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Name: Taylor R. K.
Status: student
Age: 15
Location: N/A
Country: N/A
Date: 2/25/2004


Question:
What is the process called going from a gas to the plasma state? vice-versa ?


Replies:
Taylor,

The entire process (referred to as a change in phase) -- from melting to a liquid, boiling to a gas, and passing into the plasma state -- is a matter of heat input and resultant energy content. Plasma is a highly excited state of matter wherein ordinary molecular structure is destroyed. In that condition, what's left is a super-hot fluid of ions (charged atoms) and electrons. Materials in the electric arc of a welder's torch are in the plasma state.

Regards,
ProfHoff 814


gas to plasma: ionization, (alternate terms: ignition or (electrical) breakdown, excitation )

plasma to gas: recombination (alternate terms: extinction, extinguishing, quenching and maybe depletion, de-excitation.)

Plasmas we make are usually only partially-ionized gasses. Most of the atoms are still neutral gas molecules, and only a minority are ions. The average brightly glowing neon sign will be less than 1/1000th ionized. Mostly it is gas with a few "upsets" in it. Deep inside the sun, above 20,000 degrees C, one could find nearly total ionized plasma. In the hot vacuum near the sun too.

In the alternate terms you will notice that plasma is verbally analogous to fire. The broken-up atoms in a plasma have a decisively high energy level, as do the broken-up molecules in a combustion reaction. Ionization is present or absent, and combustion is either present or absent.

English is a little short of good specific terms on this topic. So define your own terms, and that will help refine your thoughts.

Jim Swenson



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