Khrapak, S. A., Thoma, M. H., Chaudhuri, M., Morfill, G. E., Zobnin, A. V., Usachev, A. D., et al. (2013). Particle flows in a dc discharge in laboratory and microgravity conditions. Physical Review E, 87(6): 063109, pp. 1-8. doi:10.1103/PhysRevE.87.063109.