Here is an example of a plasma originally used to observe
the H3+ molecular ion.
An uncooled plasma tube.
A liquid-nitrogen-cooled plasma most efficiently used
for carbocation spectroscopy named "E.T." The
gas enters into the discharge region through 8 pairs
of inlets that are constricted at the point of entry.
Inlets of a pair face each other accross the plasma
region so that jetlike streams from them meet at the
center and cause fresh chemical reactions in the optical
Here is the schematic of a general discharge tube
without any cooling jacket. Different shells surround
this based on the source of cooling: air, water, or
"The Black Widow." Here is an example of an empty
discharge tube that we are presently using.