Often referred to as the fourth state of matter (solid, liquid, gas, plasma).
In a solid state all the molecules, atoms, and Ions have a defined place in a lattice structure.
In a liquid the lattice structure is dissolved. The material is a fluid and takes the form of its container.
In a gas the particles move freely and randomly within the container.
In plasma, electrons have been knocked out of the outermost energy orbits (Ionization), leaving unpaired electrons, highly reactive radicals are now available to react with the products surface.
Each stage requires the addition of energy for its transition to the more energetic state.
Plasma that is generated is a chamber with reduced pressure typically in the range of 10 -2 to 10-4 atmospheres.
The rate at which process gas is bleed into the chamber is matched to the capacity of the vacuum pump to maintain the desired pressure.
Reacted process gas is evacuated from the chamber ensuring a consistent and repeatable process unaffected by the surrounding environment.
The environment in the production area remains unaffected by the process, for example no Ozone as can be the case with atmospheric plasma.
Yes, if enough energy is applied.
Atmospheric plasma systems are used but require far more energy and process gas.
They can produce high temperatures for cutting metal for example.
In nature examples of atmospheric pressure plasma are present.
Lightening is caused by a high static charge building up between air and water or ice crystals. When the potential is high enough to Ionize the air a so-called plasma channel is formed (the lightening flash), this can reach temperatures as high as 30,000 °C.
Fire. A flame is a weak form of plasma. It is sometime used for etching some polymers before printing.
The northern lights are caused by the interaction of solar winds with earth’s magnetic field and atmosphere. The color is dependent on the gas with which they react, green and red from Oxygen and blue or purple from nitrogen.
These same colors can be seen inside a plasma chamber dependent on the process gas.
No
The chamber is at reduced pressure, so any flow is into the chamber in case of a leak.
In case of a leak the plasma would be extinguished as the energy levels are too low to support plasma at pressures above the operating pressure of the chamber.
None from within the plasma treater.
Even Hydrogen and oxygen mixtures present no danger when used in the process, as the pressure in the chamber is so low.
Obviously, the standard precautions must be taken for storage etc.
No
Special glass is used for any viewing windows to prevent this.