## 1 Introduction  
Nowadays, electromagnetism is a vital science in generating mechanical forces and torques to propel vehicles and satellites to space and transportation on Earth. It rapidly accelerates ferromagnetic projectiles using electrical energy converted to kinetic energy. Electromagnetic science has contributed to many applications, such as Earth-to-orbit (ETO) microsatellite systems [1]; powerful launchers that can propel small satellites to settle at low Earth orbit [2]; low-speed and high-speed trains, high-speed, long-range fire support naval guns, and direct satellite launch to space [3]; launch of lunar liquid oxygen (LLOX) from the Moon to the stationary Lagrangian point L2 [4]; and electromagnetic guns [5, 6, 7, 8, 9, 10, 11, 12]. A coil-gun launcher is an obvious application for electromagnetic systems. Such an application is used to launch a ferromagnetic projectile with very high velocities for long distances, as described in [13]. For coil guns only, accelerating stages can be cascaded to boost the projectile speed more and more. A distinctive advantage of the coil gun over other launchers is it can electromagnetically stop and recover the projectile before leaving the barrel. Moreover, the launching process results in no damage, therefore the equipment lasts for an endless time. In addition, the cost of this kind of gun is relatively low comparedto traditional rockets as it is recyclable, never causes environmental pollution, and has low electricity consumption. Space exploration, especially Moon exploration, requires improvement of launching capabilities. The Moon's soil is rich in oxygen and metals used for refueling space rockets in space. To launch things (including extracted oxygen and metals) from the Moon to space, solar-based electromagnetic launchers may be the most appropriate solution [14; 15]. This demand requires analysis and innovation of electromagnetic launchers (EMLs) which will be utilized for rocket launching from the Moon without fuel. In addition to Moon exploration, launching nanosatellites (CubeSat) from space vehicles is an important part of modern space exploration. Therefore, electromagnetic launcher development attracts great interest to meet space requirements. Even though the electromagnetic launcher has no restriction on the speed limit, experimental studies are performed with low launching speeds for security. Experiments demonstrated that the launching mass and energy are extendable [16]. There are some drawbacks to this kind of launcher. 1. The launcher's low efficiency is a challenging drawback, requiring effort to enhance the launcher's efficiency. 2. Many stages must be used to accelerate the projectile to ultra-high speed, making the launcher extremely long. For instance, Sandia researchers [4] designed very long barrels and solenoids to increase the projectile's velocity. They built a 960 m long launcher that launched a package carrying a 600 kg satellite and a 1220 kg boost rocket for orbital insertion with 2000 gees. And in [6], a NASA Langley coil cannon was created to accelerate massive beams to hypervelocity. 3. Moreover, this kind of launcher cannot direct propel non-magnetic metals. In [17], a four-stage coil gun was developed to propel non-magnetic materials. They had to rapidly push the projectile before accelerating it with the developed gun. There are some limitations to achieve 100% efficiency:  
1. High magnetic reluctance which limits the number of flux lines and makes the user increase the current passes through the coil to achieve a certain number of flux lines. 2. The current that passes through the coil is extremely high which requires high-power expensive electronic devices. 3. Low saturation flux density of all ferromagnetic materials used for projectile manufacturing is a huge challenge. 4. Launcher coil electrical resistance which consumes a considerable amount of energy. 5. Eddy current is produced inside the projectile due to the presence of changing flux which will generate a backward force. 6.