Plasma Physics: Its Importance for the Advancement of Physics.

It is more than a century since the publication of the original paper by Langmuir on plasma oscillations.(1) The discovery of an electromagnetic wave in a fully conducting gas -- now called the Alfven wave -- was a surprise in 1942.(2) Studies directed toward controlled thermonuclear fusion have advanced dramatically the understanding of plasma behavior. Equilibrium and stability of a plasma in a magnetic field, weak turbulence theory based on the quasi-particle picture of plasma waves with interacting particles, and plasma kinetic theory to describe particle behavior in phase space are among the major achievements during the era of fusion research. Astrophysics and space physics have also contributed significantly to the understanding of the plasma behavior in large scale. Research in plasma physics has also resulted in discoveries of fundamental physics phenomena which have produced significant impacts toward advancements in other branches of physics.