  The theory of plasma physics offers a number of nontrivial examples of
partial differential equations, which can be successfully treated with symmetry
methods. We propose three different examples which may illustrate the
reciprocal advantage of this "interaction" between plasma physics and symmetry
techniques. The examples include, in particular, the complete symmetry analysis
of system of two PDE's, with the determination of some conditional and partial
symmetries, the construction of group-invariant solutions, and the symmetry
classification of a nonlinear PDE.
