Scientists from the P. N. Lebedev Physical Institute of the Russian Academy of Sciences (LPI RAS) and the Moscow Institute of Physics and Technology (MIPT) conducted a series of experiments revealing the mechanisms of X-ray generation in artificial lightning. The study, published in Journal of Applied Physics, allowed for the first time to record the temporal and angular characteristics of this phenomenon with high accuracy, opening up new opportunities for studying natural lightning and developing technologies to protect against it.
In the experiments, scientists used a high-voltage setup that creates pulses with a voltage of up to 1 megavolt in an air gap of 55 cm. A system of 10 scintillation detectors, arranged in an arc with a step of 10 degrees, was used to register X-ray radiation. This made it possible not only to record flashes, but also to determine their directionality.
The main discovery was that X-ray radiation appears even before the lightning flash itself, at the moment when the voltage reaches its maximum value. At the same time, scientists discovered two different types of radiation. The first type propagates in all directions, but at high energies the radiation is directed towards the negative electrode (anode). The second type turned out to be more mysterious - these are high-energy rays that appear on the periphery of the main discharge, which has not yet found a complete explanation.
Physicists have established that the reason for the appearance of X-ray radiation lies in the behavior of electrons. Under the influence of enormous voltage, electrons accelerate to extremely high speeds and collide with air molecules, which leads to the appearance of X-ray radiation.
Our results show that hard X-ray radiation in atmospheric discharges is associated with ultrafast ionization processes. This opens the way to a more accurate modeling of natural electrical discharges, such as lightning.
This discovery will help to more accurately model lightning and develop methods to protect against it.
The studies conducted for the first time with high temporal and spatial accuracy established the time frame and angular characteristics of X-ray radiation in discharges. This allows us to revise the mechanisms of its generation and take into account the influence of complex plasma structures. These discoveries are important for understanding the physical processes occurring in thunderclouds, and can also be used in technological developments.
Scientists plan to study the influence of other electrode configurations and environmental parameters, as well as increase the temporal resolution of measurements. These studies can be used not only in atmospheric physics, but also in plasma technologies.
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