Now and The Future
As useful and revolutionary gunpowder and guns are, everything comes with its limitation - and it is part of the scientific method to improve and refine techniques as technology evolves. As our understanding of electromagnetism and optics improved, so did our weapons. This section explores two of the methods that have been considered and implemented in armies, both of which at the heart of their design utilise the principles of projectiles.
Information in these green boxes is considered advanced reading! Read this information if you want to learn more.
RAILGUNS
A railgun is a projectile launcher based on the principles of electromagnetism. In its usual form, it is composed of two rails with an armature attached to both which is free to slide along the rails with minimal friction. An armature is a current carrying conductor which is a key component of electro-mechanical machinery. In a rail gun, current flows along one rail, through the armature, and along the other rail from an external power source.
​
​
​
​
​
​
​
​
​
​
The primary benefit of a railgun is that it can utilise the laws of electromagnetism to impart more kinetic energy to bullets than other firearms. Even the latest military guns which use gunpowder and other explosives can only reach 2 km/s, compared to the 3 km/s that railguns can achieve. This makes them far more destructive, as the transfer more kinetic energy to a potential target and therefore any shot is more likely to be lethal. Moreover, railguns inevitably have greater range, so can hit a target from greater distance, obtaining maximum utility from the basic benefit of projectiles as weapons as explained in our introduction.
​
Secondary benefits include cost; railguns are much less expensive to create and use in mass quantities than conventional explosive guns. It is therefore beneficial for any cost-saving government to invest heavily in the production of railguns. Another secondary benefit is that it makes weapons far easier and safer to store and transport due to the absence of explosive material. This reduces the risk factor for governments operating with military overseas.
​
​
​
​
​
​
​
​
​
​
​
The railgun originates from a device known as an ‘electric cannon’, which was created by French entrepreneur Louis Octave Fauchon-Villeplee in 1918. He was later awarded a US patent so that he could develop it further. It was a very simplistic design, simply involving two busbars as the parallel rails and a magnetic field applied across the entire setup. This early form of the railguns was neither efficient nor powerful enough to be a viable weapon to be used in a military capacity.
​
Railguns were first proposed as an appropriate weapon in the second world war by the German military. However, the demands put forward by the Luftwaffe (German air force) were too great for the period, with the relevant designers unable to adhere to the 2km/s requisite muzzle velocity.
It wasn’t until less than ten years ago that a railgun was produced and tested which is ready for application to the military. The Naval forces of the United States of America put a railgun into testing which can reach speeds of 2.4 km/s with a 3.2kg projectile.
The mathematics of a railgun are heavily dependent on one of the key equations in electromagnetism; Faraday’s law. This is given below:
​
​
where ε is the electromotive force, N is the number of coils on a solenoid and â€‹Φ is the rate of change of flux linkage, dictated by the area drawn out by the spinning solenoid and the strength of the magnetic field applied perpendicular to the wire.
To calculate the magnetic field generated by the current running through the wires, we can use the Biot-Savart law, which tells us that the magnetic field between two infinitely long current carrying conductors is given by:
​
where μ0 is the permeability of free space, I is the current running through the wires (in this case our rails) and l is the perpendicular distance from the end of the rails.
If a uniform magnetic field is applied perpendicular to the axis of both the armature of length and the rails carrying current , then the force applied to the projectile is given by the following equation:
​
​
Therefore, to optimise the force on the armature, which will become the projectile in our railgun, we must consider which variables to change. Clearly from our calculations, increasing the current will increase the force, as will increasing the magnetic field strength. However, since the field strength is itself dependent on the current through the wires, they key variable to control in a railgun is the current given to the rails.
I
​
A directed energy weapon is a weapon emitting highly focused energy to damage the target which it is aimed at. They can be used in warfare in both an offensive and defensive capacity; with applications in the disabling of opposition weaponry as well as being used in electrolasers and dazzlers. Although not used in warfare, many of the following concepts are currently under development.
The primary advantage of Directed Energy Weapons (DEW) as projectiles is that the effect of gravity is almost negligible. Other than the very slight effect of gravitational lensing (the bending of light by a massive object to distort the electromagnetic radiation travelling between a source and an observer. However, over the distance that DEW’s are used on earth, the effect of gravitational lensing can be neglected.
​
A further advantage of DEW’s with respect to other projectiles is that they can be used with subtlety. This is because the electromagnetic radiation they use is often above the visible spectrum in terms of frequency, so can’t be seen.
DEW’s can be subcategorised into 4 types:
-
Microwave weapons
-
Electrolasers
-
Pulsed energy projectiles
-
Dazzlers
Microwave weapons
Included in microwave weapons are millimetre wave sources which heat the water in the targets blood and skin. This is often not lethal but causes the enemy so much pain that they are temporarily incapacitated.
​
​
​
​
​
​
​
​
There is also an air defence system known as Vigilant Eagle which aims high frequency EM radiation at anti-air missile-firing stations. This causes disturbance to the station’s land to air guidance system, such that it can no longer seek out and take down the aircraft. Therefore, in any warfare that is heavily air based nations will utilise the Vigilante Eagle system by pairing it with aircraft such as bombers or possible care packages for troops.
Electrolasers
Electrolasers provide energy to ionise a certain area of gas, before transmitting a high-energy electric current through the plasma which forms a resulting path. Therefore, it hits its target with a powerful electric current which can cause a multitude of problems to both machinery and humans.
Pulsed Energy Projectile (PEP)
PEPs are essentially guns which project EM radiation at their target. They do this by emitting radiation of the EM range which creates rapidly expanding plasma. The effect of this is to stun the enemy as a result of the pain and shock caused by the expanding plasma.
Dazzlers
The dazzler is a self-explanatory weapon, which blinds and disorientates its target so that they are again incapacitated, however temporarily. They can either be of the infrared variety for confusing sensors and other electronic detection devices, or visible light to briefly impair the vision of a human, though most dazzlers do not cause permanent damage to the eye.
​
DEW’s work in way that is very like lasers. The electrons in a source in the weapon are excited to a higher energy level by an electrical current generated by the DEW. When they return to their normal state, they emit photons of a particular wavelength. Due to the nature of the atom, electrons are only able to exist in discreet energy levels. Therefore when they de-excite they release photons of a particular energy and therefore a particular wavelength according to the relationship .
​
When is the first evidence of DEWs being used?
250 BC. Curiously, the use of DEWs can be traced back to Archimedes. Historians’ accounts state that as a fleet of Roman ships attempted to raid Syracuse, a burning mirror was used to set fire to the Roman boats. Archimedes did this by focusing the light from the sun on to the wood of the boats using a series of mirrors such that the intensity of the sun’s EM radiation caused them to be set alight.
On what other occasions have DEWs been used?
Star wars: The nickname ‘Star wars’ was coined in the 1980s when the Strategic Defense Initiative was proposed under Ronald Reagan. It was an initiative that promoted the possibility that intercontinental missiles could be sabotaged by lasers in orbit around the earth. This remains merely a concept however, as the project was discontinued before it could actually be used in war.
Iraq: Iraqi electronic systems were disrupted and sabotaged by UK and US forces in the Iraq war using Microwave weapons. This allowed British and American troops to be assured that they could attack certain areas without being detected by radar or attacked using weapons that rely on electronic systems.
​
When it comes to concluding our research, we are faced with the inevitable question; what has been the most significant technological breakthrough or invention with regard to the use of projectiles in warfare? One would assume that the ingenuity of Australopithecus (the first tool-bearing mammals) would make any shortlist. Notwithstanding this, it would be possible to disregard this as simply the starting point in a 2.5 million year development project of the human race. Furthermore, the use of projectiles precedes even humans, as primates of all varieties have been known to throw objects in certain circumstances.
​
So we then look at our criteria, what is considered ‘significant’ in warfare? Looking at the brutality across the ages it always seems that the success of a party is determined by the ease with which they can end the enemy’s life. Therefore, we must assume that the most significant development of projectiles is that which most easily ensure the death of a target. And there is one obvious candidate for that position; gunpowder.
​
Gunpowder was the invention that allowed something as heavy, unwieldy yet brutal as a bullet launch itself with unimaginable (at the time) velocity towards its target, penetrating flesh with total ease. However, the primary reason that it can claim to be the most significant invention is that gunpowder inevitably brought with it guns, which are one weapon that has survived the test of time such that it has been used in warfare since its invention in the 11th century to the present day.
​
​
CONCLUSION
DIRECTED ENERGY WEAPONS
