Introduction to Plasma
\(\bullet\) We are surrounded by plasmas starting from the ionosphere a hundred kilometers above us, which is connected to the sun via the plasma of the solar wind.
\(\bullet\) The very tenuous interstellar space is a plasma and so are the largest objects that emit x-rays in the universe.
Plasma State
\(\bullet\) Plasma is a fundamental state of matter: by heating the mater changes from a solid \(\rightarrow\) liquid \(\rightarrow\) gas \(\rightarrow\) plasma.
\(\bullet\) When gas is heated above a certain temperature, or it is subject to strong electromagnetic fields, it gets ionized, and a transition towards the so-called fourth state of matter(coined by W.crookes in 1879), plasma state, is observed.
\(\bullet\) Compare
Ancient: Universe - Earth, water, air, fire
Modern: Universe - solid, liquid, gas, plasma
\(\bullet\) Plasma: Introduced by Tonks and Irving Langmuir(Nobel Prize winner) in 1928.
\(\bullet\) Plasma: Greek words - moldable substacne; jelly.
\(\bullet\) Plasma ionized gas with \(n_e = n_i\); macroscopically charged neutral. Much more complicated than many single charged particle becuase of collective effects.
Definition of Plasma
\(\bullet\) The ensemble of freely moving charged particles of both signs, i.e., ionized gas, can be considered as plasma if the Debye length is small compared with dimensions of the volume occupied by the gas. (Langmuir)
\(\bullet\) A plasma is a quasi-neutral gas of charged and neutral particles which exhibits collective behavior (F.F. Chen)
\(\bullet\) A plasma is a gas of charged particles, in which the potential energy of a typical particle due to its nearest neighbor is much smaller than its kinetic energy. (D. R. Nicholson)
\(\bullet\) A plasma may be roughly defined as a system containing mobile charges, in which the electric and magnetic interactions between particles play a dominant role in the dynamics of the systems. (J. M. Dawson)
\(\bullet\) A plasma is collection of charged particles, usually of opposite sign, that tends to be electrically neutral. We often describe a plasma as the fourth state of matter. Adding energy to a solid melts it and it becomes a liquid; adding energy to a liquid boils it and ib becomes a gas; adding energy to a gas ionizes it and it becomes a plasma. (J. L. Shohet)
\(\bullet\)The plasma state is a characteriza
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