Electromagnetic energy is determined to be a potentially dangerous weapon for national security. It can be produced in pulse form through two traditional methods: nuclear explosions in the air and microwave radiation. High-altitude electromagnetic pulse (HEMP) is an almost instantaneous electromagnetic energy field generated in the atmosphere by the energy and radiation of a nuclear explosion. It can damage electronic equipment in a very large range, depending on the power of the nuclear equipment and the height of the explosion. High-power microwave (HPM) electromagnetic energy can be generated in almost instantaneous pulses generated by special electronic devices that convert battery energy or strong chemical reactions or explosions into strong microwaves, but are very harmful to electronic devices, but it only ranges within smaller areas. In addition, although HEMP weapons are large in scale and require nuclear capabilities and high-altitude rocket launch technology, HPM weapons are smaller, can contain much lower technology, and may be lighter within some groups of extremist people’s capabilities. HPM can damage a computer like HEMP, although its scope of infliction is much smaller.
What is High-Altitude Electromagnetic Pulse (HEMP)?
HEMP occurs when a nuclear weapon explodes at a high altitude on the surface of the earth. The gamma rays generated interact with the atmosphere and produce an instantaneous strong electromagnetic energy field. If it radiates outwards, it is harmless to humans, but it will overload computer circuits. Similarly, but the speed of damage is much faster than lightning. In 1962, during the high-altitude nuclear test (code-named “Starfish Prime”) over the Pacific Ocean, radio and electronic equipment in parts of Hawaii were destroyed. The impact of HEMP is widely known in the United States. The HEMP effect can span thousands of miles (a single device detonated at a reasonable height over Kansas may affect any continent in the United States) and can be intercepted by pilots, depending on the height, structure, and intensity of the nuclear explosion. Metals, such as cables or overhead wires, are used as antennas to transmit energy shock waves to electronic systems in automobiles, airplanes, or communication equipment.
High-altitude nuclear explosions (generating HEMP) will produce three main energy components, which occur in sequence and have distinct effects that can collectively damage electronic equipment. The first component of energy is the initial shock wave of energy, lasting as long as 1 microsecond, similar to extremely strong static electricity, which can overload the circuit of any electronic device within the sight of the explosion. Then there is the secondary energy component, which has properties similar to lightning. If anti-lightning protection measures are in place, the second energy component will not cause problems for some equipment in critical infrastructure. However, the rise time of the first component is so fast and intense that it can destroy many defenses, allowing the second component to move and further disrupt the operation of electronic equipment.
The third energy component is the longer magnetohydrodynamic (MHD) signal, which lasts from about 1 microsecond to a few seconds. This late pulse or geomagnetic signal will cause major damage to longline electronic equipment.
In the third pulse of later energy, there are two components called “blast” and “heave” by experts. The “explosion” is the result of an expanding, fully conductive fireball that distorts the Earth’s magnetic field lines. “Heave” occurs by heating and ionizing parts of the atmosphere directly below the ascending bomb, and because it is conductive, it also distorts the earth’s magnetic field. Both are considered MHD signals and are called “slow” signals because they depend on the dynamics of expanding clouds or fireballs.
As the fireball expands, local magnetic effects accumulate underground along long power lines, and then quickly collapse, producing “late” MHD peak power, which overloads the connected equipment on the power grid and telecommunication infrastructure. This effect can amplify the initial HEMP effect, and systems connected to hierarchical power and communication systems may be further disturbed by the combined effect. Smaller isolation systems do not collect so much of the third energy component, so usually only interrupt the first energy component of HEMP.
It is also important to note that this last pulse depends on the total energy of the nuclear explosion and is therefore usually only related to higher power nuclear weapons. However, the energy of the first burst is a limited saturation effect, and it is produced by everyone, both low-power and high-power nuclear weapons.
What is High-Power Microwaves (HPM)?
Microwave is characterized by electromagnetic energy with a wavelength in the centimeter or millimeter range, and can be used for high-frequency communications or radar at medium power levels. Powerful microwaves can be generated as instantaneous electromagnetic pulses, for example when a powerful chemical explosion occurs, a special coil called a flux compression generator converts it into a strong electromagnetic field. Other methods can be used to make reusable HPM weapons, such as combining reactive chemicals or using powerful batteries and capacitors to generate EMP energy. It can be focused with a special-shaped antenna or radiator to achieve a HEMP-like effect in a limited space or a limited distance. However, unlike HEMP, HPM radiation uses shorter waveforms at higher frequencies, which makes it very effective for electronic devices and more difficult to cure. A simple mechanical device the size of a suitcase that uses chemical explosives and a special focusing antenna can theoretically generate instant HPM shock waves that can paralyze many computers within a mile (1.6 kilometers). With higher output (MW) and longer power supply, it may cause bodily harm to people near the emission source or who may be in the path of a narrow focused energy beam 0.22
Effects of EMP
Studies on the effects of electromagnetic energy used as weapons are rarely published or remained secret; however, it is well known that strong HEMP fields radiating outward can damage high-frequency circuits and immediately generate dangerous voltages and currents in electronic equipment thousands of kilometers away from the nuclear explosion. If the electronic device is connected to another metal (which can also be used as an antenna), the efficiency will increase. Due to the interconnection of infrastructure computer systems, the widespread HEMP effect may cause long-term grid and fuel distribution disruptions, transportation systems, food and water supplies, communications and equipment for hospitals and emergency personnels, and military communications systems with civilian infrastructure.
The HPM weapon has a shorter range than HEMP, but it can induce currents large enough to melt circuits or cause equipment to malfunction within minutes, days, or even weeks. A helicopter flying HPM weapons during a radar test in New York produced a weak burst of energy, which allegedly disrupted the Global Positioning System (GPS), and the passenger plane was used to land at the airport for two weeks, near Albany, New York.
A HEMP attack on the continent of United States may involve nuclear warheads with an equivalent of 1 megaton or less, using explosions hundreds of miles in the Midwestern states to hit computers on both sides of the coasts. However, to produce the HEMP effect in an area 250 miles in diameter (approximately the size of a battlefield), you may only need a low-height payload missile, which can be lifted by a relatively small nuclear device. The missile carrying the nuclear bomb was launched from the deck of a naval freighter. As a result, it is said that HEMP may render the computer unusable on large areas of the coast of the United States.
It is reported that the harmful effects of HEMP and HPM decrease as they move, and individual electronic devices are unlikely to be damaged. In order to maximize the coverage of HEMP, the nuclear device must explode at a very high place in the atmosphere, too far from the surface of the earth, and not directly cause injury or damage due to heat or explosion. In addition, the HEMP produced by a nuclear explosion is instantaneous, which is too short for the current flowing through the human body, so it has no effect on the human body. Microwave energy weapons (HPM) are smaller, closer to the intended target, and can sometimes be emitted for longer periods of time. These characteristics of HPM can sometimes cause painful burns or other trauma to people along the path of the focused energy beam. If people are too close to the microwave transmitter, it can even be fatal.
Both HEMP and HPM can permanently stop the vehicle through advanced electronic ignition and control systems; however, older electronic components such as vacuum tubes and induction coils used for spark ignition are generally stronger and more resistant to EMP. The circuit becomes smaller and more susceptible to electromagnetic interference. Therefore, countries with older technological infrastructures may be less susceptible to the adverse effects of HEMP or HPM than countries that rely on higher technological levels.