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Post by newageofpower on Jan 15, 2017 7:24:01 GMT
I was arguing that the game has an inaccurate representation of laser damage. I assumed the same as well, but didn't want to continue the argument until verification.
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Post by caiaphas on Jan 15, 2017 7:31:31 GMT
That was not at all evident to me in your original post, but I can see what you're saying somewhat in later posts. My apologies. EDIT: Right, so since I can't see the image at all, I'm running off of calcs that other people did later in the thread. So the laser hits in a circle 20 um across, so let's assume that it digs a hemispherical divot with that radius and that all of the diamond in that hemisphere flashes into plasma of T = 75000 K. Some basic PV = nRT calcs using the molar mass of carbon and the density of diamond gives a pressure of 624 kPa, or six orders of magnitude smaller than diamond's yield strength of 1.6 GPa. There's going to be an explosion, yes, but not one that actually deforms the armor to any extent, and the issue is compounded by the fact that there's not really going to be any containment of that plasma, so the pressure might not even build up to that point, it'll tend to just escape into space. Also, how the hell did you get that plasma temp, RiftandRend?
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Post by leerooooooy on Jan 15, 2017 15:00:15 GMT
Wait till you notice that transparency is only partly accounted for: transparent materials only take damage from a fraction of the energy entering them (which is correct) but zero energy reaches the layer under them (obscenely wrong).
Lasers are broken even worse than coilguns IMO
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Post by RiftandRend on Jan 15, 2017 15:16:12 GMT
That was not at all evident to me in your original post, but I can see what you're saying somewhat in later posts. My apologies. EDIT: Right, so since I can't see the image at all, I'm running off of calcs that other people did later in the thread. So the laser hits in a circle 20 um across, so let's assume that it digs a hemispherical divot with that radius and that all of the diamond in that hemisphere flashes into plasma of T = 75000 K. Some basic PV = nRT calcs using the molar mass of carbon and the density of diamond gives a pressure of 624 kPa, or six orders of magnitude smaller than diamond's yield strength of 1.6 GPa. There's going to be an explosion, yes, but not one that actually deforms the armor to any extent, and the issue is compounded by the fact that there's not really going to be any containment of that plasma, so the pressure might not even build up to that point, it'll tend to just escape into space. Also, how the hell did you get that plasma temp, RiftandRend ? I thought "In order to beat the dead horse even more, I built the strongest laser I could and tested it at the shortest ranges I could." Implied that. I got that temperature through an incredibly simplistic (and inaccurate) calculation. I applied 375 Mj to 9 kg of diamond, roughly what occupies a .020 mm x 300 mm target. I applied it uniformly and instantly, which would not happen. To see the image you're going to have right click on the and open it in a new tab. If there's a better way to display it please tell me.
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Post by svm420 on Jan 15, 2017 15:55:54 GMT
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Post by Rocket Witch on Jan 15, 2017 17:39:43 GMT
Wait till you notice that transparency is only partly accounted for: transparent materials only take damage from a fraction of the energy entering them (which is correct) but zero energy reaches the layer under them (obscenely wrong). Lasers are broken even worse than coilguns IMO I hope we get visual transparency before or at that point or it's going to be a bit confusing.
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Post by morrigi on Jan 15, 2017 18:28:43 GMT
That much energy in one place should probably cause detonation of the target area, which is incidentally why pulse lasers (which we don't have for some reason) are superior to continuous-beam lasers for many applications
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Post by newageofpower on Jan 15, 2017 19:02:14 GMT
That much energy in one place should probably cause detonation of the target area, which is incidentally why pulse lasers (which we don't have for some reason) are superior to continuous-beam lasers for many applications Stress on a pulsed laser is far higher than a continous beam. But yes, those would benice, as well as FEL setups.
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Post by michalo on Jan 15, 2017 19:56:35 GMT
That was not at all evident to me in your original post, but I can see what you're saying somewhat in later posts. My apologies. EDIT: Right, so since I can't see the image at all, I'm running off of calcs that other people did later in the thread. So the laser hits in a circle 20 um across, so let's assume that it digs a hemispherical divot with that radius and that all of the diamond in that hemisphere flashes into plasma of T = 75000 K. Some basic PV = nRT calcs using the molar mass of carbon and the density of diamond gives a pressure of 624 kPa, or six orders of magnitude smaller than diamond's yield strength of 1.6 GPa. There's going to be an explosion, yes, but not one that actually deforms the armor to any extent, and the issue is compounded by the fact that there's not really going to be any containment of that plasma, so the pressure might not even build up to that point, it'll tend to just escape into space. Also, how the hell did you get that plasma temp, RiftandRend ? I don't know how did you get 624 kPa, because I have 181781250 kPa (181 GPa) at 75000 K But assuming your hemisphere, after one nanosecond of exposure, there will be 22160253K (22 MK), and after one microsecond there will be 22160253841K (22 GK), according to my calculation. I also guess that this thing is not carbon anymore, rather a bunch of shredded nuclei in the center of 40 um supernova. Unfortunately I don't know how to calculate these nuclear reactions. I used a molar mass of C = 0.012 kg/mol, density of diamond = 3500 kg/m^3
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Post by newageofpower on Jan 15, 2017 20:09:28 GMT
So you're saying the National Ignition Facility needs a gigantic 50m mirror and frequency quadrupling...
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Post by michalo on Jan 15, 2017 20:38:48 GMT
So you're saying the National Ignition Facility needs a gigantic 50m mirror and frequency quadrupling... These guys are cheating, they have pulse lasers... But it looks like the ray will have to dig a hole in armor to keep particles longer inside beam, because on surface of the armor particles will escape after 1e-10 s and get heated to only 2MK.
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Post by caiaphas on Jan 15, 2017 22:16:30 GMT
That was not at all evident to me in your original post, but I can see what you're saying somewhat in later posts. My apologies. EDIT: Right, so since I can't see the image at all, I'm running off of calcs that other people did later in the thread. So the laser hits in a circle 20 um across, so let's assume that it digs a hemispherical divot with that radius and that all of the diamond in that hemisphere flashes into plasma of T = 75000 K. Some basic PV = nRT calcs using the molar mass of carbon and the density of diamond gives a pressure of 624 kPa, or six orders of magnitude smaller than diamond's yield strength of 1.6 GPa. There's going to be an explosion, yes, but not one that actually deforms the armor to any extent, and the issue is compounded by the fact that there's not really going to be any containment of that plasma, so the pressure might not even build up to that point, it'll tend to just escape into space. Also, how the hell did you get that plasma temp, RiftandRend ? I don't know how did you get 624 kPa, because I have 181781250 kPa (181 GPa) at 75000 K But assuming your hemisphere, after one nanosecond of exposure, there will be 22160253K (22 MK), and after one microsecond there will be 22160253841K (22 GK), according to my calculation. I also guess that this thing is not carbon anymore, rather a bunch of shredded nuclei in the center of 40 um supernova. Unfortunately I don't know how to calculate these nuclear reactions. I used a molar mass of C = 0.012 kg/mol, density of diamond = 3500 kg/m^3 ...bugger, I think I multiplied by the volume instead of dividing. My bad.
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Post by deltav on Jan 25, 2017 8:42:10 GMT
I was arguing that the game has an inaccurate representation of laser damage. Think so? I have no idea... If we assume that all of that energy is transferred to the material in reality, then yes of course the game must be wrong. But if in real life most of the energy of lasers is wasted in heat that is radiated away? Then perhaps not. It's clear that Qswitched thinks not much of lasers as a main ship to ship weapon, but I'm not sure why. I wish (s)he had more time to participate on this blog. Qswitched... "Lasers fill a very specific niche in space warfare, and that is of precision destruction of weakly armored systems at long distances. Lasers are very good at melting down exposed enemy weapons, knocking out their rocket exhaust nozzles, and most importantly, killing drones. While missiles have very few weak points, and can shrug off laser damage with thick plating, drones have exposed weapons and radiators, which makes them very vulnerable to lasers. In terms of actually destroying enemy capital ships, however, lasers can cut into the enemy bulkhead all day with basically zero effect (I measured the ablation of a monolithic armor plate at one point, and found that the ablation was happening at micrometers per second)." childrenofadeadearth.wordpress.com/2016/04/29/misconceptions-about-space-warfare/
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Post by Crazy Tom on Jan 25, 2017 14:02:24 GMT
Remember that the main reasons lasers are so dominant right now is that we built ridiculous nuclear reactors, which may not function IRL. The way I see it, we should verify reactor functionality before coming back to lasers.
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Post by lieste on Jan 25, 2017 15:39:15 GMT
I was fairly disappointed with my high(ish?) intensity (65MW/m^2 at 1Mm) 800MW M3.0 Mm laser. It was excellent against drones and okay against missiles, but wasn't as effective as the railgun it was paired with against the frontal aspect of 'pointy' versions of the stock capitals (or for hard killing them in oblique or side aspect tbh)... I think the issue is that the intensity, which is high enough to burn through the bulkheads in normal impacts is greatly diffused by the shallow angle, and in conjunction with the wander of the aimpoint didn't concentrate enough energy to accomplish much.
Ships died if they flashed their drives at the laser, where the railgun might not be quick enough to capitalise at extreme ranges, but otherwise I only burnt huge voids in the wipple shield and damaged a few of the weaker weapons - killing radiators seemed beyond the capability of the weapon (though I have to wonder how the rad stays attached if it cannot be hit behind/inside the wipple shield and the shield is burnt away from around it?) until the hostile ship has stopped pointing directly at the lasing ship. The remaining guns, and radiators were stripped by railgun fires, and I think most of the hull breeches were caused by impacts on the bare bulkhead by railgun fire rather than laser cutting.
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