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I have a theoretical question, if we use some sort of ionizing radiation like an ionizing laser for example (https://en.wikipedia.org/wiki/Atmospheric-pressure_laser_ionization), to create a path in the air and have a high density electric source right next to where the laser was fired from as to create a path and a gradient for electricity to flow to our target?

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  • $\begingroup$ It's an interesting question and there are probably designs and patents for stun guns based on this technique but I am not sure how this relates to Space Exploration (what to ionize in space?). There are almost 200 SE sites to choose from! If you have a specific space application, then you should add it. If not, consider looking in Physics SE or Electronics SE or especially Worldbuilding SE for similar questions and their answers. $\endgroup$
    – uhoh
    Jan 11 at 4:59
  • $\begingroup$ I think you can sit tight and wait for this to be migrated, probably Worldbuilding is the best place for an open-ended "Is this possible" question. The other sites would demand a more specific question, like "what are the technical challenges" or "how much power could you transfer over say 1 kilometer using a 100 watt laser to ionize?" $\endgroup$
    – uhoh
    Jan 11 at 5:00
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    $\begingroup$ "to create a path in the air" – There is a problem with that: there is no air in space. $\endgroup$ Jan 11 at 10:56
  • $\begingroup$ Well I was thinking to use this as a method of transferring electricity to an electric shuttle or space craft as it is ascending. but sure it could be used for other purposes as well $\endgroup$ Jan 11 at 16:03
  • $\begingroup$ @ZmelgarK1R3D2 if an aircraft of spacecraft has photovoltaic cells, then the laser's light can be converted directly to electricity much much more efficiently. No need to send electricity. Search for "laser powered drone" for example. $\endgroup$
    – uhoh
    Jan 11 at 21:43
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To transfer electrical energy from ground to target, a closed circuit is needed. The current should flow in a closed loop from the source to the load and back needing two paths with an insulation between the conductors.

Using two beams would require a large insulation gap between them to avoid a short circuit between both beams.

But the efficiency would be very low. The resistance of the long ionized path is not negligible small. So less than 5 % of the power may be used by the target and more than 95 % would be wasted within the ionized paths.

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  • $\begingroup$ With two beams you may have the closed-circuit path... $\endgroup$
    – xxavier
    Jan 11 at 7:57
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    $\begingroup$ "The resistance of the ionized path is much greater than the resistance of a copper conductor". My googling leaves much to be desired, but seem to indicate the resistance through a fully ionized air channel(such as inside a lightning strike) is on the same order as a similar volume of metal, and about 3 orders magnitude less than the same mass of metal. $\endgroup$ Jan 11 at 12:20
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    $\begingroup$ @CuteKItty_pleaseStopBArking resistance is proportional to length and inversely proportional to cross sectional area, it doesn't really make sense to relate it to a volume. Anyway, the effectiveness of arc welding and arc furnaces indicates the resistance is high enough that a majority of the power is dissipated in even a short arc, despite the current path including copper cables that are of similar cross section and much greater length. $\endgroup$ Jan 11 at 15:46
  • $\begingroup$ Likely get better efficiency using a non-ionizing laser and a photovoltaic... $\endgroup$
    – Jon Custer
    Jan 11 at 15:58
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    $\begingroup$ @ZmelgarK1R3D2 First, to use the hydraulic analogy, voltage is like pressure and current is like flow rate. Containing a high voltage takes good insulation, conducting a high current takes a low-resistance conductor. Transmitting electrical power requires both. Second, if you're starting outside the atmosphere, you don't have air to ionize. Electrolasers are a real concept, but they are totally useless for power transmission, especially from space. As Jon Custer said, you'd be far better off just using a laser to transmit the power. $\endgroup$ Jan 11 at 20:35

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