Hi, I understand that Laser weapons being tested by US military involves using a high powered beam of Infrared beam to heat up a target.
But why Infrared?
Now, I have no experience in this stuff, but if I recall, Microwave heats a target, especially metallic target, far more efficiently than Infrared.
Since most of the military hardware is covered in metal, a microwave beam would heat it up with ease due to induced osculating current.
A good comparison would be a Microwave Oven and an Infrared Oven of the same wattage, the Microwave oven could heat up food many times faster, WITHOUT heating up the air, or dishes holding the food directly.
So, a beam of microwave would allow a far longer distance without much drop in power.
Plus, as an added bonus, a beam of Microwave energy would fry any electronics that get in the way.
I guess I am suggesting, why not use some kind of Microwave Laser, be it a MASER or a really good and powerful radar that can focus in a very very narrow beam?
Microwave heats up food by exciting the water molecules in the food. As far as I know, microwave doesn't heat up metal. The spark you see from metal in a microwave oven is from the metal reflecting the microwave back to the magnatron that generated the radiation.
Infrared is heat, or what we feel as heat. It heats up all sorts of stuff very well.
"Only Nixon can go to China." -- Old Vulcan proverb.
Why would metal objects, i.e. spoons, forks, plates, etc get REALLY hot in microwaves, in a very short amount of time?Originally Posted by gunnut
I know infrared is heat, but problem with infrared is that you tend to be heating all the air that get in the way. Not very efficient.
Depends on the type of metal, not all reflect MWVE energy the same. Usually, they just absorb the ambient heat from the substance being heated.
I think we need to focus on lightsabers and blasters anyway!
What about sharks with "lasers" on their foreheads?
The best part of repentance is the sin
The big problem with directed radiation weapons is the physics, the inverse square law shows us that the delivered energy diminishes as the inverse square of the distance from the emitter. There are additional problems, like attenuation when passing through a media like air. The power required to deliver a decisive energy fluence at a distance is massive. Perhaps an explosive capacitive discharge could provide cartridge weapons with enough power. With today's technology they would probably be pretty large, like a crew served weapon using conventional ammunition, and probably delivering destructive energy at line of sight combat ranges on the order of a 0.50 cal M2 Browning - but without the need for leading the target or compensating for elevation and projectile drop. Tests so far have required the big stationary emitters to dwell on the targets for a significant period to damage it. So the bottom line is the modern projectile weapons we have now are more deadly and lighter.
"If your plan is for one year, plant rice. If your plan is for ten years, plant trees.
If your plan is for one hundred years, educate children." -- Confucius
If I remember correctly when a laser beam hits a material, then 3 basic things happen.
1 A part of the laser energy is refracted. (refraction)
2 A part of the laser energy passes/shines trough the material. (absorption)
3 A part of the laser energy is absorbed and converted to heat. (transmission)
The amounts of 1, 2 and 3 depend on the material properties (complex refractive index) and the wavelength of the laser. Due to this a CO2 laser will cut glass, which makes it unsuitable for use with a glass fiber *1), while a NDYAG laser will pass through glass and can use a glass fiber to direct the laser beam.
*1) If I recall correctly there are fibers that can guide CO2 laser beams of other materials.
Then there is the effect of laser polarisation on the amaount of these 3 factors.
There is also the effect of plasma formed by the material that is vaporised by the laser.
- Where that plasma absorbs almost all of the laser energy which turns into
heat, which is then transferred by the plasma to the material, provided the plasma
stays in contact with the material.
- Where so much laser energy is put into that plasma that the plasma cloud loses
contact with the material and shields the material below.
(why I would consider research into plasma stealth, not for stealth reasons, but as a
shield for laser weapons)
And then there also is the effect the atmosphere has on the laser beam, which can also absorb laser energy, scatter light and the effects of water vapor, etc, etc...
Im also not experienced with this stuff, but I've been hearing good things about the Tactical High-Energy Laser (THEL) and the Mobile version(MTHEL).
This is also know as the Nautilus Laser System.
But there are countermeasures to this of course, so far these are only in theory.
1. Reflective coatings which attempt to reflect a large proportion of the incident radiation which is incident upon the aimed projectiles.
2. Modification of projectile geometries to take into account the possibility that laser light radiation might be used to neutralize the projectiles.
3. Enveloping gas/substance the use gaseous envelopes around a missile would ensure that a sufficiently cool gas will carry away a portion of the incident radiation energy which is incident upon the missile by both convective and diffusive effects.
4. An oscillating or chaotic trajectory will increase the difficulties in the use of the THEL system due to guidance. If guided into windy or turbulent environments, such a chaotic trajectory would also ensure that there is more of a turbulent gaseous flow around the missile.
5. Heat Resistant Coating Layers (HRCLs). Similar to reflective coatings. However, in the case of HRCLs, internal capillaries/coolant mechanisms could ensure that excessively large amounts of heat could be dissipated.
6. Multi-stage projectile systems which “dummies” a THEL kill.
Last edited by Durian10; 07 Dec 10, at 19:45.
all three were prototypes not actual weapons.
YupBut there are countermeasures to this of course, so far these are only in theory.
Albedo ratign is the key here. The closer you get to 1 the more energy you reflect. However, nothing is perfect and even highly polished silver would rapidly tarnish in storage or sear during re-entry thus lowering albedo much closer to 0.1. Reflective coatings which attempt to reflect a large proportion of the incident radiation which is incident upon the aimed projectiles.
doutbful, you can't reflect light like you can radio waves (through shaping alone)2. Modification of projectile geometries to take into account the possibility that laser light radiation might be used to neutralize the projectiles.
Impossible for ballistic targets, re-entry heat actually makes the lasers job easier.3. Enveloping gas/substance the use gaseous envelopes around a missile would ensure that a sufficiently cool gas will carry away a portion of the incident radiation energy which is incident upon the missile by both convective and diffusive effects.
simple software issue4. An oscillating or chaotic trajectory will increase the difficulties in the use of the THEL system due to guidance. If guided into windy or turbulent environments, such a chaotic trajectory would also ensure that there is more of a turbulent gaseous flow around the missile.
You talking encasing weapons in thermal superconductors....5. Heat Resistant Coating Layers (HRCLs). Similar to reflective coatings. However, in the case of HRCLs, internal capillaries/coolant mechanisms could ensure that excessively large amounts of heat could be dissipated.
That only drives the need for more powerful lasers so they can cycle through the dummies faster, and better sensor fusion for target discernment.6. Multi-stage projectile systems which “dummies”
low slow stealthed cruise missilesa THEL kill.
My limited understanding is that both technologies are being developed as weapons. I beleive air is more transparant to certain frequencies of infrared light than visible light (corrections please???) which means the beam can travel useful distances and then deliver energy to a target - hence the focus on those frequencies - you get longer longer range for your buck. Focused microwaves on the other hand can be used to disrupt sensitive electonics in certain vehicles and buildings as well as "pain" or area denial weapons for crowd control (causing pain on unprotected skin).
At this stage neither type of weapon is practicle as a "heavy hitter" due to the dreaded inverse square law which makes the power requirements for an effective weapon so large. I believe Boeing has being trying to develope an air born laser weapon that will fit inside a converted 747 for use in destroying missiles during their launch phase but so far, despite years of effort the results have been "disapointing" at best. So long story short no "phasers" for anyone in the forseeable future. ....Cheers
Last edited by Monash; 11 Dec 10, at 04:26.
Well like i said.... these countermeasures are only in theory. But thanks for telling me this. :D
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