  Experimental results on an auto-oscillatory pattern observed in a complex
plasma are presented. The experiments are performed with an argon plasma which
is produced under microgravity conditions using a capacitively-coupled rf
discharge at low power and gas pressure. The observed intense wave activity in
the complex plasma cloud correlates well with the low-frequency modulation of
the discharge voltage and current and is initiated by periodic void
contractions. Particle migrations forced by the waves are of long-range
repulsive and attractive character.
