Game Development Reference
In-Depth Information
HELEX
The goal of the High Energy Laser Experimental (HELEX) program being studied in Germany is
to develop a multimegawatt laser-based missile and antiaircraft defense system.
5
The HELEX
system uses a CO
2
laser that is mounted on top of a tracked armored vehicle such as a Leopard 2
tank. The HELEX laser beam is directed to its target by way of a system of mirrors and an adjust-
able scaffolding. The vehicle is designed to carry enough fuel to fire 40-50 laser shots.
Some of the technical specifications for the HELEX air defense system are shown in
Table 14-5. The HELEX system has a much shorter effective range than either the ABL or SBL
systems, and is the least exotic of the three systems presented in this section. The CO
2
for the
laser is created by burning two common compounds—benzene and nitrous oxide.
Table 14-5.
HELEX Specifications
Quantity
Value
Laser type
CO
2
chemical gas
Wavelength
9350 or 10,600 nanometers (infrared)
Average power
2-3
MW
Range
5-10
km
System mass
18,000-36,000
kg
(including vehicle mass)
Laser Damage
Now that we have talked at some length about the theory of lasers and discussed details of
some current or proposed laser systems, it's time to talk about ways to estimate the damage
caused by military lasers. Military lasers are used primarily to burn through things and to
disable electronic devices. In both instances, the damage inflicted on the target is a function of
the amount of laser energy that is absorbed by the target. The absorbed energy is equal to some
fraction of the power density of the beam,
I
, multiplied by the duration of the contact of the
beam with the target,
t
.
EIt
=
α
(14.4)
term is an absorption factor to account for the fact that the target
won't absorb all of the energy in the laser beam. The nominal beam energy will be decreased
due to transmission losses in the optical system and the atmosphere. Part of the laser energy
that strikes the target will be reflected off of the target surface. The amount of reflection is a
function of the target material, the surface finish of the target, and the wavelength of the laser beam.
Highly reflective materials, as you might expect, reduce the absorption factor. The absorption
factor for a ruby laser beam with a wavelength of 694 nanometers is 0.11 for aluminum, 0.35 for
light-colored human skin, and 0.2 for white paint. Higher-wavelength laser beams tend to have
higher absorption factors. The absorption factor for a CO
2
laser beam with a wavelength of
10,600 nanometers is 0.95 for light-colored human skin.
In Equation (14.4), the
α
