1. The Next Generation Weapon ???
EM BOMB
The Next Generation Weapon ???
PARTH MEHTA
07EC441

2. Modern World is a Battlefront…
Present era can be classified as an era of Technology, era of computers or age of industries.
But in history it will be surely classified as an era of WAR and Terrorism
In modern world its impossible for any country to remain aloof from wars however peaceful and non violent it may claim to be.
Be it for progress or on ethical grounds, be it invasive or defensive but war is inevitable.
And if a nation has to be indulged in war the only necessity is to win or at least be able to protect itself from invasion.

3. The efficient execution of a war campaign against a modern industrial or post-industrial opponent will require the use of specialized tools designed to destroy or disrupt information systems, Power Supply Systems And Major Industries of opponents.
In case of a War situation between a highly advanced nation and a technologically backward nation it becomes all the more necessary and unavoidable to use such means which are technologically and economically feasible yet highly devastating.
Today the technical and intellectual progress of mankind has presented us with many such weapons one of the most important of which is
EM BOMB

4. WHAT IS AN EM BOMB???
An electromagnetic bomb or E-bomb is a weapon designed to disable electronics with an electromagnetic pulse (EMP) that can couple with electrical/electronic systems to produce damaging current and voltage surges by electromagnetic induction.

5. HISTORY
The theory behind the E-bomb was proposed in 1925 by physicist Arthur H. Compton — not to build weapons, but to study atoms. 
Compton demonstrated that firing a stream of highly energetic photons into atoms that have a low atomic number causes them to eject a stream of electrons. 
Physics students know this phenomenon as the Compton Effect. 
The resulting electromagnetic pulse induced intense electrical currents in conductive materials over a wide area.

7. The electromagnetic pulse was first observed during high-altitude nuclear weapon detonations.
Ironically, this nuclear research led to an unexpected demonstration of the power of the Compton Effect, and spawned a new type of weapon.
In 1958, nuclear weapons designers ignited hydrogen bombs high over the Pacific Ocean. 
The detonations created bursts of gamma rays that, upon striking the oxygen and nitrogen in the atmosphere, released a tsunami of electrons that spread for hundreds of miles. 
Street lights were blown out in Hawaii and radio navigation was disrupted for 18 hours, as far away as Australia.

8. The US Army Corps of Engineers issued a publicly available pamphlet in the late 1990s that discusses in detail how to harden a facility against "HEMP” - high frequency electromagnetic pulse.
According to some reports, the U.S. Navy used experimental E-bombs during the 1991 Gulf War.
These bombs utilized warheads that converted the energy of conventional explosives into a pulse of radio energy.
It describes how water pipes, antennas, electrical lines, and windows allow EMP to enter a building.

9. The Soviet Union conducted significant research into producing nuclear weapons specially designed for upper atmospheric detonations, a decision that was later followed by the United States and the United Kingdom.
Though only the Soviets ultimately produced any significant quantity of such warheads.
But the most of them were disarmed following the Reagan-era arms talks.
CBS News also reported that the U.S. dropped an E-bomb on Iraqi TV during the 2003 invasion of Iraq, though this has not been confirmed.
Its Doubtless that EMP-specialized nuclear weapon designs belong to the third generation of nuclear weapons

10. The Basic Principle.
The basic principle is characterized by the production of a very short but intense electromagnetic pulse, which propagates away from its source with ever diminishing intensity, governed by the theory of electromagnetism. The Electromagnetic Pulse is in effect an electromagnetic shock wave.
Small nuclear weapons detonated at high altitudes can produce a strong enough signal to disrupt or damage electronics many miles from the locus of the explosion.
During a nuclear EMP, the magnetic flux lines of the Earth alter the dispersion of energy so that it radiates very little to the North, but spreads out East, West, and South of the blast

11. The signal is divided into several time components, and can result in thousands of volts per meter of electromagnetic energy ranging from extreme negative to extreme positive polarities. This energy can travel long distances on power lines and through the air.
This pulse of energy produces a powerful electromagnetic field, particularly within the vicinity of the weapon burst.
The field can be sufficiently strong to produce short lived transient voltages of thousands of Volts on exposed electrical conductors, such as wires, or conductive tracks on printed circuit boards, where exposed.

12. This aspect of the EMP effect is of military significance, as it can result in irreversible damage to a wide range of electrical and electronic equipment, particularly computers and radio or radar receivers.
Subject to the electromagnetic hardness of the electronic equipment, a measure of the equipment's resilience to this effect, and the intensity of the field produced by the weapon, the equipment can be irreversibly damaged or in effect electrically destroyed.
The damage inflicted is not unlike that experienced through exposure to close proximity lightning strikes, and may require complete replacement of the equipment, or at least substantial portions thereof.

13. What is inside the EM-Bomb?
EM Bomb Basically consists of one of the following
Flux Compression Generators (FCG)
Explosive or propellant driven Magneto-Hydrodynamic (MHD) generators
A range of HPM devices, the foremost of which is the Virtual Cathode Oscillator or Vircator.

14. The FCG was first demonstrated by Clarence Fowler at Los Alamos National Laboratories in the late fifties.
The FCG is a device capable of producing electrical energies of tens of Mega Joules in tens to hundreds of microseconds of time, in a relatively compact package.
With peak power levels of the order of Terawatts to tens of Terawatts, FCGs may be used directly, or as one shot pulse power supplies for microwave tubes.
The current produced by a large FCG is between ten to a thousand times greater than that produced by a typical lightning stroke

15. The central idea behind the construction of FCGs is that of using a fast explosive to rapidly compress a magnetic field, transferring much energy from the explosive into the magnetic field.
The initial magnetic field in the FCG prior to explosive initiation is produced by a start current supplied by an external source, such a a high voltage capacitor bank , a smaller FCG or an MHD device.
In principle, any device capable of producing a pulse of electrical current of the order of tens of kilo Amperes to Mega Amperes will be suitable.
A number of geometrical configurations for FCGs have been published
The most commonly used arrangement is that of the coaxial FCG.

18. Explosive and Propellant Driven MHD Generators
The fundamental principle behind the design of MHD devices is that a conductor moving through a magnetic field will produce an electrical current transverse to the direction of the field and the conductor motion.
In an explosive or propellant driven MHD device, the conductor is a plasma of ionised explosive or propellant gas, which travels through the magnetic field.
Technical issues such as the size and weight of magnetic field generating devices required for the operation of MHD generators suggest that MHD devices will play a minor role in the near term.

19. High Power Microwave Sources - The Vircator
The fundamental idea behind the Vircator is that of accelerating a high current electron beam against a mesh (or foil) anode.
Many electrons will pass through the anode, forming a bubble of space charge behind the anode
Under the proper conditions, this space charge region will oscillate at microwave frequencies. If the space charge region is placed into a resonant cavity which is appropriately tuned, very high peak powers may be achieved.

20. Conventional microwave engineering techniques may then be used to extract microwave power from the resonant cavity.
Power levels achieved in Vircator experiments range from 170 kilowatts to 40 Gig Watts over frequencies spanning the decimeter and centimetric bands.
The two most commonly described configurations for the Vircator are the Axial Vircator (AV) , and the Transverse Vircator (TV) .
The Axial Vircator is the simplest by design, and has generally produced the best power output in experiments.

21. An axial Vircator is shown in the figure.
Technical issues in Vircator design are output pulse duration, which is typically of the order of a microsecond and is limited by anode melting, stability of oscillation frequency, often compromised by cavity mode hopping, conversion efficiency and total power output.
Coupling power efficiently from the Vircator cavity in modes suitable for a chosen antenna type may also be an issue, given the high power levels involved and thus the potential for electrical breakdown in insulators.
An axial Vircator is shown in the figure.

24. Non-Nuclear EM BOMBS
This sort of e-bomb has a fairly simple, potentially inexpensive design, illustrated below.
The bomb consists of a metal cylinder (called the armature), which is surrounded by a coil of wire (the stator winding).
The armature cylinder is filled with high explosive, and a sturdy jacket surrounds the entire device. The stator winding and the armature cylinder are separated by empty space. The bomb also has a power source, such as a bank of capacitors, which can be connected to the stator.

25. Here's the sequence of events when the bomb goes off:
A switch connects the capacitors to the stator, sending an electrical current through the wires. This generates an intense magnetic field.
A fuze mechanism ignites the explosive material. The explosion travels as a wave through the middle of the armature cylinder.
As the explosion makes its way through the cylinder, the cylinder comes in contact with the stator winding. This creates a short circuit, cutting the stator off from its power supply.
The moving short circuit compresses the magnetic field, generating an intense electromagnetic burst.

28. It is a Non Lethal Weapon..
Generally considered 'non-lethal weapons', these weapons are not directly responsible for the loss of lives .
But the electromagnetic weaponry do however pose health threats to humans.
Affects the human central nervous system resulting in physical pain, difficulty in breathing, vertigo, nausea, disorientation, or other systemic discomfort.

29. Light and repetitive visual signals can induce epileptic seizures
Light and repetitive visual signals can induce epileptic seizures.Vection and motion sickness can also occur.
Cavitation, which affects gas nuclei in human tissue, and heating can result from exposure to ultrasound.
Microwave pulses can also affect the epidermis generating a burn from as far as 700 yards

30. Electronic Attack
Electronic attack involves the use of the EM energy, or anti-radiation weapons to attack personnel, facilitites, or equipment with the intent of degrading, neutralizing, or destroying enemy combat capability.
EA include communcations jamming, IADS suppression, DE/LASER attack, expendable decoys (e.g., flares and chaff), and counter radio controlled improvised explosive device

31. In modern warfare, the various levels of attack could accomplish a number of important combat missions without racking up many casualties. For example, an e-bomb could effectively neutralize:
Vehicle control systems
Targeting systems, on the ground and on missiles and bombs
Communications systems
Navigation systems
Long and short-range sensor systems

32. The modern research has taken EM weapons to such limits that they can easily ruin even the satellites orbiting around the earth.
What is worse is that presently research is in progress in order to control the satellites of opponents for our use or to misguide them.
As with modern military aircraft, naval surface combatants are fitted with a substantial volume of electronic equipment, performing similar functions in detecting and engaging targets and warning of attack.
They are vulnerable to electromagnetic attack, if not suitably hardened.
Should they be hardened, volumetric, weight and cost penalties will be incurred.

33. EMP weapons could be especially useful in an invasion of Iraq, because a pulse might effectively neutralize underground bunkers. Most of Iraq's underground bunkers are hard to reach with conventional bombs and missiles
A nuclear blast could effectively demolish many of these bunkers, but this would destroy the surrounding areas.
An electromagnetic pulse could pass through the ground, knocking out the bunker's lights, ventilation systems, communications -- even electric doors. The bunker would be completely uninhabitable.
While EMP weapons are generally considered non-lethal, they could easily kill people if they were directed towards particular targets. If an EMP knocked out a hospital's electricity, for example, any patient on life support would die immediately

34. The Delivery of Conventional Electromagnetic Bombs
The height of delivery of an EM BOMB by an aircraft depends on the type of activation, damage estimated and weight of the BOMB.
The figure shows two different launch profiles for GPS/Inertial guided weapons.
Fusing could be provided by a radar altimeter fuse to airburst the bomb, a barometric fuse or in GPS/inertial guided bombs, the navigation system.
The warhead fraction could be as high as 85%, with most of the usable mass occupied by the electromagnetic device and its supporting hardware

36. Lethal Radius Depends on Frequency of Operation

39. Defense against EM Bomb
The most effective method is to wholly contain the equipment in an electrically conductive enclosure, termed a FARADAY CAGE, which prevents the electromagnetic field from gaining access to the protected equipment.
It harmlessly routes the signal around the electronics inside, but the conductors inside must be insulated from spurious currents that are induced as the signal passes around the surface of the cage
However most such equipment must communicate with and be fed with power from the outside world, and this can provide entry points via which electrical transients may enter the enclosure and effect damage

40. While optical fibers address this requirement for transferring data in and out, electrical power feeds remain an ongoing vulnerability.
Hardened buildings employ the use of special EM gasketing on doors, special attention to conductive surfaces on the outside, and optical isolators on antennas.
The electrical supply to a hardened building must be located at a surprising depth underground in order not to "couple" with the signal, and if the electrical supply is connected to a standard power grid, the EMP will send a large surge (large enough to burn out lightning arrestors) into the power supplies of sensitive electronics.

42. Limitations Of EM BOMB Limited Range.
Thermionic technology ( vacuum tube equipment) more resilient to the electromagnetic weapons effects than solid state devices.
Radiating targets such as radars or communications equipment may continue to radiate after an attack even though their receivers and data processing systems have been damaged or destroyed.

43. Conversely an opponent may shut down an emitter if attack is imminent and the absence of emissions means that the success or failure of the attack may not be immediately apparent.
EM absorption effect the HPM weapons to shorter radii than are ideally achievable in the K and L frequency bands.
Should the delivery error be of the order of the weapon's lethal radius for a given detonation altitude, lethality will be significantly diminished.
An inaccurately delivered weapon of large lethal radius may be unusable against a target should the likely collateral electrical damage be beyond acceptable limits

44. CONCLUSION…
In the blink of an eye, electromagnetic bombs could throw civilization back 200 years ; and terrorists can build them for only $400 ....