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Good point about the space elevator issue. I think that it wouldn't take very many positive lightning bolts to foil the idea unless the cable thickness was enor
by ohiovr 6y ago
Good point about the space elevator issue. I think that it wouldn't take very many positive lightning bolts to foil the idea unless the cable thickness was enormous. I recall a conversation (may have been here) about this topic of using wires and light beams to electrically reach the upper atmosphere. NASA did an experiment with a long wire to draw down electricity from the upper atmosphere. Unfortunately the wire melted. I can imagine what they were up to.
Then there was another experiment using an ultra high power laser to do what I proposed above except using uv radiation (which is clearly ionizing), instead of microwaves (which ordinarily are never ionizing). From reading discussions about plasma in tokamaks and polywells I understand that plasma can indeed form with enough heat from gyrotrons. Lasers are just not powerful enough to make a long enough plasma lightning rod. The researchers who used the laser were successful at triggering lightning between clouds. My contribution is "maybe gyrotrons are powerful / more effective".
In SciFi and Acadamia there is tremendous interest in high power non chemical propulsion. In the past it has centered on nuclear energy. The problem with it is the thermal nature of it and the difficulty of scaling it to powers we have on earth. In the air and in space it is challenging to exchange waste heat.
But the ironic thing to me is that ultra high energy is around us all the time if we only knew what to do with it. It is over the earth, in the Van Allen Belts, in solar wind, it is even in the magnetic field of the sun.
- Kaibeezy 6y agoI hope you carry on with this line of thinking, and if you make progress please post, or if you want to discuss feel free to ping me. Just don’t set the atmosphere on fire, Dr. Oppenheimer ;)
- ohiovr 6y agoLol, that's a good one. The chances of a resonance cascade are very small...
- ohiovr 6y agoI found this article: https://news.ycombinator.com/item?id=20931499 https://news.ycombinator.com/item?id=20931499 Looks like someone may have been around this concept a lot longer than I have. But for radio reception, not for long distance atmospheric discharge channeling. I think the solenoid / filament idea is simply untenable due to the enormous amount of power concentrated in them (a coil would simply vaporize). A much more straightforward idea would be to use an open ended tube capped on one side (with shielding) that is lined on the top and bottom with graphite conductors, in a configuration you might find in a rail gun. Graphite is used as I am hoping some of the crazy thermal issues may be better handled with ablation instead of active cooling. Think of a railgun tube being like a combustion chamber. There may be some advantages to including an magnetic expansion nozzle. Liquid propellant (liquid methane for example) could be injected inside and when the lightning comes in contact with the top and bottom rails massive amounts of current flow and thoroughly ionize the propellant. Huge Lorenz forces from the multi kilo-amp / mega-volt discharge develop in the conductive plasma blasting it out at around. An electromagnetic sheath might be advantageous to keep the hot plasma from pressing too hard on the tube / rails conducting away energy. Exhaust velocity can be tuned depending on needs during boost. On the low end, 200 kilograms could impart ~1000000 newtons of thrust at an exhaust velocity of about 7km/s. On the high end 2 kg of propellant could yield ~100000 newtons, 1/10th the trust but 10 times the specific impulse. Of course these are just rough calculations in very ideal circumstances.