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Electromagnetic vs Kinetic Energy

  1. Sep 12, 2011 #1
    Looking at this in a weapon point of view, what would be the more effective one?

    Say we have a 155mm projectile travelling and hitting a hard target(metallic), lightly and heavily armored, at different times, both with an impact energy of 530 MJ.

    Also say we have a very short IR laser pulse with a beam diameter of 155mm also hitting lightly and heavy armored targets, with an energy of 530 MJ.

    What would be the effects of each in a vacuum? Would it change very much to do it in atmosphere (besides the associated drop in velocity with more range for the projectile)?
    The projectile most definitely seems it would be much more devastating but I just wanted to get some realistic answers on this.
  2. jcsd
  3. Sep 12, 2011 #2
    What a laser!!!! 530 MJ!!!
    Let's put aside the huge amount of energy and analyze pros and cons of conventional and laser weapons.
    An IR laser can be easily defeated by applying a silver coating. Certainly, a lot of the coating would be vaporized but the target would be largely unharmed.
    If we had a X-ray laser things would be different since X-rays can´t be stopped that easily. Thirty years ago, Edward Teller "sold" this idea to president Reagan who funded the project heavily. The result was a complete fiasco. Go and buy a good powder-powered cannon. It´s heavy, beautiful and it makes a lot of noise.
  4. Sep 13, 2011 #3
    I agree, what is already being used definitely fills the need and is optimal. Railguns/coilguns seem like a better choice for future weaponry imo than lasers.

    But okay, lets throw out the energy values, if a laser and bullet of equal size/energy hit and went through the roof of a ww2 half track from above with intention of knocking out the driver, would the effects of each be very much different?

    Also, how would a laser of fairly high irradiance act on a fleshy target?
  5. Sep 13, 2011 #4
    easy rider:

    I know little about laser weapons except that they ARE being developed; So I have my doubts that the posts so far are objective. "effective" might not be the same as "devastating", but it SEEMs as if the projectile would do the most damage once it hit. An apparent advantage of new projectiles is that they are "SMART"...self guided or remotely so.

    you might find this brief discussion of interest:

  6. Sep 13, 2011 #5
    I know that we, as in USMIL (Im in the Army), are developing all kinds DEWs. I dont know what you mean by "not objective"? IMO lasers definitely have their place, especially in anti-aircraft, anti-satellite, and all around long range weapons used against high speed moving targets. Absolutely nothing can match the speed and accuracy of a laser so they lend themselves to being great weapons for moving targets. My favorite thing in science fiction is the death star, lol (I think the weapons in Star Wars were a little bit more plausible than Star Trek-ie "quantum torpedoes" for one, though they were both far fetched). Ignoring that it takes more energy to do what the death star did than the amount the sun produces per second, the stats are crazy, 2.4E32 Watts and low enough divergence for a range of 6 light seconds. But thats the reason its fiction, so yeah.
    The reason I was asking this was because I heard the Navy cut funding for their railgun. Of course the economy is in bad shape but shouldnt they cut down on things that are totally useless to the country, such as the presidents campaign and his and the first lady`s staff? I think they also did the same to the FEL which is a shame as the potential for it is high. Im not saying they should pick one over the other, but along with all the R&D going to lasers, I think they should try doing more stuff with electric gun tech such as railguns/coilguns as the muzzle velocity can be huggee.
  7. Sep 26, 2011 #6


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    I think this highly depends on the duration of the laser pulse. If it takes several seconds to deliver this energy, the most likely effects (I'm guessing) would that the laser simply burns through. If all that energy were delivered in about 1 millisecond I think there would be something a akin to an explosion.
  8. Sep 27, 2011 #7


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