Moreno Posted November 18, 2017 Share Posted November 18, 2017 Is plasma heated to 2000-3000 C and composed of H+ and OH- ions equilibrium or non equilibrium plasma? Link to comment Share on other sites More sharing options...
John Cuthber Posted November 18, 2017 Share Posted November 18, 2017 Non equilibrium Why do you ask? Link to comment Share on other sites More sharing options...
Moreno Posted November 18, 2017 Author Share Posted November 18, 2017 8 hours ago, John Cuthber said: Non equilibrium Why do you ask? Why exactly? I'm interested in MHD generators. How we define equilibrium or non-equilibrium plasma? Link to comment Share on other sites More sharing options...
John Cuthber Posted November 18, 2017 Share Posted November 18, 2017 At only 3000 degrees the water wouldn't be fully dissociated. Even if it were, there would be other products- notably the neutral H2 and O2 molecules, and their ions and radicals like OH. Having only 2 products would be a very odd state of affairs; the equilibrium would be different. Do you understand this sort of thing? https://en.wikipedia.org/wiki/Chemical_equilibrium https://en.wikipedia.org/wiki/Anisothermal_plasma Link to comment Share on other sites More sharing options...
Moreno Posted November 20, 2017 Author Share Posted November 20, 2017 (edited) On 11/18/2017 at 5:22 PM, John Cuthber said: At only 3000 degrees the water wouldn't be fully dissociated. Even if it were, there would be other products- notably the neutral H2 and O2 molecules, and their ions and radicals like OH. Having only 2 products would be a very odd state of affairs; the equilibrium would be different. Do you understand this sort of thing? https://en.wikipedia.org/wiki/Chemical_equilibrium https://en.wikipedia.org/wiki/Anisothermal_plasma Usually, it is claimed that An Anisothermal plasma has very hot electrons and much "cooler" ions. Quote Examples of anisothermal plasmas can be found among low-pressure plasmas that are excited by high frequency electric fields, see frequency classification of plasmas. They generally exhibit hot electrons that are powered by the alternating electric field, and a neutral and ion component, which is significantly colder due the low efficiency of the energy transfer between light electrons and heavy neutrals and ions. https://en.wikipedia.org/wiki/Anisothermal_plasma Quote In non-equilibrium plasma, the heavy particle temperature is much lower than the electron temperature. https://www.comsol.com/blogs/thermodynamic-equilibrium-of-plasmas/ However, I'm not sure if 2000-3000 C dissociated water has many free electrons. We need to have much higher temperatures (more than 10.000 C) to ionize water. But dissociated water consists of H+ and OH- ions, mostly. Is there too large difference between H+ and OH- ion temperatures to talk about non-equilibrium plasma? Edited November 20, 2017 by Moreno Link to comment Share on other sites More sharing options...
John Cuthber Posted November 20, 2017 Share Posted November 20, 2017 A plasma composed of just H+ and OH- ions would be a very weird plasma. It's a very long way from any equilibrium. Link to comment Share on other sites More sharing options...
Moreno Posted November 20, 2017 Author Share Posted November 20, 2017 48 minutes ago, John Cuthber said: A plasma composed of just H+ and OH- ions would be a very weird plasma. It's a very long way from any equilibrium. Why? Link to comment Share on other sites More sharing options...
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