  A new type of nonlinear dust pulse structures has been observed in afterglow
complex plasma under microgravity condition on board the International Space
Station (ISS). The dust pulses are triggered spontaneously as the plasma is
switched off and the particles start to flow through each other
(uni-directional or counter-streaming) in the presence of a low-frequency
external electric excitation. The pulses are oblique with respect to the
microparticle cloud and appear to be symmetric with respect to the central
axis. A possible explanation of this observation with the spontaneous
development of a double layer in the afterglow of complex plasma is described.
