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Post by Kerr on Nov 5, 2017 19:18:51 GMT
Thanks for the first one, already knew the second one. Ok, the first didn't really helped, I don't know if they mean electrical to beam efficiency with "electrical efficiency". The second, yeah, good to know that such high amounts are possible, but I don't know if it is for superconducting RF accelerators or "normal" ones, and if the latter what operating temperature? My current calculation show me that an Gyrotron-Fiber Laser with two 88% efficient frequency doublers operating at 25°C or ~300K produce an wall-plug efficiency of 25% while operating at 1500K, and an specific power of 1.25MW/ton. Beam quality factor should be around 1.5, commercial fiber lasers already achieve 1.3 and below. Plus a nice 250nm frequency. |
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Post by matterbeam on Nov 5, 2017 20:38:00 GMT
Thanks for the first one, already knew the second one. Ok, the first didn't really helped, I don't know if they mean electrical to beam efficiency with "electrical efficiency". The second, yeah, good to know that such high amounts are possible, but I don't know if it is for superconducting RF accelerators or "normal" ones, and if the latter what operating temperature? My current calculation show me that an Gyrotron-Fiber Laser with two 88% efficient frequency doublers operating at 25°C or ~300K produce an wall-plug efficiency of 25% while operating at 1500K, and an specific power of 1.25MW/ton. Beam quality factor should be around 1.5, commercial fiber lasers already achieve 1.3 and below. Plus a nice 250nm frequency. What figures did you use for specific power? How did you get that M2 beam quality factor? My understanding is that fibre optic lasers regularly are able to produce diffraction limited lasers (M2=1). You also need to get total internal refraction within the tube. This might be harder to do with shorter wavelengths. I look into some figures to share with you for electron beam accelerators. |
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Post by dichebach on Nov 6, 2017 2:29:24 GMT
How fast could a "school bus-sized" or "destroyer-sized" object be propelled (using the tech in the game/near future)? 50km/s 100km/s? Given the lack of atmosphere on any of the rocks on which people are living in this game, seems to me, that long-distance bombardment with high velocity slugs would bring most "wars" to an end pretty quick. Why bother making space ships when you can just build a few massive EM guns that launch enormous chunks of metal at your enemies bases. Get the 100 or 200 platforms that you need (which could easily be hidden) all setup, and distribute an order for each gun to initiate firing on its pre-determined targets at a predetermined galactic relative time: Boom*200, no more enemy . . . at all . . . their bases and shipyards and farms turned to dust. I don't have the knowledge to have the gut instinct for how much mass and velocity it would take for a projectile to wipe out 150m people living on Luna, but based on past fiddling with this app www.purdue.edu/impactearth/. . . and the fact that only Mars would afford some degree of real protection from such a bolide (by virtue of its thin atmosphere), I'm guessing "warfare" in the sense of ship-to-ship engagements would never happen, at least not within the ecological framework presented in the game. Not exactly the point of this thread, but a point that crossed my mind in reading the highly detailed technical discussions of ship-to-ship stuff over the last couple pages. |
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Post by Kerr on Nov 6, 2017 5:57:50 GMT
Thanks for the first one, already knew the second one. Ok, the first didn't really helped, I don't know if they mean electrical to beam efficiency with "electrical efficiency". The second, yeah, good to know that such high amounts are possible, but I don't know if it is for superconducting RF accelerators or "normal" ones, and if the latter what operating temperature? My current calculation show me that an Gyrotron-Fiber Laser with two 88% efficient frequency doublers operating at 25°C or ~300K produce an wall-plug efficiency of 25% while operating at 1500K, and an specific power of 1.25MW/ton. Beam quality factor should be around 1.5, commercial fiber lasers already achieve 1.3 and below. Plus a nice 250nm frequency. What figures did you use for specific power? How did you get that M2 beam quality factor? My understanding is that fibre optic lasers regularly are able to produce diffraction limited lasers (M2=1). You also need to get total internal refraction within the tube. This might be harder to do with shorter wavelengths. I look into some figures to share with you for electron beam accelerators. 10kW/kg Laser elements, 1kW/kg Heat pumps. Wikipedia, Luke Campbell and product information for commercial fiber lasers. Apparently only in theory, and a bit of pessimism doesn't hurt either. That would be nice from you, beam quality is often related to operating temperature of lasing elements, if my laser in its entirety runs at an average of 100K would I achieve diffraction-limited beams? Based on a 90% SRF Klystron and 99.9% Recovery Linac I would get 900MW Laser energy from 1GW, 100MW waste heat which has to be pumped to 1500K using 1750MW of power, wall-plug of roughly 36% and apparently difffraction-limited beams with frequencies as low as there are efficient mirrors/lenses for it. |
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Post by Enderminion on Nov 6, 2017 13:26:03 GMT
How fast could a "school bus-sized" or "destroyer-sized" object be propelled (using the tech in the game/near future)? 50km/s 100km/s? Given the lack of atmosphere on any of the rocks on which people are living in this game, seems to me, that long-distance bombardment with high velocity slugs would bring most "wars" to an end pretty quick. Why bother making space ships when you can just build a few massive EM guns that launch enormous chunks of metal at your enemies bases. Get the 100 or 200 platforms that you need (which could easily be hidden) all setup, and distribute an order for each gun to initiate firing on its pre-determined targets at a predetermined galactic relative time: Boom*200, no more enemy . . . at all . . . their bases and shipyards and farms turned to dust. I don't have the knowledge to have the gut instinct for how much mass and velocity it would take for a projectile to wipe out 150m people living on Luna, but based on past fiddling with this app www.purdue.edu/impactearth/. . . and the fact that only Mars would afford some degree of real protection from such a bolide (by virtue of its thin atmosphere), I'm guessing "warfare" in the sense of ship-to-ship engagements would never happen, at least not within the ecological framework presented in the game. Not exactly the point of this thread, but a point that crossed my mind in reading the highly detailed technical discussions of ship-to-ship stuff over the last couple pages. Lasers not mass drivers, lasers have more uses then war or shifting materials then mass drivers and don't need ammo |
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Post by jtyotjotjipaefvj on Nov 6, 2017 15:36:08 GMT
What figures did you use for specific power? How did you get that M2 beam quality factor? My understanding is that fibre optic lasers regularly are able to produce diffraction limited lasers (M2=1). You also need to get total internal refraction within the tube. This might be harder to do with shorter wavelengths. I look into some figures to share with you for electron beam accelerators. 10kW/kg Laser elements, 1kW/kg Heat pumps. Wikipedia, Luke Campbell and product information for commercial fiber lasers. Apparently only in theory, and a bit of pessimism doesn't hurt either. That would be nice from you, beam quality is often related to operating temperature of lasing elements, if my laser in its entirety runs at an average of 100K would I achieve diffraction-limited beams? Based on a 90% SRF Klystron and 99.9% Recovery Linac I would get 900MW Laser energy from 1GW, 100MW waste heat which has to be pumped to 1500K using 1750MW of power, wall-plug of roughly 36% and apparently difffraction-limited beams with frequencies as low as there are efficient mirrors/lenses for it. Are you sure spending so much energy on heat pumps makes sense? If the reactors work at 16% efficiency doable in-game, even at 2500K exit temperature the radiator footprint for the reactor is going to be pretty big, and the extra 1.75 GW in power production is going to cost quite a lot of money and mass as well. It might make sense to stay at lower temperatures even if that means the laser radiator has to be bigger. Of course, the fourth power of temperature in radiator efficiency might mean higher temperature is always better, but I wouldn't blindly assume so without checking. It should be fairly simple to choose optimal output temperature for the laser while taking into account the added mass from reactors and radiators needed to run the heat pumps as well as the laser itself. |
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Post by Kerr on Nov 6, 2017 15:48:23 GMT
10kW/kg Laser elements, 1kW/kg Heat pumps. Wikipedia, Luke Campbell and product information for commercial fiber lasers. Apparently only in theory, and a bit of pessimism doesn't hurt either. That would be nice from you, beam quality is often related to operating temperature of lasing elements, if my laser in its entirety runs at an average of 100K would I achieve diffraction-limited beams? Based on a 90% SRF Klystron and 99.9% Recovery Linac I would get 900MW Laser energy from 1GW, 100MW waste heat which has to be pumped to 1500K using 1750MW of power, wall-plug of roughly 36% and apparently difffraction-limited beams with frequencies as low as there are efficient mirrors/lenses for it. Are you sure spending so much energy on heat pumps makes sense? If the reactors work at 16% efficiency doable in-game, even at 2500K exit temperature the radiator footprint for the reactor is going to be pretty big, and the extra 1.75 GW in power production is going to cost quite a lot of money and mass as well. It might make sense to stay at lower temperatures even if that means the laser radiator has to be bigger. Of course, the fourth power of temperature in radiator efficiency might mean higher temperature is always better, but I wouldn't blindly assume so without checking. It should be fairly simple to choose optimal output temperature for the laser while taking into account the added mass from reactors and radiators needed to run the heat pumps as well as the laser itself. Seriously, I am not talking about any of the ingame lasers with their nicely high output temperatures. Contrary to what player-made lasers like Apophys ones makes you believe, arc lamp pumped lasers are actually horrible, not just efficiency, but beam quality and mass are also horrible, and something like 800K 100% frequency doublers even though real life state of the art frequency doublers achieve 88% at 25°C just make matters worse. Room-temperature radiators? Cryogenic radiators? 600K radiators with M² of 5.7? Either CDE stock lasers (ok not that bad) or heat pumps, take your poison. |
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Post by jtyotjotjipaefvj on Nov 6, 2017 15:57:03 GMT
Are you sure spending so much energy on heat pumps makes sense? If the reactors work at 16% efficiency doable in-game, even at 2500K exit temperature the radiator footprint for the reactor is going to be pretty big, and the extra 1.75 GW in power production is going to cost quite a lot of money and mass as well. It might make sense to stay at lower temperatures even if that means the laser radiator has to be bigger. Of course, the fourth power of temperature in radiator efficiency might mean higher temperature is always better, but I wouldn't blindly assume so without checking. It should be fairly simple to choose optimal output temperature for the laser while taking into account the added mass from reactors and radiators needed to run the heat pumps as well as the laser itself. Seriously, I am not talking about any of the ingame lasers with their nicely high output temperatures. Contrary to what player-made lasers like Apophys ones makes you believe, arc lamp pumped lasers are actually horrible, not just efficiency, but beam quality and mass are also horrible, and something like 800K 100% frequency doublers even though real life state of the art frequency doublers achieve 88% at 25°C just make matters worse. Room-temperature radiators? Cryogenic radiators? 600K radiators with M² of 5.7? Either CDE stock lasers (ok not that bad) or heat pumps, take your poison. I think you missed my point. I'm saying that when you use heat pumps, the choice of output temperature affects power requirements, therefore affecting how large radiators your reactor needs. Based on a quick test using CDE 16% efficiency reactors, it seems you get minimal radiator area close to 1200 K output temperatures after pumping, if you use the laser in your example (1 GW power, 100 MW waste heat, 100 K exit temperature) Here's the calculator I used: google drive link |
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Post by Kerr on Nov 6, 2017 16:26:59 GMT
Seriously, I am not talking about any of the ingame lasers with their nicely high output temperatures. Contrary to what player-made lasers like Apophys ones makes you believe, arc lamp pumped lasers are actually horrible, not just efficiency, but beam quality and mass are also horrible, and something like 800K 100% frequency doublers even though real life state of the art frequency doublers achieve 88% at 25°C just make matters worse. Room-temperature radiators? Cryogenic radiators? 600K radiators with M² of 5.7? Either CDE stock lasers (ok not that bad) or heat pumps, take your poison. I think you missed my point. I'm saying that when you use heat pumps, the choice of output temperature affects power requirements, therefore affecting how large radiators your reactor needs. Based on a quick test using CDE 16% efficiency reactors, it seems you get minimal radiator area close to 1200 K output temperatures after pumping, if you use the laser in your example (1 GW power, 100 MW waste heat, 100 K exit temperature) Here's the calculator I used: google drive linkI see your point now. How does this change if you use non CDE reactors? Using 10MW/t benchmarks plus 40-60% efficient turbines/MHD? |
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