  We show that longwavelength excitations of the quark-gluon plasma are
described by simple kinetic equations which represent the exact equations of
motion at leading order in $g$. Properties of the so-called ``hard thermal
loops'', i.e. the dominant contributions to amplitudes with soft external
lines, find in this approach a natural explanation. In particular, their
generating functional appears here as the effective action describing long
wavelength excitations of the plasma.

High Energy Physics - Phenomenology