Davorak said:
I just took undergrad plasma physics last semster and batery acids as well as electons in plasma where considered a plasma.
An ionized gas is certainly the most common definition on the web.
Plasma as defined by the Plasma Dictionary at
Lawrence Livermore National Laboratory:
http://plasmadictionary.llnl.gov/terms.lasso?-MaxRecords=1&-SkipRecords=4&-SortField=Term&-SortOrder=ascending&-Op=bw&ABC=P&page=detail
"Term: Plasma Definition: Known as the "Fourth State of Matter", a
plasma is a substance in which many of the atoms or molecules are
effectively ionized, allowing charges to flow freely. Since some 99% of
the known universe is in the plasma state and has been since the Big Bang,
plasmas might be considered the First State of Matter. Plasmas have
unique physics compared to solids, liquids, and gases; although plasmas
are often treated as extremely hot gases, this is often incorrect.
Examples of plasmas include the sun, fluorescent light bulbs and other
gas-discharge tubes, very hot flames, much of interplanetary,
interstellar, and intergalactice space, the Earth's ionosphere, parts of
the atmosphere around lightning discharges, laser-produced plasmas and
plasmas produced for magnetic confinement fusion. Types of plasmas
include - Astrophysical, Collisionless, Cylindrical, Electrostatically
Neutral, Inhomogeneous, Intergalactic, Interstellar, Magnetized,
Nonneutral, Nonthermal, Partially Ionized, Relativistic, Solid State,
Strongly Coupled, Thermal, Unmagnetized, Vlasov and more."
A good definition from Gettysburg college:
http://www.gettysburg.edu/academics/physics/Plasma/Plasma2.htm
Or courtesy of the University of Texas at Dallas William B. Hanson
Center for Space Sciences:
http://utd500.utdallas.edu/~kivanc/index_fut.html#Plasma
Another definition would be:
Plasmas are conductive assemblies of charged
particles, neutrals and fields that exhibit collective effects. Further, plasmas carry electrical currents and generate magnetic fields. Plasmas are the most common form of matter, comprising more than 99% of the visible universe.
But I like the definition:
electromagnetic (Maxwell-Boltzmann)** systems
http://www.plasmas.org/basics.htm
Also disscused before:
https://www.physicsforums.com/archive/topic/t-59693_How_is_cold_Plasma_possible?.html
Then you should have noted the definition from the classic text in
electrodynamics by Jackson:
"An ionized gas should be called a plasma when the length scale which
separates short range and long range behavior is short compared to the
length scale of interest. Not all ionized gases are plasmas. For example,
a very dilute gas of a few moving charged particles, interacting pairwise,
is not a plasma. The conduction electrons in a metal are not a plasma,
either. It is not always easy to tell if something is a plasma, really.
Crudely, if you have to consider the inertial effects of the positive and
negative charge carriers in the dynamics (say, in response to an applied
electric field), then you've got a plasma."
It's when you get electrons with long mean free paths - like when the
gas is very hot - or the gas is very rarefied that you get a plasma.
The ionic solutions don't qualify on either count - they are more like
the conduction electrons in a metal.
When you study more advanced physics and learn about things like the
Debye length [ what the Debye length is in a plama, which is different
than the Debeye length in an electrolyte ] - you will better understand
your error.
Dr. Gregory Greenman
Physicist