Energy transfer during gas discharge

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Discussion Overview

The discussion revolves around the mechanisms of energy transfer during gas discharge, specifically comparing the role of electron kinetic energy versus the electric field in energy propagation. Participants explore the velocities of electrons in different contexts, such as electric current and gas discharge, and question the implications of these velocities on energy transfer mechanisms.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant states that energy propagates through the field near a wire during electric current, while questioning if energy transfer during gas discharge occurs via electron kinetic energy due to higher electron velocities.
  • Another participant seeks clarification on the electron velocity figures, suggesting a possible error in the exponent of the stated velocity during gas discharge.
  • A subsequent reply confirms an error in the exponent, correcting the electron velocity to 10^[6] m/s.
  • Another participant questions whether the corrected value refers to drift velocity or thermal velocity, emphasizing the relevance of the distinction for charge transport in electric current.
  • A later contribution references a scientific article discussing electron flux and energy estimates during gas discharge, noting that electrons can reach energies of approximately 100 eV, which corresponds to high velocities.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the correct interpretation of electron velocities and their implications for energy transfer mechanisms. Multiple competing views remain about the nature of the velocities discussed and their relevance to the topic.

Contextual Notes

There are unresolved questions about the definitions of drift and thermal velocities, as well as the implications of the stated electron velocities for energy transfer in gas discharge. The discussion references specific scientific literature but does not reach a consensus on the interpretations of the data presented.

user-000
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It is known that while the electric current flows along the wire the energy propagates through the field near that wire (and not by means of electron gas kinetic energy) and the electrons' velocity is equal approximately to 10^[-3] m/s.

Meanwhile, the electrons' velocity during the gas discharge can be as high as 10^[-6] m/s.
Does that mean that the energy transition in the case of gas discharge occurs via electrons' kinetic energy and not the field?
 
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Welcome to PF.

user-000 said:
Meanwhile, the electrons' velocity during the gas discharge can be as high as 10^[-6] m/s.
Do you mean "as low as", or do you have a sign error in the exponent? Can you post links to the source of your information on these numbers? Thanks.
 
berkeman said:
Welcome to PF.


Do you mean "as low as", or do you have a sign error in the exponent? Can you post links to the source of your information on these numbers? Thanks.
Oh, I'm sorry, it is an error in exponent. I meant 10^[6]
 
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Are you sure that the 106 is the drift velocity of the electrons and not the thermal velocity? What is the source of this value? The thermal velocity of free electrons in a metal is of the same
order of magnitude (105-106m/s ) but this is not relevant for the charge transport in electric current.
 
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nasu said:
Are you sure that the 106 is the drift velocity of the electrons and not the thermal velocity? What is the source of this value? The thermal velocity of free electrons in a metal is of the same
order of magnitude (105-106m/s ) but this is not relevant for the charge transport in electric current.
The 3rd section of https://sciencejournals.ru/view-article/?j=fizplaz&y=2020&v=46&n=2&a=FizPlaz2002011Shibkov says: "dependences of the electron flux to the collector I4 at the breakdown stage on the distance between the anode and collector at helium pressure of 0.15 Torr and different values of the pulse voltage applied to the discharge gap are presented. Measurements were made on the amplitude value of the beam current to the collector. It can be seen that the flux of electrons that passed through the anode and got into the equipotential space between the second grid and the collector is weakened due to elastic and inelastic collisions with atoms. From the data of Fig. 2, we can find the effective scattering length of the electrons and estimate their energy. It follows from such estimates that at the initial stage at threshold values of U0, electrons with energy ~20 eV predominate in the discharge, and with increasing U0, the energy of electrons increases and reaches the value of ~100 eV at U0 = 700 V."

For an electron 100 eV of the kinetic energy is ~10⁶ m/s
 

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