This calls into question the definition of AC and DC.
Lightning is a form of electrical discharge, and it is more accurately described as a transient, high-voltage, high-current electrical flow. The nature of lightning is complex, involving the movement of electric charge within clouds and between the atmosphere and the ground.
However, if we were to simplify the classification, lightning is often considered more like a direct current (DC) phenomenon. This is because lightning doesn’t consistently flow in one direction but involves the movement of electric charge between the atmosphere and the ground. In contrast, alternating current (AC) regularly changes direction, typically in a sinusoidal waveform.
In essence, while lightning doesn’t perfectly fit the characteristics of either AC or DC, it is often likened more to DC due to the nature of its electrical flow.
Its not continuous for the foreseeable past and the foreseeable future. So its not constant where a constant voltage (like a battery) is DC, so its not DC by the constant definition.
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By some definitions the current only goes one way so its DC by that definition, but that’s weak because you could argue its a positive and negative signal with a DC offset.
But on the other hand it doesn’t repeat in alternating cycles so that’s another argument against AC.
In my rather technical definition it is a pulse of limited time duration (the beginning and end are within some easily predictable time window) and thereby can be analyzed by finite AC signal techniques, it has frequency content that is not all in bin zero of the FFT if you do a frequency transform, therefore its an AC event. Because the initial transition and breakdown is very fast there are frequency components that go from very low frequencies to radio frequencies (surely if you are over 30 years old you have heard lightning generated noise on AM radio).
It’s a pulse. A transient, It is unipolar, it does not oscillate although most tend to repeat rapidly I hear. You can’t classify transients as AC or DC.
Lightning, a spectacular and powerful force of nature, has intrigued scientists and enthusiasts for centuries. As we marvel at its dazzling display, questions about the nature of lightning often arise. Is it more akin to the direct current (DC) powering our devices or the alternating current (AC) that courses through our electrical grids? Let’s delve into the electrifying world of lightning to uncover its true nature.
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The Dynamics of Lightning:
At its core, lightning is a massive electrical discharge that occurs within thunderstorms. It is the result of the complex interactions between atmospheric elements, particularly the buildup and release of electrical charge. To understand whether lightning is more like AC or DC, we must first grasp the fundamental principles of these two types of electrical currents.
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Alternating Current (AC):
AC is characterized by its oscillating flow of electric charge, regularly changing direction. This type of current is what powers our homes, offices, and industries. The electrical energy generated at power plants is typically transmitted as AC over long distances before being converted to various voltages for different applications.
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Direct Current (DC):
DC, on the other hand, flows in a single, constant direction. Batteries, solar cells, and many electronic devices rely on direct current. Unlike AC, DC does not undergo periodic reversals in direction, maintaining a continuous flow of electric charge.
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Decoding Lightning’s Nature:
While it might be tempting to classify lightning strictly as either AC or DC, the truth is more nuanced. Lightning exhibits characteristics of both types of current. Initially, a lightning bolt forms as a series of stepped leaders, which resemble a direct current flow. However, when the final discharge occurs, it takes the form of a rapid and oscillating current, akin to alternating current.
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AC in the Atmosphere:
Interestingly, the atmosphere itself contains a form of AC known as “atmospheric electricity.” This is a natural occurrence where electrical charges accumulate in the atmosphere, leading to phenomena such as lightning. The nature of the electrical discharge in lightning is, therefore, a dynamic interplay between direct and alternating current characteristics.
In the electrifying dance of lightning across the skies, we witness a fascinating blend of both AC and DC characteristics. The natural processes that generate lightning involve a combination of direct current-like stepped leaders and the rapid, oscillatory discharge that resembles alternating current. As we continue to explore and understand the complexities of this awe-inspiring phenomenon, we gain deeper insights into the intricacies of electrical forces in our natural world. Lightning, in its essence, defies easy categorization, highlighting the dynamic and diverse nature of electrical phenomena in our atmosphere.