Parameter Tree:
EARTH SCIENCE > SUN-EARTH INTERACTIONS > IONOSPHERE/MAGNETOSPHERE DYNAMICS > PLASMA WAVES

Definition:
A plasma is a gas containing ions, electrons, and a magnetic field, and
therefore capable of
conducting electric currents. A plasma wave is a set of particles under the
influence of electromagnetic fields, exhibiting wave-like motions with
amplitude and periodicity.


Reference:
http://www-istp.gsfc.nasa.gov/Education/gloss.html