The discussion revolves around the electrical resistivity and conductivity of metal vapors, specifically Caesium and Potassium, under various conditions. Participants explore the theoretical and practical aspects of electrical conduction in these vapors, including the necessary conditions for ionization and the implications for applications such as electric motors.
Participants express differing views on the electrical properties of metal vapors, with some asserting that they are insulators while others suggest they can conduct under specific conditions. The discussion remains unresolved regarding the feasibility of using metal vapors in practical applications like electric motors.
Participants note the importance of various conditions such as pressure and ionization for electrical conduction in metal vapors, but these conditions are not fully explored or quantified. The discussion also highlights the complexity of maintaining a conductive state in gases compared to solid conductors.
This discussion may be of interest to those exploring advanced materials for electrical applications, researchers in plasma physics, and individuals considering innovative designs in electrical engineering.
You are right. I should have been more specific. Let's assume that under the proper conditions (Pressure, ionizing radiation, etc..) we have conduction. What is the highest electrical conductivity ever recoded? for both potassium and casesium vapor?DaveE said:Presumably you mean a plasma? The gas must be ionized to conduct. In any case, you have left out sooooo many variables (hint: gas pressure is one). Maybe if you googled "Paschen's law" that would help. Except in the high current region (roughly, completely ionized) it is very non-linear.
It looked to me like there was a lot of information out there: "Cesium vapor discharge", for example. Here's one from the 1930's: https://nvlpubs.nist.gov/nistpubs/jres/21/jresv21n5p697_A1b.pdf
Under the proper conditions (pressure, radiation) this metal vapor becomes electrically conductive.phyzguy said:I believe a neutral gas is an electrical insulator, regardless of whether the atoms composing the gas are metals or non-metals. What would be the mechanism for electrical conduction?
Why would someone do that experiment? I don't think you'll find it.andrew_bak said:You are right. I should have been more specific. Let's assume that under the proper conditions (Pressure, ionizing radiation, etc..) we have conduction. What is the highest electrical conductivity ever recoded? for both potassium and casesium vapor?
DaveE said:Why would someone do that experiment? I don't think you'll find it.
Anyway, it is well known that you can have a negative resistance behavior in some gas discharge configurations. That is why fluorescent lights have ballasts, for example. I find the questions about negative conductivity confusing. What do you really want to know
My question might be a bit confusing. I thought some one may have conducted this experiment out there. Considering that metal vapors are very light weight relative to solid copper wires: I thought why not design an electric motor where instead of rotor windings made of copper you have tubes filled with this metal vapor. By doing so, the rotor would be substantially lighter and thus the motor might rotate faster or less energy will be wasted. That's why I want to know the electrical conductivity of metal vapors at suitable conditions. I am fully aware that there are metals that are far lighter than copper (aluminum) but why not go even lighter? What conductive gases experience positive resistance behavior? Potassium or Caesium vapors don't experience that? Thank you for taking the time to answer...DaveE said:Why would someone do that experiment? I don't think you'll find it.
Anyway, it is well known that you can have a negative resistance behavior in some gas discharge configurations. That is why fluorescent lights have ballasts, for example. I find the questions about negative conductivity confusing. What do you really want to know?
I should have been more specific and called it plasma. You're right. When i said "tube" I meant that the tube would be made of material that is not electrically conductive. But considering the difficulty of keeping the gas in a conductive plasma state I can see the obstacles now. Thank you for your reply.DaveE said:Solid copper will always be much more conductive than ionized gasses. Nearly all of the current in your motor windings will flow through the copper tube. This is assuming that you can keep the gas ionized inside the tube, which will be extremely difficult. Your motor will cost too much to make and perform poorly compared to "normal" designs.
"What conductive gases experience positive resistance behavior?" All of them. BTW, there aren't any conductive gasses, I think you mean plasma.