# Air ionization temperature

1. Oct 14, 2012

### thepowdertoy

Need help here to determine correct temperature when the air turned into plasma, because there is someone in other forum (not here) insisted that a 15000000 degree Celcius flame is flame, not plasma, but I think at that temperature air must already becoming plasma.

Last edited: Oct 14, 2012
2. Oct 14, 2012

### PhysicoRaj

3. Oct 14, 2012

### DrZoidberg

The higher the temperature of air is the more ions it will contain. Even at room temperature there are a few ions that are mostly generated by radiation.
A candle flame contains a lot more ions. Put a burning candle into a microwave oven and you get a nice plasma ball because the flame is so conductive it absorbs most of the microwaves. What percentage of air molecules must be ionized to call it a plasma is not clearly defined. So you can't give an exact temperature at which air turns into plasma. The hotter it is the more it is ionized.

4. Oct 15, 2012

### PhysicoRaj

But without the influence of any radiation, or electric fields, etc., using only heat as the source, still can it have a vague ionization temperature????

5. Oct 15, 2012

### Drakkith

Staff Emeritus
6. Oct 16, 2012

### Enthalpy

At 3000K oxygen dissociates significantly into neutral individual atoms. Nitrogen needs several 1000K more. Significant ionization takes a hotter temperature. But very slight ionization happens before.

You can look for the ionization energy and divide it by R (if moles, or by k if molecules) to get a temperature where oxygen is half-way ionized.