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19-Year-Old Makes Homemade Solar Death Ray
An anonymous reader writes "Concentrated solar power has the potential to generate immense amounts of energy — but it can also be amazingly destructive. American student Eric Jacqmain has assembled over 5,800 mirrors into his own parabolic 'solar Death Ray'."
Looks like the mythbusters can redo this myth one more time.
Solar power does not "generate" energy. Energy is liberated by conversion from mass through nuclear reactions in the Sun. Solar power collects and transforms radiant energy into heat and then into useful work, like burning something up.
Well I did warn you, you didn't have to read it!
Like ~2,000 years ago. Talk about an old story.
vos nescitis quicquam, nec cogitatis quia expedit nobis ut unus moriatur homo pro populo et non tota gens pereat.
5800 mirrors, the size of fingernails. Glued on an already parabolic disc.
He used an old satellite dish.
Couldn't he just have spray canned it with some reflective paint??
Or glued aluminum foil over it. Or chrome plated it. He chose the most cumbersome way. Everyone who works cutting glass gets some nicked fingers from time to time, imagine cutting 5800 tiny pieces.
I imagined at least 10x10cm mirrors. Now that would have been "solar power".
True, if there had been 5800 10x10cm mirrors. For the same surface size, the smallest the mirrors are the better focus he will get. Ideally, the surface should have an infinite number of infinitely small mirrors, i.e. it would be a smooth parabolic surface.
More specifically, there are two issues with your suggestion. Firstly, lasers are not power-limited by input light, but rather by the design of the lasing cavity and how efficiently it stimulates further emission. Many types do need a decent kick to get them going, but beyond that a bright source offers little or no benefit.
Secondly, even if more input light was useful, this mirror doesn't actually provide that much power. It's just the use of the parabolic reflector to concentrate the energy into a small energy that makes it look impressive. Looking at the dish, it's a few square metres in area, at most. That's only a few kW of light in total, of which only a tiny portion is at any one wavelength which would be useful for pumping a laser. An appropriate pump laser or even a decent flashlamp would be vastly better than this for stimulating laser emission.
Also, LASER. Light Amplification by Stimulated Emission of Radiation.
The tiny mirror pieces are from a mirror ball. Yes, I actually do go out sometimes.
It's already in use - arrays of mirrors all pointing at a tower. The heat melts salt (which requires 538C minimum) which is then used to power steam generators.
http://en.wikipedia.org/wiki/Solar_thermal_energy#Power_tower_designs
Please consider this account deleted, I just can't be bothered with the spam anymore.
You're retarded, small focused flat mirrors are more efficient and less prone to scatter than a non perfect parabolic shape. Not to mention the reflectivity of actual mirror is far superior to any sprays or sheeting you could cheaply purchase. There is a reason the cells of production solar plants use flat mirrors that they combine to form a parrabolic array.
And, bearing that size in mind, a quick back of the envelope suggests that 1 MW is the input power of the light, not the delivered power of the laser. A quick search doesn't turn up any papers or detailed articles relating to this solar tower specifically, but other examples of such solar-pumped NdYAG lasers suggest a conversion efficiency of about 10 W laser power/m^2 of mirror, or about 1% of the incident radiation [1].
So, assuming that lasing efficiency for this system, this is not a 1 MW CW laser, but a 10 kW CW laser pumped with over a megawatt of input power, which necessitates significant cooling to keep the thing from melting. Compared to traditional laser designs, this is still not that impressive, especially given the effort involved in its manufacture.
[1] A solar-pumped Nd:YAG laser in the high collection efficiency regime