24-09-2014, 03:33 PM
E –BOMB
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INTRODUCTION
The electromagnetic bomb, or e-bomb, is a new class of weapon based on high-power surges, and it can render impotent even the
most advanced digital weapons. The first electromagnetic pulse effect was observed during a high altitude airburst nuclear
weapons testing (In July 1962, a 1.44 megaton United States nuclear test in space, 400 kilometres above the mid-Pacific Ocean,
called the Starfish Prime test Starfish Prime also made those effects known to the public by causing electrical damage in Hawaii,
about 1,445 kilometres away from the detonation point, knocking out about 300 streetlights, setting off numerous burglar alarms
and damaging a telephone company microwave link). In 1962, the Soviet Union also performed a series of three EMP-producing
nuclear tests in space over Kazakhstan, which were the last in the series called "The K Project".
The Electromagnetic Pulse is in effect an electromagnetic shock wave. 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 (i.e. kilovolts) on exposed electrical conductors, such as wires, or conductive tracks on printed
circuit boards, where exposed. It is this aspect of the EMP effect which 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.
II. THE TECHNOLOGY BASE FOR CONVENTIONAL ELECTROMAGNETIC BOMBS
Key technologies which are extant in the area are explosively pumped Flux Compression Generators (FCG), explosive or
propellant driven Magneto-Hydrodynamic (MHD) generators and a range of HPM devices, the foremost of which is the Virtual
Cathode Oscillator or Vircator. This paper will review the basic principles and attributes of these technologies, in relation to
bomb and warhead applications.
A. EXPLOSIVELY PUMPED FLUX COMPRESSION GENERATORS
An explosively pumped flux compression generator (EPFCG) is a device used to generate a high-power electromagnetic pulse by
compressing magnetic flux using high explosive. 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. An EPFCG
can be used only once as a pulsed power supply since the device is physically destroyed during operation. An EPFCG package
that could be easily carried by a person can produce pulses in the millions of amperes and tens of terawatts, exceeding the power
of a lightning strike by orders of magnitude. They require a starting current pulse to operate, usually supplied by capacitors.
EXPLOSIVE AND PROPELLANT DRIVEN MHD GENERATORS
The design of explosive and propellant driven Magneto-Hydrodynamic generators is a much less mature art that that of FCG
design. 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. In the context of this paper, their potential lies in
areas such as start current generation for FCG devices.
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. Current is
collected by electrodes which are in contact with the plasma jet.
HIGH POWER MICROWAVE SOURCES – THE VIRCATOR
The various microwave sources are : Klystron , Magnetrons, Gyrotrons, Vircators, Ubitron/Free-Electron Lasers, Klystronlike
Intense Relativistic Electron Beam Devices . The Vircator is of interest because it is a one shot device capable of producing a
very powerful single pulse of radiation, yet it is mechanically simple, small and robust, and can operate over a relatively broad
band of microwave frequencies.
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. Conventional microwave engineering techniques may then be
used to extract microwave power from the resonant cavity. Because the frequency of oscillation is dependent upon the electron
beam parameters, Vircators may be tuned or chirped in frequency, where the microwave cavity will support appropriate modes.
Power levels achieved in Vircator experiments range from 170 kiloWatts to 40 GigaWatts
THE DELIVERY OF CONVENTIONAL ELECTROMAGNETIC BOMBS
We could deliver an e-bomb in a number of ways: cruise missile, unmanned aerial vehicle, or aerial bomb. An electromagnetic
bomb delivered by a conventional aircraft can offer a much better ratio of electromagnetic device mass to total bomb mass, as
most of the bomb mass can be dedicated to the electromagnetic device installation itself. A missile borne electromagnetic
warhead installation will comprise the electromagnetic device, an electrical energy converter, and an onboard storage device such
as a battery. As the weapon is pumped, the battery is drained. The electromagnetic device will be detonated by the missile's
onboard fusing system.
LIMITATIONS OF E-BOMB
The limitations of electromagnetic weapons are determined by weapon implementation and means of delivery. Weapon
implementation will determine the electromagnetic field strength achievable at a given radius, and its spectral distribution. Means
of delivery will constrain the accuracy with which the weapon can be positioned in relation to the intended target. While the
relationship between electromagnetic field strength and distance from the weapon is one of an inverse square law in free space,
the decay in lethal effect with increasing distance within the atmosphere will be greater due quantum physical absorption effects.
THE IMPLICATION OF E-BOMB FOR INDIAN ARMED FORCE
Any Indian Land Forces unit equipped with an e-bomb might engage in a new way of war — with significant operational
advantages over nations equipped with conventional weapons only. Communications and command systems are key elements in
C4ISR systems for land warfare as well. Such systems are one of the first targets attacked in order to limit the opponent’s
operations. The Indian Armed Forces could use e-bombs to mount an effective attack against an enemy’s C4ISR systems.
Some of the possible threats for today’s naval forces have been defined as: Aircraft attack; Ship-based or land-based helicopters ;
Ship-launched or submarine-launched anti-ship missiles (ASM). The best defense against an opponent’s missile-equipped
platforms is to disable the delivering platform. In this aspect, the use of e-bombs may be a good defensive measure since it can
degrade the effectiveness of ASM delivering platforms such as aircraft and ship-based/landbased helicopters.