please tell me regarding making air plasma via air ionization, if air is ionized with an negative air ionizer; i.e. making the air rich in electrons. at which point would the air be called a plasma?
would it be a gradual process that would gradually increase the conductivity of the air or is there a defined point?
Answer Well the definition of a plasma is actually quite as complex set of criteria. You're kind of talking about charged air and not just a plasma, plasma in bulk is actually generally neutral. A charge difference buildup causing air to ionize light lightning could be a sudden discharge, causing a plasma. Air could be microwaved until it causes a plasma. A discharge tube can make a plasma of air. If you're looking for a "defined point" for a plasma, then it depends on the level of ionization, the density of the air, and the size of the plasma. This is actually covered surprisingly well on wikipedia, see here: http://en.wikipedia.org/wiki/Plasma_(physics)#Definition I checked with other sources, this is a pretty general description that someone who works in the field might argue with to a degree...but as a general set of criteria it actually holds water pretty well and doesn't require you to be subscribed through a library to special journals or references. Check it out.
I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.
I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.
Education/Credentials Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.