Dust acoustic solitary waves and double layers in a dusty plasma with an arbitrary streaming ion beam

The effects of variable dust charge, dust temperature and an arbitrary streaming ion beam on small amplitude dust acoustic waves are investigated. It is found that both compressive and rarefactive solitons as well as double layers exist. There exists a critical ion beam velocity below which the ion beam is unable to generate solitons. Korteweg-de Vries (KdV) equations with third and fourth-order nonlinearity at the critical values are derived and the properties of dust acoustic solitary waves are discussed. In the vicinity of the critical values, KdV-type with mixed nonlinearity is obtained. The quite dense positive ion, the dust temperature, the ion beam density, mass ratio and temperature govern the existence of dust acoustic waves. The findings of this investigation may be useful in understanding laboratory plasma phenomena and astrophysical situations. (C) 2003 American Institute of Physics.