Obliquely propagating solitary kinetic Alfven wave in a collisional dusty plasma

An obliquely propagating solitary kinetic Alfven wave in a low beta dusty plasma (beta << m(e)/m(i)) is studied by considering the ion motion along the magnetic field and the collisional effect of electrons. The existence condition for a solitary wave for a collisionless dusty plasma is re-examined. It is found that there is an upper limit of the possible Alfvenic Mach velocity, imposed by dust particles. The Mach number lies between l(z) and l(z)/root N-d, where l(z) is the directional cosine and N-d is the dust particle charge density. In the collisional case, the same upper limit of the Mach velocity is found, and the solitary wave turns into an oscillating double layer. The damping scale and the size of the oscillation structure increase with increasing dust particle charge density. The damping scale and the size of the oscillation structure are estimated by using the virial theorem. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3425867]