According to the report of Nihon Keizai Shimbun on April 22, the electromagnetic gun development plan of the Japan Defense Equipment Agency has entered the second phase. Although common in science fiction novels, this weapon has not yet been put into practical use. The Department of Defense and Equipment stated that although it has not yet reached the level of being able to be installed, electromagnetic guns have attracted much attention and hope to be put into use as soon as possible. The report states that electromagnetic guns are weapons that use electromagnetic fields to launch shells. It can provide a firing speed that traditional artillery propelled by gunpowder cannot achieve, and countries are vigorously developing it. Up to now, the Defense Equipment Agency has been focusing on how to accelerate shells to respond to hypersonic missiles. However, current electromagnetic cannons require charging after firing each shell, making them unable to exert their corresponding power in actual combat. The government has therefore allocated 16 billion yen (approximately 100 million US dollars) in the 2023 budget for the development of continuous firing technology for electromagnetic guns, which is said to take 4 to 5 years. The main advantages of electromagnetic guns include: being able to achieve hypersonic speeds compared to traditional weapons; Because electric acceleration is used, the muzzle velocity can be easily adjusted; The shell size is small and difficult to detect and intercept; The cost is much lower than guided missiles. Based on the above advantages, electromagnetic guns are expected to demonstrate their power in defending against hypersonic missiles that opponents have already installed or are vigorously developing. The so-called hypersonic missile mainly refers to a missile with a speed exceeding Mach 5, capable of flying for a long time in a low orbit below the normal orbit, and can change its speed and altitude at any point in time. Due to its ability to break through existing air defense networks, countries around the world are urgently taking measures. The Department of Defense Equipment began developing electromagnetic acceleration systems in 2016, and by 2021, medium-sized electromagnetic guns with a caliber of 40mm had been produced. Its goal is to achieve a muzzle velocity of over 2000 meters per second, and it is currently capable of firing a projectile with a mass of about 320 grams at a muzzle velocity of 2297 meters per second. The shooting test conducted in October 2023 confirmed the flight stability and power of the Japanese electromagnetic gun. Although details have not been disclosed, it is reported that the shell penetrated two or more layers of steel plates used to simulate the ship. In August 2023, Japan conducted its first global sea test launch. With the cooperation of the Maritime Self Defense Force, the R&D team installed electromagnetic guns on the actual ship and collected launch data. According to the report, one of the challenges that electromagnetic cannons need to overcome is that the heat and friction generated during projectile acceleration can cause damage to the internal trajectory. The shell accelerates to over 2000 meters per second within a few milliseconds, with a huge acceleration that is not on the same order of magnitude as traditional howitzers. Reducing the size of the power supply is also a major challenge. The power supply for a 40mm caliber electromagnetic gun is the size of four containers. In the future, whether electromagnetic guns are deployed on ships or on the ground, customized development needs to be carried out for their platforms, and miniaturization of power supply is an indispensable element. The Defense Equipment Department stated that it hopes to use civilian technology to promote the miniaturization of power sources, and looks forward to developing high-energy density batteries and more high-voltage resistant power control devices. (Lai Xin She)