Laser weapons general thoughts
- Thread starter Lexx
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Straybow
SOC-14 1K
We can't do gamma and x ray astronomy from the ground because the air absorbs and scatters so much of the energy that it can't be detected as point source radiation.
In the case of NWE the frequences generated by superheated matter are more limited and happen to lie in a region of high absorbtion by air molecules. The majority of gamma radiation gets absorbed to form the fireball but dangerous levels still penetrate much farther.
In any case, a laser is a different matter entirely. Any laser heats the air as it passes through (that's what absorption means). The photon flux of a laser is many orders of magnitude higher than the tiny volume of air can absorb. A partial vaccuum is formed through which the majority of the laser passes undiminished.
The defense laser data indicated is for bomb-pumped graser warheads. The beams generated are not as narrow as other methods of generating laser beams, therefore they are not as effective at penetrating atmosphere. Below 8 mi (12 km) water vapor and dust also occlude the graser.
I guarantee you would not enjoy being hit by an orbital graser. The energy density would not be sufficient to guarantee a high percentage kill on a missile but flesh is more sensitive. Remember that the 20/21 century bomb-pumped orbital grasers are single-use weapons that must be boosted into orbit at enormous cost.
Man-portable weapons in those frequencies would have ranges limited by intervening terrain rather than intervening air, just like any other laser. What worries me is the energy level required to cause gamma/x lasing in a weapon held in my hands could be more dangerous than the enemy.
In the case of NWE the frequences generated by superheated matter are more limited and happen to lie in a region of high absorbtion by air molecules. The majority of gamma radiation gets absorbed to form the fireball but dangerous levels still penetrate much farther.
In any case, a laser is a different matter entirely. Any laser heats the air as it passes through (that's what absorption means). The photon flux of a laser is many orders of magnitude higher than the tiny volume of air can absorb. A partial vaccuum is formed through which the majority of the laser passes undiminished.
The defense laser data indicated is for bomb-pumped graser warheads. The beams generated are not as narrow as other methods of generating laser beams, therefore they are not as effective at penetrating atmosphere. Below 8 mi (12 km) water vapor and dust also occlude the graser.
I guarantee you would not enjoy being hit by an orbital graser. The energy density would not be sufficient to guarantee a high percentage kill on a missile but flesh is more sensitive. Remember that the 20/21 century bomb-pumped orbital grasers are single-use weapons that must be boosted into orbit at enormous cost.
Man-portable weapons in those frequencies would have ranges limited by intervening terrain rather than intervening air, just like any other laser. What worries me is the energy level required to cause gamma/x lasing in a weapon held in my hands could be more dangerous than the enemy.
Straybow
SOC-14 1K
We can't do gamma and x ray astronomy from the ground because the air absorbs and scatters so much of the energy that it can't be detected as point source radiation.
In the case of NWE the frequences generated by superheated matter are more limited and happen to lie in a region of high absorbtion by air molecules. The majority of gamma radiation gets absorbed to form the fireball but dangerous levels still penetrate much farther.
In any case, a laser is a different matter entirely. Any laser heats the air as it passes through (that's what absorption means). The photon flux of a laser is many orders of magnitude higher than the tiny volume of air can absorb. A partial vaccuum is formed through which the majority of the laser passes undiminished.
The defense laser data indicated is for bomb-pumped graser warheads. The beams generated are not as narrow as other methods of generating laser beams, therefore they are not as effective at penetrating atmosphere. Below 8 mi (12 km) water vapor and dust also occlude the graser.
I guarantee you would not enjoy being hit by an orbital graser. The energy density would not be sufficient to guarantee a high percentage kill on a missile but flesh is more sensitive. Remember that the 20/21 century bomb-pumped orbital grasers are single-use weapons that must be boosted into orbit at enormous cost.
Man-portable weapons in those frequencies would have ranges limited by intervening terrain rather than intervening air, just like any other laser. What worries me is the energy level required to cause gamma/x lasing in a weapon held in my hands could be more dangerous than the enemy.
In the case of NWE the frequences generated by superheated matter are more limited and happen to lie in a region of high absorbtion by air molecules. The majority of gamma radiation gets absorbed to form the fireball but dangerous levels still penetrate much farther.
In any case, a laser is a different matter entirely. Any laser heats the air as it passes through (that's what absorption means). The photon flux of a laser is many orders of magnitude higher than the tiny volume of air can absorb. A partial vaccuum is formed through which the majority of the laser passes undiminished.
The defense laser data indicated is for bomb-pumped graser warheads. The beams generated are not as narrow as other methods of generating laser beams, therefore they are not as effective at penetrating atmosphere. Below 8 mi (12 km) water vapor and dust also occlude the graser.
I guarantee you would not enjoy being hit by an orbital graser. The energy density would not be sufficient to guarantee a high percentage kill on a missile but flesh is more sensitive. Remember that the 20/21 century bomb-pumped orbital grasers are single-use weapons that must be boosted into orbit at enormous cost.
Man-portable weapons in those frequencies would have ranges limited by intervening terrain rather than intervening air, just like any other laser. What worries me is the energy level required to cause gamma/x lasing in a weapon held in my hands could be more dangerous than the enemy.
When the air absorbs the shortwave radiation it is converted into heat. That means the air superheats and blooms, leving a vaccuum for the rest of the pulse to pass through. Kinda like Lexx's idea except the short wave laser burns it's own hole in the air, creating a breif brilliant, white line to the target like an arrow-straight lightening bolt.
Isn't that what fictional lasers are supposed to do?
Attenuation will take hundreds of meters even at sea level pressure. That limits its use as an orbital weapon, but it can be useful tactically.
Isn't that what fictional lasers are supposed to do?
Attenuation will take hundreds of meters even at sea level pressure. That limits its use as an orbital weapon, but it can be useful tactically.
When the air absorbs the shortwave radiation it is converted into heat. That means the air superheats and blooms, leving a vaccuum for the rest of the pulse to pass through. Kinda like Lexx's idea except the short wave laser burns it's own hole in the air, creating a breif brilliant, white line to the target like an arrow-straight lightening bolt.
Isn't that what fictional lasers are supposed to do?
Attenuation will take hundreds of meters even at sea level pressure. That limits its use as an orbital weapon, but it can be useful tactically.
Isn't that what fictional lasers are supposed to do?
Attenuation will take hundreds of meters even at sea level pressure. That limits its use as an orbital weapon, but it can be useful tactically.
kilemall
SOC-14 5K
Hmm, looked into all this as a result of my EM sensor study, wondering what a graser would be like.
Obviously we got X-ray lasers early on in Traveller gamelore with the Striker and HG laser increases, I would expect grasers to be a TL14-15 thing in CT.
Or maybe that's what a PA barbette is- which illustrates another point, grasers would be a radioactive hell weapon in addition to it's greater damage potential.
Are grasers just a form of PA weapon?
And on the personal or vehicle-based front, are they messier to use then plasma/fusion guns due to their PA-like effects in atmo?
I'm thinking they would play much like MgT's version of FGMPs being a rad-weapon, and thus maybe a badguy/total war weapon in the same category as nuke us- only the nuclear dampers can't stop the graser.
Obviously we got X-ray lasers early on in Traveller gamelore with the Striker and HG laser increases, I would expect grasers to be a TL14-15 thing in CT.
Or maybe that's what a PA barbette is- which illustrates another point, grasers would be a radioactive hell weapon in addition to it's greater damage potential.
Are grasers just a form of PA weapon?
And on the personal or vehicle-based front, are they messier to use then plasma/fusion guns due to their PA-like effects in atmo?
I'm thinking they would play much like MgT's version of FGMPs being a rad-weapon, and thus maybe a badguy/total war weapon in the same category as nuke us- only the nuclear dampers can't stop the graser.
It's not a few feet of air, but above a certain energy the x rays will sink energy into ionising the air, which will absorb energy fairly quickly. The phenomenon is called bleaching. Bleaching will absorb energy until all of the electrons have been stripped off the atoms. While the effect is not infinite, it does have a lot of scope to absorb energy.
The other limiting factor of x ray lasers (at least those made from rods pumped by a nuclear explosion) is the collimation. The collimation of the beam produced is proportional to the ratio of the width of the rods to their length. If you try to make the rods too thin then you get diffraction effects that spread the beam. This makes for a practical limit on the collimation that is possible with this type of laser.
mike wightman
SOC-14 10K
It's not the gamma ray absorption of air I was criticizing, it was the idea that a few feet of air would render a gamma ray laser useless.
I have a radiation source at work that emits gamma - those gamma rays can be detected using a GM tube through tens of metres of air no problem at all. In fact they can be detected through two concrete walls and tens of metres of air.
I have a radiation source at work that emits gamma - those gamma rays can be detected using a GM tube through tens of metres of air no problem at all. In fact they can be detected through two concrete walls and tens of metres of air.
Enoki
SOC-14 1K
Well, attenuation of gamma rays is well known. So depending on the intensity of the gamma rays when emitted one, and their quantity it should be easy to determine the energy that would strike a target at any distance from it. That might even be converted into a dosage so even if the target weren't seriously injured or killed the weapon might cause sufficient radiation damage that several days later the target dies.
So, it depends on the energeticness of the gamma rays emitted. At .5 MeV the attenuation is 50% per 60 meters roughly. At .1 MeV it would be about 35 meters .5 MeV is equal to about 2.25 watts. So, if your laser was emitting .5 MeV gamma at say 20 KW, you'd have 10 KW at 60 meters, 5 KW at 120 meters, etc.
In terms of a "laser"- like weapon this would be focused on a very small area over a very short period of time (micro to milli seconds) so the effect would be pretty bad and you'd also have to take into account how much the beam diffused as it travelled. I don't know if there's any way to calculate that off hand however.
So, in the above example, if you had the burst last say one millisecond (roughly the striking time of a bullet), at 120 meters this weapon would impart on the target (assuming the same cross section of striking area as a 30.06 bullet) about 5,000 joules versus 542 for the bullet. I'd say it would definitely do some serious damage. This would give the 20 KW gamma laser with a .5 MeV energy level an effective range of about 300 meters (625 joules).
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Straybow
SOC-14 1K
Gamma and X rays are synonymous, except that by convention Xs are produced by electron activity, while gammas are nuclear radiation, including particle-antiparticle annihilation rays.
Since lasers are electron energy derived, grasers should technically be called x-rasers, but graser has become a more convenient term for pronunciation and writing.
50% attenuation over 60m is for nonlaser sources. Bomb-pumped orbital grasers are very low quality beams but they will attenuate over km, not 10s of meters. The percentage of energy that gets absorbed by each km of atmospheric gas and suspended particles is rather low, but the military application needs one-shot-one-kill results to justify the $100k/lb launch expenses.
Since lasers are electron energy derived, grasers should technically be called x-rasers, but graser has become a more convenient term for pronunciation and writing.
50% attenuation over 60m is for nonlaser sources. Bomb-pumped orbital grasers are very low quality beams but they will attenuate over km, not 10s of meters. The percentage of energy that gets absorbed by each km of atmospheric gas and suspended particles is rather low, but the military application needs one-shot-one-kill results to justify the $100k/lb launch expenses.
http://panoptesv.com/SciFi/LaserDeathRay/DamageFromLaser.php
This is a calculator for damage from a laser hit. You can plug in the numbers and get an effect on various materials. Enjoy.
kilemall
SOC-14 5K
Isn't that assuming a photonic laser? Wouldn't a graser have different properties beyond 'just' an increase in power/joule output?
Enoki
SOC-14 1K
Yes, for one, the gamma that strays from the main beam itself would still be dangerous as radiation. The energy of the gamma radiation itself would also make it more, or less, effective against certain materials. That is different materials absorb or are penetrated by varying energy levels of gamma radiation at different rates.
You could also make the striking time longer meaning that for a given amount of energy continuously poured into the target you get a desired result. Thus, as firing distance to the target increases the striking time is also increased, keeping the amount of damage done relatively constant.
Doing that makes the limits on the weapon's range line-of-sight (more or less) and the time available to strike the target continuously.
kilemall
SOC-14 5K
Hmm, on the continuous fire/damage issue, I am assuming for both personal and ship combat that one will not have more then one second.
A person getting hit by a laser will be instinctively moving/convulsing/going down, and ships IMO are at the least using thrusters to constantly roll or change yaw, and with agility added on main engines, accelerating in likely unexpected directions.
I would expect weapons to be able to achieve multiple hits, but just not be able to keep the hit on one specific point.
A person getting hit by a laser will be instinctively moving/convulsing/going down, and ships IMO are at the least using thrusters to constantly roll or change yaw, and with agility added on main engines, accelerating in likely unexpected directions.
I would expect weapons to be able to achieve multiple hits, but just not be able to keep the hit on one specific point.
Enoki
SOC-14 1K
As I demonstrated in my previous example, a 20KW burst of .5MeV gamma for a millisecond at 120 meters has roughly ten times the striking power of a 30.06 bullet applied to the same diameter of area.
So, I'd think that a 10 millisecond burst would be pretty devastating out to several hundred meters. An eye blink is about 300 to 400 milliseconds...
I'd think getting hit by a laser would be much like getting hit by a bullet only without the kinetic energy of impact. Now, if the laser were operated to sweep across the target, it'd be like getting hit with an invisible sword that chops a chunk of you off.
This would be a pulsed weapon in my view, rather than a beam weapon. The big question would be What is the rate of fire? That is, how long between pulses lasting how long, or how long you can keep the beam going. If you could keep the beam going at full strength for even a tenth of a second, you could cut down a pretty wide swath of targets sweeping it across them.
Straybow
SOC-14 1K
Most lasers are pulsed in the millisecond range. When target material begins to vaporize it becomes reflective, especially metals. The gasses can absorb quite a bit of energy and reflect another chunk of energy. So, military lasers shoot a stream of short pulses that allow the vaporizing material to disperse.
ABL was a little different, mainly because the beam was about a foot in diameter. It would superheat (but not completely melt) a larger patch of target material which would cause catastrophic structural failure. An airplane engine hit by it would structurally explode as the materials heated past their limits.
ABL was a little different, mainly because the beam was about a foot in diameter. It would superheat (but not completely melt) a larger patch of target material which would cause catastrophic structural failure. An airplane engine hit by it would structurally explode as the materials heated past their limits.
