favorable conditions
Cloud height	Greater distance between charge centers = increased potential difference	Increase in available potential energy for discharge	Cumulonimbus with great vertical extent (>12 km)
Intensity of the electric field	Electric field significantly exceeding the dielectric strength of air	More efficient electron acceleration and amplification of the RREA phenomenon	Exceptional concentration of charges in the cloud
Duration of discharge	Prolonged charge transfer in the ionized channel	Greater temporal integration of current	Exceptional stability of the lightning channel
Relativistic advancement (RREA)	Avalanche of electrons reaching relativistic speeds	Exponential multiplication of charge carriers	Extreme electric fields (>10^6 V/m)
Geometry of discharge	Discharge extending over greater horizontal or vertical distances	Larger volume of ionized air and increased charge transfer	Large-scale storms
Atmospheric conditions	Cold, dry air at altitude favoring charge accumulation	Reduction of leaks and improved insulation	Unstable air masses with strong thermal gradient

FAQ: All about superbolts

What is the main difference between a classic lightning bolt and a superbolt?

The main difference lies in their energy and power. A classic lightning bolt releases about 1 gigajoule, while a superbolt can release more than 100 gigajoules, 100 to 1000 times more. This difference is explained by a much higher peak current (up to 500,000 A vs 30,000 A), a longer discharge duration (several milliseconds vs 100 microseconds), and an electric field ten times more intense.

Where and when do superbolts most frequently occur?

Superbolts predominantly appear over oceans, where the conductivity of humid air favors extreme discharges. They can also occur over continents. They are associated with large vertical extension cumulonimbus clouds (over 12 km) and unstable air masses with strong thermal gradients. Their occurrence is extremely rare, representing less than 0.01% of observed thunderstorms.