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Post by EshaNas on Nov 2, 2017 22:05:10 GMT
As in using some of the antimatter beam core itself tie into power production? I had, admittedly, barely touched that. You use beam core designs, which focuses charged particles out of the nozzle, those particles could be converted into electricity at efficiencies of 90% using Direct Conversion. Ooh, I see. That gives me a lot more juice....
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Post by Kerr on Nov 2, 2017 22:16:11 GMT
You use beam core designs, which focuses charged particles out of the nozzle, those particles could be converted into electricity at efficiencies of 90% using Direct Conversion. Ooh, I see. That gives me a lot more juice.... That gives you death star levels (not quite, but hey, you can sterilize an entire planet in the same time span) for a one megaton ship with "interesting" levels of acceleration.
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Post by matterbeam on Nov 2, 2017 23:56:01 GMT
I though only grazing incidence mirrors are possible at these wavelengths? That's right... it might be a typo on that website. I haven't found such qualities for mirrors from other manufacturers.
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Post by EshaNas on Nov 3, 2017 2:07:37 GMT
Ooh, I see. That gives me a lot more juice.... That gives you death star levels (not quite, but hey, you can sterilize an entire planet in the same time span) for a one megaton ship with "interesting" levels of acceleration. Well not 1 megaton; just something a bit like 10-100 or so range mw range nuclear reactors for a 21st century vessel. Are beam cores really that darn OP? I just selected them because 1) fast and 2) that a new paper came out giving them 12 tesla range magnets, making them far more 'feasible'.
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Post by Kerr on Nov 3, 2017 5:59:57 GMT
That gives you death star levels (not quite, but hey, you can sterilize an entire planet in the same time span) for a one megaton ship with "interesting" levels of acceleration. Well not 1 megaton; just something a bit like 10-100 or so range mw range nuclear reactors for a 21st century vessel. Are beam cores really that darn OP? I just selected them because 1) fast and 2) that a new paper came out giving them 12 tesla range magnets, making them far more 'feasible'. Ah you mean Beamed Core Antimatter propulsion: Engine design and optimization, I analyzed it on here. Short: The performance of the beam core design is 0.265c. 1kg Matter and antimatter gives you 80MN of Thrust, but carry an energy of 3.3e16J or 8 megatons of TNT per. And your upper end 100kT ships have 8m/s of acceleration they will put out roughly 1.5 Tsar bombas per second or just 79MT. And your ship gets 136MT worth of gamma rays. Not that nice. An Pinch Discharge antimatter GeV Laser or an kugelblitz drive might be better.
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Post by Kerr on Nov 3, 2017 20:41:25 GMT
@wtfitsomg: I kind of dislike that guesswork. Either I can get a rough estimate or I just make sure the numbers don't matter. Here's my take on a high power density laser weapon system based on today's technology: Gyrotron-pumped VECSEL. I found the laser to be 10kW/kg and has an efficiency of 50%. However, seeing the performance of frequency doublers, 60% would be a better figure. Personally, I would go for fibre optic lasers. Their lower efficiency (~50%) is largely compensated for by high resistance to heat and simple design. Heat pumps have an efficiency and a coefficient of performance. The former is debatable but values from 35% to 80% have been reported. The latter is defined by the ratio of the hot side temperature to the temperature gradient. So, for example, pumping heat from a 500K source to a 1500K radiator incurs a 1500/1000: 1.5x energy penalty. For each watt you move, you need to feed the heat pumps 1.5W. Then, the intrinsic efficiency comes into play. At 80% efficiency, the heat pump actually needs 1.875W per watt moved. The actual efficiency becomes 53%. If laser weapon webs are a thing in your setting, there is no point in ever having a single massive mirror. You have your laser generator and a 'first link' mirror. This first link connects to an interplanetary network of laser mirrors, or a tactical fleet of mirror drones. Placing a mirror halfway to your target dramatically reduces the total mirror area: the 'first link' mirror only needs to keep the beam spot size smaller than the 'second link' mirror, and the 'second link' mirror only needs to focus across half the distance. The 'first link' can therefore have a massive spot size at the halfway distance. The second link has 1/2^2: 1/4 times less area than a mirror that tries to focus across the entire distance. In total, a simple mirror at halfway might reduce the total mirror area to perhaps 26% of the single-mirror setup! What kind of operating temperatures can I expect with fiber lasers? Fiber lasers are neat, they are simple to cool, have often diffraction-limited beam qualities and are fairly efficient. But that all is quite useless if it only has efficiencies of up to 50% when it is operating at 50° Celsius, which means I'll have to use a lot of heat pumps to keep my radiators relatively small and compact.
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Post by Enderminion on Nov 3, 2017 22:14:06 GMT
are heat pumps even worth it?
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Post by Kerr on Nov 3, 2017 22:24:11 GMT
are heat pumps even worth it? Yes? The lasers ingame are already at a decent temperature, diode pumped lasers can only efficiently operate at room temperature, fiber lasers seem to work at somewhat higher temperatures, gyrotrons require to operate at temperatures where they don't melt into a slag, so maybe 200° C. And for FEL's you want to have cryogenic RF Cavities.
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Post by matterbeam on Nov 5, 2017 17:07:53 GMT
@wtfitsomg: I kind of dislike that guesswork. Either I can get a rough estimate or I just make sure the numbers don't matter. Here's my take on a high power density laser weapon system based on today's technology: Gyrotron-pumped VECSEL. I found the laser to be 10kW/kg and has an efficiency of 50%. However, seeing the performance of frequency doublers, 60% would be a better figure. Personally, I would go for fibre optic lasers. Their lower efficiency (~50%) is largely compensated for by high resistance to heat and simple design. Heat pumps have an efficiency and a coefficient of performance. The former is debatable but values from 35% to 80% have been reported. The latter is defined by the ratio of the hot side temperature to the temperature gradient. So, for example, pumping heat from a 500K source to a 1500K radiator incurs a 1500/1000: 1.5x energy penalty. For each watt you move, you need to feed the heat pumps 1.5W. Then, the intrinsic efficiency comes into play. At 80% efficiency, the heat pump actually needs 1.875W per watt moved. The actual efficiency becomes 53%. If laser weapon webs are a thing in your setting, there is no point in ever having a single massive mirror. You have your laser generator and a 'first link' mirror. This first link connects to an interplanetary network of laser mirrors, or a tactical fleet of mirror drones. Placing a mirror halfway to your target dramatically reduces the total mirror area: the 'first link' mirror only needs to keep the beam spot size smaller than the 'second link' mirror, and the 'second link' mirror only needs to focus across half the distance. The 'first link' can therefore have a massive spot size at the halfway distance. The second link has 1/2^2: 1/4 times less area than a mirror that tries to focus across the entire distance. In total, a simple mirror at halfway might reduce the total mirror area to perhaps 26% of the single-mirror setup! What kind of operating temperatures can I expect with fiber lasers? Fiber lasers are neat, they are simple to cool, have often diffraction-limited beam qualities and are fairly efficient. But that all is quite useless if it only has efficiencies of up to 50% when it is operating at 50° Celsius, which means I'll have to use a lot of heat pumps to keep my radiators relatively small and compact. Fibre optic lasers are pumped by a diode source that can be 70% efficient or more, then converted to a different wavelength and 'corrected' in the fibre optic cables. The overall efficiency falls to 50%. Overall efficiency can be increased if a different pumping source is used, like a gyrotron. The fibre optic lasers can operate at up to 650K when limited to the outer cladding materials' thermal properties. If those materials are replaced, then you are limited by the 1982K melting temperature of the quartz. cdn.intechopen.com/pdfs-wm/49749.pdfSolid state lasers are like modern microelectronics, with ~550K maximum temperature. cdn.intechopen.com/pdfs-wm/40634.pdf
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Post by Kerr on Nov 5, 2017 17:17:19 GMT
What kind of operating temperatures can I expect with fiber lasers? Fiber lasers are neat, they are simple to cool, have often diffraction-limited beam qualities and are fairly efficient. But that all is quite useless if it only has efficiencies of up to 50% when it is operating at 50° Celsius, which means I'll have to use a lot of heat pumps to keep my radiators relatively small and compact. Fibre optic lasers are pumped by a diode source that can be 70% efficient or more, then converted to a different wavelength and 'corrected' in the fibre optic cables. The overall efficiency falls to 50%. Overall efficiency can be increased if a different pumping source is used, like a gyrotron. The fibre optic lasers can operate at up to 650K when limited to the outer cladding materials' thermal properties. If those materials are replaced, then you are limited by the 1982K melting temperature of the quartz. cdn.intechopen.com/pdfs-wm/49749.pdfSolid state lasers are like modern microelectronics, with ~550K maximum temperature. cdn.intechopen.com/pdfs-wm/40634.pdfI've heard about efficiencies of up to 90% for optical-optical/light-light conversion in fiber optics. The point with gyrotron is very interesting as it produces light on a similar wavelength and can apparently operate at much higher temperature which results in much lower heat pump mass costs. Are you sure that the changing the cladding would change the maximum operating temperature? The fiber has to be doped, and the doping material can often only operate at significantly lower temperatures. Side question, you are currently researching particle accelerators? What's the highest electrical-beam efficiency for electron linacs? I've seen some commercial klystrons operating at 65%. Most likely non-superconductive which means operating temperature can be pretty high.
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Post by matterbeam on Nov 5, 2017 17:47:07 GMT
Fibre optic lasers are pumped by a diode source that can be 70% efficient or more, then converted to a different wavelength and 'corrected' in the fibre optic cables. The overall efficiency falls to 50%. Overall efficiency can be increased if a different pumping source is used, like a gyrotron. The fibre optic lasers can operate at up to 650K when limited to the outer cladding materials' thermal properties. If those materials are replaced, then you are limited by the 1982K melting temperature of the quartz. cdn.intechopen.com/pdfs-wm/49749.pdfSolid state lasers are like modern microelectronics, with ~550K maximum temperature. cdn.intechopen.com/pdfs-wm/40634.pdfI've heard about efficiencies of up to 90% for optical-optical/light-light conversion in fiber optics. The point with gyrotron is very interesting as it produces light on a similar wavelength and can apparently operate at much higher temperature which results in much lower heat pump mass costs. Are you sure that the changing the cladding would change the maximum operating temperature? The fiber has to be doped, and the doping material can often only operate at significantly lower temperatures. Side question, you are currently researching particle accelerators? What's the highest electrical-beam efficiency for electron linacs? I've seen some commercial klystrons operating at 65%. Most likely non-superconductive which means operating temperature can be pretty high. I don't know enough about laser dopants to confirm anything. Nonetheless, even at 600K temperature, we get a pretty good laser using modern technologies. For example, at 100MW and 50% overall efficiency, you need to manage 50MW of 600K heat. Pump it up to 1500K and you'll need 75MW to power the heat pumps for an overall power consumption of 175MW for a 50MW beam. Overall, lasers struggle to get both high efficiency and good beam quality.
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Post by Kerr on Nov 5, 2017 17:59:46 GMT
I've heard about efficiencies of up to 90% for optical-optical/light-light conversion in fiber optics. The point with gyrotron is very interesting as it produces light on a similar wavelength and can apparently operate at much higher temperature which results in much lower heat pump mass costs. Are you sure that the changing the cladding would change the maximum operating temperature? The fiber has to be doped, and the doping material can often only operate at significantly lower temperatures. Side question, you are currently researching particle accelerators? What's the highest electrical-beam efficiency for electron linacs? I've seen some commercial klystrons operating at 65%. Most likely non-superconductive which means operating temperature can be pretty high. I don't know enough about laser dopants to confirm anything. Nonetheless, even at 600K temperature, we get a pretty good laser using modern technologies. For example, at 100MW and 50% overall efficiency, you need to manage 50MW of 600K heat. Pump it up to 1500K and you'll need 75MW to power the heat pumps for an overall power consumption of 175MW for a 50MW beam. Overall, lasers struggle to get both high efficiency and good beam quality. Wait, how did you get 75MW needed power to pump 50MW-600K to 1500K? In a Fiber laser the fiber optic acts as the gain medium, that's why they are doped with rare earth metals. Erbium doped fiber seems to work with the quartz cladding, but they produce 3µm light. Ytterbium with 1µm light and 824°C seems to make more sense, so fiber might not have to pump it's heat.
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Post by matterbeam on Nov 5, 2017 18:13:26 GMT
I don't know enough about laser dopants to confirm anything. Nonetheless, even at 600K temperature, we get a pretty good laser using modern technologies. For example, at 100MW and 50% overall efficiency, you need to manage 50MW of 600K heat. Pump it up to 1500K and you'll need 75MW to power the heat pumps for an overall power consumption of 175MW for a 50MW beam. Overall, lasers struggle to get both high efficiency and good beam quality. Wait, how did you get 75MW needed power to pump 50MW-600K to 1500K? In a Fiber laser the fiber optic acts as the gain medium, that's why they are doped with rare earth metals. Erbium doped fiber seems to work with the quartz cladding, but they produce 3µm light. Ytterbium with 1µm light and 824°C seems to make more sense, so fiber might not have to pump it's heat. Heat pump inverse coefficient of performance: (Th-Tc)/Tc = (1500-600)/600 = 1.5 tells me you need 1.5W of pump power to move 1W of waste heat up that gradient.
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Post by Kerr on Nov 5, 2017 18:15:57 GMT
Wait, how did you get 75MW needed power to pump 50MW-600K to 1500K? In a Fiber laser the fiber optic acts as the gain medium, that's why they are doped with rare earth metals. Erbium doped fiber seems to work with the quartz cladding, but they produce 3µm light. Ytterbium with 1µm light and 824°C seems to make more sense, so fiber might not have to pump it's heat. Heat pump inverse coefficient of performance: (Th-Tc)/Tc = (1500-600)/600 = 1.5 tells me you need 1.5W of pump power to move 1W of waste heat up that gradient. I see, thanks. Do you have something about the electron linac efficiency subject?
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Post by matterbeam on Nov 5, 2017 19:09:19 GMT
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