They have been seen in science fiction for
a hundred years and go by many names, heat
rays, death rays, lasers, masers, phasers,
disrupters and e-bombs, but they are all effectively
directed energy weapons and in theory they
could be the ideal weapon that works at near
the speed of light and with enough energy
could penetrate almost any material. But after
decades of research and many large scale failures,
the first directed energy weapons are being
deployed by the US military and others.
So is what is the future for these exotic
weapons and where might we see them and when?
This video is sponsored by Brilliant.
In a previous video we looked at the hypersonic
missiles which have the potential to be almost
unstoppable with current anti-ballistic missile
defence systems but I did add a little end
note saying that the only thing that could
potentially defeat them would be a directed
energy weapon.
The reason why is because shooting down a
missile be that a hypersonic one or a traditional
ballistic requires firing another equally
fast-moving projectile to intercept the target
either with direct hit it or exploding just
in front of it.
The task of getting your anti-ballistic missile
to be in the right place at the right time
is one of the most difficult engineering problems
tackled by any country.
But what if your interceptor or your bullets
could travel at almost the speed of light
and with a flat trajectory. Following even
a swerving hypersonic missile travelling at
somewhere between Mach 7 and Mach 20 would
become much easier.
Just look at the Chelyabinsk meteor, on video,
it looks quite slow but it hit the top of
the earth's atmosphere and burned up travelling
at around Mach 50, that’s over 61,000km/h,
faster than any missile, yet you could follow
its path with a handheld laser pointer from
the ground.
Now that the easy part, getting a laser powerful
enough to cause enough damage to destroy something
maybe 100km away in a few seconds is the hard
part.
Projectiles can do a lot of damage when they
hit because they have a lot of mass, sub-atomic
particles or light have virtually no mass
so you need a huge amount of them to have
any effect which in turn equates to a lot
of energy and it’s the supply of this energy
which is one of the biggest stumbling blocks
and the reason why you won't see handheld
energy weapons anytime soon unless there is
a revolution in energy storage and discharge.
One of the first practical attempts at approaching
this problem was Project Nike Zeus in the
1960s which used high-speed rockets to intercept
incoming ICMB’s and when they were within
a few hundred feet of the target explode a
nuclear warhead. The idea being that if it
wasn’t disabled by the blast, the EMP or
electromagnetic pulse would fry the control
electronics.
But there was a problem, during the high altitude
nuclear test, Hardtack Teak on the 1st August
1958, conducted in the Pacific, a 3.8 megaton
device was exploded at an altitude 250,000
ft or 76km. The fireball grew very large in
the near-vacuum at the top of the atmosphere
and the effect of the fissionable debris injected
into the ionosphere was so strong that it
disrupted high-frequency communications on
which the military depended over a wide area
of the pacific for up to 9 hours afterwards
The electronic noise created by the gamma
burst as it reacted with the air molecules
to produce huge amounts of positive ions and
recoil electrons also temporarily blinded
the radar systems in the direction of the
blast. A later nuclear test, Starfish prime
in 1962 detonated a 1.4 megaton device at
an altitude of 400km. That created an artificial
radiation belt around the earth that latest
for months and damaged not only electronics
1300km away in new Zealand but also destroyed
three satellites in orbit nearby.
Although these were not true directed energy
weapons, they proved that high energy electromagnetic
pulses could very damaging to enemy satellites,
communications, electronics and electrical
supply grids. The problem was that if the
were used as AMB system over home ground they
would have the same effect and blind the radars
tracking the ABM’s and looking for other
incoming ICBM’s as well damaging military
& civilian electronics in the US.
However, if the power of a nuclear blast could
be focused into a beam x-rays then it could
be used to shoot down ICBMs at great distances
in space where there would be no atmosphere
to absorb the X-rays and where they would
be most susceptible before the warheads had
separated.
This was one of the ideas for what would become
part of the Strategic Defense Initiative or
SDI, also known as Reagan’s Star Wars in
the 1980s.
Laser stands for “light amplification by
stimulated emission of radiation”, the first
laser was built in 1960 at the Hughes Research
Laboratories.
When normal light is generated from say a
light bulb, it spreads out in all directions
incoherently, the light waves are out of phase
and usually cover a board spectrum of frequencies
or colours.
In a laser, the light waves are Spatially
coherent or in phase with each other, so they
don’t cancel each other out and weaken the
output. This allows the light stay in a highly
focused beam over very long distances. They
can also be temporally coherent, meaning that
the light is just one frequency or one colour.
Because all the light is focused into one
small beam its energy is concentrated a bit
like when you focus the sun with a magnifying
glass.
Some of the first lasers consisted of a rod
of ruby with mirrored ends and flash tube
surrounding it. When the flash tube fires
the light starts a process called optical
pumping which raises the energy level of the
atoms in the ruby rod. This then cycles between
upper and lowers energy states and when this
happens it's said to be lasing.
Different light frequencies or colours carry
different amounts of energy, low frequencies
like radio, microwave and infrared are low
energy or non-ionising radiation whereas the
high-frequency Ultraviolet, X-ray and Gamma
rays are high energy ionising radiation. These
have enough energy to knock the electrons
off of atoms to create ions and damage living
cells which is why they are so dangerous to
us.
Project Excalibur was a cold war research
program run by the Lawrence Livermore National
Laboratory to make an X-Ray laser that would
be powered by a nuclear explosion and championed
by the Manhatten project theoretical physicist
Edward Teller and it became a major part of
the Strategic Defense Initiative.
To take the example of the simple ruby laser,
in an X-ray laser, the ruby rod is replaced
by one or more metal rods and a nuclear bomb
replaces the flash tube. If dozens of rods
surround the nuclear bomb, it was theorised
that each one could be aimed at a different
incoming ICBM, therefore when the device detonated
dozens of highly focused X-ray beams could
destroy many missiles at once.
Although testing had shown that lasing of
X-rays could be made to happen, the highly
optimistic view the project champion Edward
Teller was completely out of step with what
the technology was capable of at the time,
not only in the weapon design but in things
like the supercomputing power required to
track all the targets and aim the beams on
to them in realtime.
As time went by it became clear that this
was still well beyond the technology of the
time and other issues with things like the
metal lasing rods cast doubt on whether it
could work at all and by 1992 Project Excalibur
was cancelled.
This brings us on to the optical laser systems
which we do know work. These have been in
development since the 1960’s and range from
things like lasers mounted on ships to defend
against small high speed boats, to the Boeing
YAL-1A airborne laser testbed. This used a
laser which was mounted on the front of a
Boeing 747 and was designed to use a megawatt
class chemical oxygen-iodine laser to shoot
down tactical ballistic missiles which are
slower and lower altitude than ICMB’s.
But the problem with high powers lasers is
the atmosphere itself. Over longer distances
which would be needed to affect high-speed
targets, turbulence in the air can refract
the beam, weakening it. As the power goes
beyond about 1 megajoule per cubic centimetre,
the laser starts to create a plasma in the
air which diffuses and scatters the beam,
this is called blooming and it becomes worse
if there are particles in the air such as
fog, smoke, dust, rain, smog or chemicals
deliberately dispersed by an enemy.
To try and minimise blooming, various techniques
can be used including multiple beams, pulsed
lasers, laser beam shaping, phase correction
and adaptive optics but the only place where
a laser can be exploited to its fullest extent
is where there is no atmosphere to get in
the way and that is space.
The Boeing Airbourne laser was cancelled because
it would need to have been flying over the
enemy territory for long periods waiting for
missiles to be launched to be close enough
for the laser to be effective. To cover a
wide area, a fleet of these would be required
to be in the air 24/7, all being targets for
enemy missiles and fighters. And it wasn’t
as if the laser burned a hole in the missile,
all it would do is to heat up a portion of
the outer skin which would then weaken it
and cause the structure of the missile to
fail with the stress of flying through the
air. So a defence against such a laser could
be as simple as a coating that reflects laser
light and greatly reducing the heating effect.
This idea hasn’t been entirely dropped as
it been suggested that a fleet of UAV’s
could be fitted with lasers and fly at very
high altitudes to achieve a similar purpose.
These could be refuelled in mid-air to give
them extremely long flight durations allowing
them to loiter around until missiles are launched.
Other uses for lasers are handheld guns to
dazzle or temporarily blind troops and more
high power ones to blind the infrared heat
sensors on surface to air and air to air missiles,
this is one of the features of the F-35 as
part of its electronic warfare system.
Other methods which have been tested include
particle beam weapons which shoot a beam of
high energy particles, either as ions or neutral
particle beams. This method is commonplace
particle accelerators like synchrotrons and
cyclotrons and used in places like the Large
Hadron collider at CERN.
Advanced accelerators can accelerate large
heavy subatomic nuclei like iron or mercury
to near light speed, these carry a lot of
kinetic energy which is converted into heat
when they hit the target material causing
rapid superheating at the surface and ionising
effects at deeper levels which could damage
electronic devices in a missile for example.
In 1989 as part of the Strategic Defense Initiative,
a low power neutral particle beam accelerator
was successfully tested in orbit before being
returned intact and is now is at the National
Air and Space Museum. But to date no weapon
using this technology has been deployed, partly
because the power supply required and size
of the magnets to make a viable weapon would
be too large to make it portable.
But what have become deployable systems are
ones based on high power microwaves. These
have had a controversial history with systems
like the Active Denial System developed by
the US military which are designed to control
crowds or provide perimeter security and where
used in Afghanistan in 2010 to control crowds
without using live fire.
These work on the same principle as a microwave
oven by exciting water molecules in the skin
causing them to heat up and create a burning
sensation, basically to get people to move
away from the area without using lethal force
or causing permanent injury. As some have
stated it fills in the gap between shouting
and shooting.
The difference between this and a microwave
oven is the frequency of the ADS is much higher
at 95Ghz to the 2.45Ghz of a microwave oven.
This means that it can only penetrate the
top layer of skin to about 0.4mm compared
to the 17mm of the lower frequency oven. The
Current system ADS II, uses 100kw output to
cover a wide area but can be focused on smaller
areas farther away.
However, just as anyone with a microwave oven
will know, if you wrap your food or yourself
in a conductive material like aluminium foil
or specialist electromagnetically shielded
clothing, you create a faraday shield which
greatly reduces the effectiveness of such
a device.
But that hasn’t stopped the development
of what some people call E-bombs, high power
microwave systems used to destroy computers
and other electronic devices. Just as was
found in the nuclear tests, you can induce
large electrical currents into any unshielded
electrical system if you expose it to high
power radio waves. Again, if you put a fork
or spoon in a microwave oven you will see
the sparks jumping as the metal acts as an
aerial but you don’t need a continuous beam
of microwaves to damage modern microelectronics.
A very short pulse of microwaves, as short
as 100 nanoseconds but a very high peak power
up to 1GW can instantly fry the tiny transistors
in modern IC’s.
The US airforce as an already deployed cruise
missiles with such a system called CHAMP or
Counter-Electronics High Power Microwave Advanced
Missile Project. The idea is that these would
be dropped from a B-52 and fly to the target
area and then zap individual buildings with
a focused beam of microwaves, destroying computers
and electronic systems inside.
This would allow them to target buildings
which are deemed a military threat such as
regional headquarters but leave civilian ones
like hospitals untouched. Because the high
energy pulse of microwaves is very short it
doesn’t have time to heat up water molecules
in living tissue and cause burns and as such
is no threat to the people inside the building.
Similar High Power Microwave weapons are also
expected to be integrated into the F-35 and
other UAVs by the mid-2020s.
Another area where this type of targeted microwave
weapon is being used is against drones and
drone swarms like those that attacked the
Saudi oil refineries and are being used by
other countries too.
With easily available commercial drones able
to carry out spying operations or even carry
small but deadly high explosives, using high
power microwave pulses to destroy their electronics
would stop them dead in their tracks and they
would fall out of the sky. Even if the electronics
are shielded, the GPS ariel which is the drones
rely upon for guidance is still exposed. Even
our old friend the lasers are being used to
burn the frame of the drones causing structural
failure.
Raytheon has built and tested two systems
for the US army one using high power microwaves
and the other using high power lasers as counter-drone
weapons.
For a glimpse of the future, there are rumours
of similar systems being under development
using microwave or lasers combined with high-speed
tracking radar that is optimised for shooting
down artillery shells, mortar and rockets
in flight by heating their explosive charge
until they detonate.
As our technological world is now so dependent
on electronic equipment, the threat from the
emerging energy weapons is a very real one.
An e-bomb could potentially knock out an entire
city and whilst it doesn’t damage buildings
and people directly, the effects would set
you back to the steam age until repairs and
replacements could be effected. But if you
know-how electromagnetic waves work then you
could build your own faraday protection just
like we saw in the video.
Now our sponsors Brilliant, might not tell
you how you make your own EM protection but
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electromagnetic radiation and much more.
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