Today's man-made powerful electromagnetic pulse method - high-altitude nuclear explosion!

In addition to the familiar effects of shock waves, optical radiation, early nuclear radiation and radioactive contamination, nuclear explosions also produce electromagnetic pulse effects. This electromagnetic pulse has no harmful effect on the human body, but it can cause serious damage to the electronic components of weapons. In this regard, people began to pay less attention to its destructiveness. It was not until the early 60s, when the United States and the Soviet Union successively conducted nuclear tests at high altitudes, that they had a real understanding of it.

In July 1962, the United States exploded a 1.4 million ton TNT equivalent hydrogen bomb 400 kilometers above Johnston Island in the Pacific Ocean. After the explosion, on the island of Oahu, Hawaii, 14,000 kilometers away from the center of the explosion, the street lights on more than 300 large and small roads suddenly went out, and hundreds of burglar alarms sounded at the same time. People have been studying it for almost 20 years. Only then did the mystery of the above strange phenomenon be completely revealed. It turns out that the "perpetrators" who blinded the street lamp and alarmed the burglar alarm were both nuclear electromagnetic pulses.

The so-called electromagnetic pulse is an instantaneous change in the electric and magnetic fields. Figuratively speaking, an electromagnetic pulse is like an electromagnetic signal generated by lightning during a thunderstorm. The strong electromagnetic pulse produced during a nuclear explosion is called a nuclear electromagnetic pulse.

The physical cause of the nuclear electromagnetic pulse is that when the rays released during a nuclear explosion collide with air molecules at the speed of light, the high-energy rays collide electrons out of the air molecules and cause the electrons to spread outward rapidly

According to the law of conservation of momentum and energy in the theory of relativity. The positively charged parent particles (air molecules) move at a lower speed and change the direction of motion. In physics, this separation of positive and negative charges is the Compton effect. Since this separation of positive and negative charges occurs on a large scale, an ionized region is formed around the blast center. This region is called the source area, and the strong electric field generated in the source region is called the source field. Negatively charged electrons have a smaller mass, and they fly away from the center of the explosion at a speed of approximate light speed; The parent particles that have lost electrons are more massive and less velocity-specific than electrons, so they still gather around the center of the explosion. The sharp separation of positive and negative charges results in a positive charge at the center of the explosion and a negative charge at the distance. Therefore, the direction of the field strength of the source field is outward from the center of explosion.

When a nuclear explosion occurs at an altitude of 3-25 km, the electric field formed by the separation of charges will be radial, since the rays are emitted uniformly in all directions. It has the same intensity in all directions from the center of the explosion outward. That is, the spherical symmetry of the source area, and because the rays are rapidly absorbed by the low-altitude dense atmosphere, the radius of the source area is only 2~8 kilometers, so the outward radiation energy is very small. Theoretically, in the area outside the radius, the effect produced by the opposite direction of the symmetry is completely canceled out, which has little damaging effect on the electronics on the ground. In fact, due to various circumstances, it is inevitable that there will be asymmetry in the source region, so there will be a certain amount of Compton electrons flying from the center of the explosion, generating a net electron current, which in turn will produce a magnetic field, and the change of the magnetic field will cause a change in the electric field. This change in the electromagnetic field forms an electromagnetic pulse, which will have a certain impact on the electronic equipment on the ground.

When a nuclear explosion occurs on or near the ground. The apparent asymmetrical shape of the source zone in contact with the ground results in the formation of a strong radiated electromagnetic field, which is destructive over a range of about 15 km, which is approximately equal to the maximum distance of other effects produced by a nuclear explosion.

When a nuclear explosion occurs at an altitude of more than 30 km with thin air, it can penetrate a longer distance due to the slower attenuation of the rays. As a result, the destructive effect of the nuclear electromagnetic pulse can reach thousands of kilometers.

Compared with the lightning, radio waves, and radar waves that we are familiar with, the nuclear electromagnetic pulse has the following characteristics, although the electromagnetic waves are generated by alternating changes in the electric field and the magnetic field

(1) Large amplitude. The electric field strength of the nuclear electromagnetic pulse can reach 1-100,000 volts/meter in a range of several kilometers, which is millions of times that of the electromagnetic field of radio waves. It is thousands of times more powerful than high-power radar waves.

(2) Short action time. The electric field of the nuclear electromagnetic pulse changes rapidly, rising to its maximum value in 0.01 --- 0.03 microseconds, and only tens of microseconds from occurrence to finish, which is 50 times faster than lightning.

(3) Spectrum width. The wide frequency range of the nuclear electromagnetic pulse (from a few hertz to 100 MHz) encompasses almost all the frequency bands used by modern military electronic equipment, so it has a greater impact on military electronic equipment.

(4) Wide range of action. Although the source field of the electromagnetic pulse generated by a low-altitude nuclear explosion is only a few kilometers, the radiated electromagnetic pulse signal can be transmitted to a long distance. The electromagnetic pulse from a high-altitude nuclear explosion has a wider range of effects. Some people estimate that if a 50-million-ton nuclear warhead is exploded 320 kilometers from space in Nebraska, the United States will produce a field strength of 50,000 volts per meter, and the electromagnetic pulse radiated will turn the whole United States into "pitch black."

With the development of electronic technology. Semiconductor devices and integrated circuits are becoming more common in a variety of weapon systems. Therefore, the nuclear electromagnetic pulse has a destructive effect on modern weapons that cannot be underestimated. The electromagnetic pulse generated by a nuclear explosion can enter the interior of electronic equipment through antennas, cable connections, metal pipes, etc., and generate induced currents, causing serious damage to electronic equipment. The destructive effects of nuclear electromagnetic pulses on electronic devices can generally be divided into two categories: functional damage and operational interference. Functional damage refers to the breakdown of the insulating material of the cable or the permanent damage caused by the action of nuclear electromagnetic pulse on some components of the electronic equipment. Nuclear electromagnetic pulses are more destructive to semiconductor devices. Because it only takes one thousandth to a few hundredths of a joule of energy to burn out a transistor. Although the nuclear electromagnetic pulse is short-lived, the damage to the function of electronic equipment wiring and electronic components is permanent. If the insulation material of the cable is broken down and causes a short circuit, a large number of postal communication systems such as telephones and telegraphs and military communication systems will be interrupted. In particular, if the main control equipment is damaged, it will cause chaos in the entire control system. Serious consequences. Electronic equipment in military systems, such as aircraft, missiles, ships, and air defense weapons, will cause heavy losses if they are damaged by the nuclear electromagnetic pulse. Operating interference refers to the introduction of additional signals that change the working state of some devices, causing the electronic equipment to malfunction, emit false signals, or eliminate and change the contents of the memory, although the nuclear electromagnetic pulse does not damage the system or device. For example, after a megaton nuclear bomb explodes in the air, a missile that is on standby can no longer be launched as instructed because the information stored in the computer on the bomb has been cleaned. For this reason, some military experts call the nuclear electromagnetic pulse "the nemesis of the electronic components of weapons" and "the ultimate means of electronic countermeasures."