Author: Huang Ruixin, Wu Haowei, Yu Kaiyi
In recent years, various science fiction movies have been on the air, and plasma has entered the public eye as a well-deserved "star" among them. In film and television works, he is not only a necessity for the manufacture of superweapons, but also a "great hero" to save mankind and provide energy. Although the movie is science fiction, plasma is indeed a real objective existence, and plasma does have a certain "magic" that surpasses traditional thinking. As a special medium, the electromagnetic parameters of plasma are mainly determined by its electron density and collision frequency, and under different parameter conditions, it can have different effects on the propagation of electromagnetic waves. Taking advantage of this unique electromagnetic property, applications in the military field include plasma antennas and plasma stealth. It can be seen that plasma technology has a high application value in the military. Now, let's unravel its mysteries.
Preparation of plasma
Plasma, also known as "plasma" or "plasma", is an electrically neutral aggregate composed of a large number of charged particles such as positive ions, negative ions, electrons, free radicals and various active groups. Since the total amount of positive and negative charges in this "plasma" is equal, it is called "plasma". In the movie "The Wandering Earth", tens of thousands of earth engine nozzles emit blue-white strong light, forming giant pillars of light, which are high-temperature plasma streams generated under the physical conditions of high energy density formed by nuclear fusion.
There are far fewer plasmonic substances on Earth than solid, liquid, and gaseous substances, but in the universe, the situation is very different. Isoplasm is widely found in interstellar space, star interior, earth's ionosphere and other natural environments, and is the main form of material existence, accounting for more than 99% of the total amount of matter.
Although there is little plasma on Earth, it is easy to make artificially. Ordinary gases are irradiated with rays, heated to a high enough temperature, or strengthened by an electromagnetic field, so that the outer electrons of the gas atoms are separated from the atoms and become free electrons due to accelerated motion or force. In this way, the original neutral gas is ionized and becomes a uniform "plasma" composed of positively charged ions, negatively charged electrons, and partially unionized atoms, which is a plasma with equal positive and negative charges. For example, electrical reactions such as corona, glow, and arc, which are common in chemical, energy, materials, and metallurgy, produce plasma.
Extremely high compatibility with military performance
The excellent electromagnetic properties of plasma determine that it has extremely high application value, and its related technologies and processes are widely used in lighting, display, medical, spraying, communication and semiconductor device manufacturing industries. In the field of national defense and military, it has great application prospects, and is even an important national defense resource.
Due to the unique physical properties of plasma, plasma antennas have a number of advantages over metal antennas:
Stealth traits. When the antenna is closed, the plasma antenna system will have almost no metal parts, the radar scattering cross section will be small, stealth in electronic warfare will be achieved, survivability will be increased.
Reduce mutual coupling. In the array antenna, there is almost no mutual coupling between the non-working unit and the working unit, which greatly reduces the interference between the array units and improves the performance of the antenna.
Electrical control of radiating components. There is no need to change the physical structure of the antenna, and the parameters such as frequency, bandwidth and directivity of the antenna can be dynamically reconstructed by changing the physical parameters such as the gas composition and electron concentration of the plasma, and the electronic control of the antenna is realized.
Solve the problem of high power. The use of high-voltage pulsed plasma antenna can solve the high-power problem in the current microwave antenna design, and avoid the situation of high-voltage burning of feeders and antennas.
Exquisite structure. The discharge tube in the antenna can be a quartz glass tube with high strength, and compared with the metal antenna, the weight of the glass products is lighter, the volume is smaller, and the assembly efficiency is improved.
The future is promising
With the rapid development of plasma technology, there are gradually many new plasma spraying technologies, the main types of plasma spraying technology, according to the different ionization media can be divided into two categories of liquid stability and gas stability plasma spraying, of which gas stabilized plasma spraying includes three methods: low-pressure plasma spraying, shielding gas plasma spraying and atmospheric plasma spraying. Liquid-stabilized plasma spraying includes two methods: water-stabilized and other liquid-stabilized plasma spraying. In addition to the above common advantages, these different types of plasma spraying technologies have their own unique advantages.
In terms of military applications, plasma spraying is mainly used in the field of anti-corrosion on ships, heat resistance and anti-erosion coatings for aerospace equipment, etc.
Low-pressure plasma spraying-thin coating technology (LPPS-TF) has low pressure and can realize the deposition of liquid phase solid phase and vapor phase solid phase, which has great application prospects in the preparation of new thermal barrier coatings (TBC), solid oxide fuel cell electrode and electrolyte coatings, hybrid conductor oxygen permeable films, and semiconductor device insulation (conductive) coatings.
Plasma spraying technology is widely used in traditional fields such as wear-resistant coatings and corrosion-resistant coatings, and its application fields have expanded from aviation and aerospace to the steel industry, automobile manufacturing, petrochemical industry, textile machinery, shipbuilding and other fields. In recent years, the application research of plasma spraying technology in high-tech fields such as nano-coating materials, gradient functional materials, superconducting coatings, biological functional coatings, etc., has gradually attracted people's attention and entered a new stage of development.
In today's development of modern warfare and the layout of future science and technology, plasma technology will undoubtedly become a key technology with wide application and important strategic location, not only in daily use, but also in military application is also worthy of our continuous attention.