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Using radio waves to heat, and electromagnetic fields to contain....could methane be heated to much higher temperatures than via simple oxygen/combustion, thus producing a much higher specific impulse for, say, a rocket engine?

Not talking plasma drive temps here (millions of degrees), but several thousand degrees above normal combustion temperature.

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put on hold as unclear what you're asking by Mithoron, Mathew Mahindaratne, Todd Minehardt, M.A.R. ಠ_ಠ, Nilay Ghosh Jan 13 at 18:06

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  • $\begingroup$ There are lots of methods of production of plasma and it's containment, but I don't see a reason to ask about it here... $\endgroup$ – Mithoron Jan 11 at 23:45
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    $\begingroup$ Thank you. I apologize. I am not a student, and have no educational background in chemistry at all. I found this site, and was curious as to potential methods to get better, more efficient thrust from earth to orbit propulsion systems. $\endgroup$ – david vanriper Jan 12 at 1:13
  • $\begingroup$ Beside all, when a rocket eject exhaust is ejecting what it has brought up. In your case the gas would be simply a medium. How would you power your radio waves of whatever system heats up the methane? That would be the true specific impulse. Either you fall in alternative engine as the plasma drive category and regime of application or is better to burn the fuel. Power regimes differ a lot. $\endgroup$ – Alchimista Jan 12 at 12:18
  • $\begingroup$ I'm voting to close this question as off-topic because it's rather plasma physics/propulsion stuff. $\endgroup$ – Mithoron Jan 12 at 15:18
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    $\begingroup$ Methane decomposes to hydrogen and carbon at high temperatures. $\endgroup$ – aventurin Jan 13 at 11:03
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The problem is where the energy for heating comes from not the gas or the mechanism of heating

Rocket engines often use burning fuels to produce thrust because chemicals are a very good store of energy and burning often produces hot gaseous products.

Yes, you can produce hot gases by other means (there are electrically driven plasma rockets and you could, maybe, heat gases with microwaves or similar radiation). But the problem you have is where to get the energy for that process? A self-contained rocket has to have an energy source and that source has to be compact and a slight as possible (a long electrical cord to an electric socket isn't practical in orbit or in space). Just about the best way to store energy is various combinations of reactive chemicals (eg oxygen and kerosine) and the easiest way to turn that into thrust is burning. The only other approach know to work well is to put a nuclear reactor on the rocket as an energy source but that has obvious disadvantages for other reasons.

Rocket scientists have spent a lot of heroic effort to optimise mixtures of (often dangerous) chemicals to achieve better thrust. For a good summary read John D Clark's Ignition where he traces the history of trying to make use of extreme oxidising agents like chlorine trifluoride to get better performance.

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