As a defensive weapon in modern warfare, the reactive armor of tanks can quickly respond to attacks from anti tank weapons, effectively reducing or avoiding damage to the tank's main armor. The reactive armor currently used by countries around the world is usually "explosive reactive armor". The working principle of "explosive reactive armor" is to detonate insensitive explosives at the moment when the tank is hit, causing the steel plates installed in front and behind the armor to be pushed out in the opposite direction at extremely high speed, thereby interfering with the jet of armor piercing bullets or causing the body of the long rod armor piercing bullet to break, achieving the purpose of protecting the main armor. This design of "using explosion to counter violence" can be called a stroke of genius, but it is also a double-edged sword in itself. The shock wave generated by the explosion may damage the tank's own sighting equipment, and even pose a threat to accompanying infantry. After one detonation, the armor plate becomes ineffective and cannot withstand continuous attacks. With the advancement of technology, a more sophisticated, quiet, and effective armor defense technology is emerging: non explosive reactive armor. It abandons the traditional roar and smoke of explosions, and reinterprets a silent defense story with the silent and rapid laws of physics. The core design concept of non explosive reactive armor is to use high-speed physical motion to achieve defense, without relying on chemical explosions. Electromagnetic armor is a typical representative of non explosive reactive armor. Electromagnetic armor is usually composed of two layers of conductive plates sandwiching a layer of insulating material and connected to a supercapacitor bank. When the metal jet of the armor piercing bomb penetrates the outer steel plate and enters the insulation layer, it instantly forms a closed circuit. At this point, the enormous electrical energy stored in the capacitor is released in nanoseconds, generating millions of amperes of instantaneous current. This current flows through a metal jet, forming a strong magnetic field that can cause severe disturbance to the jet, tearing it apart or even vaporizing it, thereby losing its penetration ability. For example, the UK once showcased the "Warrior" infantry fighting vehicle test vehicle equipped with electromagnetic armor, which consists of bulletproof metal plates, insulation plates, power distribution lines, and other components. When an anti tank rocket hits electromagnetic armor, the circuit conducts to form a super strong current and electromagnetic field, which can disperse the metal jet of the rocket and protect the main armor from damage. The advantages of non explosive reactive armor are obvious. It eliminates the collateral damage and personnel risks to its own equipment, and after reaction, the armor module can often maintain structural integrity and even have a certain degree of multiple defense capabilities. More importantly, it opens a door to lighter, smarter, and more adaptive armor systems. In the future, combined with advanced sensor networks, this armor may be able to accurately mobilize defense modules in specific areas to respond upon detecting threat types and incoming directions. However, non explosive reactive armor also faces some challenges. For example, electromagnetic armor requires a powerful energy storage and instantaneous discharge system, and its weight, volume, and energy management are challenges faced by researchers. From the working principle of non explosive reactive armor, we can feel that armor defense technology is not only a simple and cumbersome way to withstand the force of shells, but also an agile, precise, and ingenious physical game. The next time I see the agile figure of a tank, perhaps I can imagine that beneath its silent armor, there is a silent protective storm based on profound physical laws surging. (New Society)