2) Where can we find plasmas?
Plasmas can be found in the situations where the temperature or
the electric field is high enough to ionize the gas. The examples can be
divided into three main categories: space, terrestrial and artificial
Ø Space: Sun and other stars, solar wind, interstellar medium,
etc.
The
surface of the sun
Ø Terrestrial: Ionosphere, lightning, etc
Lightning
Ø Artificial: Fluorescent lamp, electric arcs, fusion
devices, etc.
Inside a fusion reactor
From the above
examples one can see the variety of situations, where one encounters plasmas,
as well as the differences between them. For example, the sizes can vary from
arcs created in a lab, to vast regions of space. Other characteristics also
vary by several orders of magnitude, such as the density, the magnetic field
that is present, or the relaxation time available to the system.
If we add the
fact that most matter in the universe is in the form of a plasma, one can
easily see the importance of this area of research.