http://www.researchonline.mq.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:5804 A comment on 'Effect of ionization on ion acoustic solitary waves in a collisional dusty plasma' by Samiran Ghosh, Journal of Plasma Physics, Volume 71, Issue 04, August 2005, pp 519-526. 2010-01-27T22:26:12.438Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:5820 In the present work the structure of the magnetized sheath is investigated in the multifluid framework. The ambient magnetic field is assumed parallel to the wall and the effect of the plasma magnetization, plasma ionization, and plasma-neutral collisions on the sheath is examined. It is shown that the width of the non-neutral boundary layer is dependent on the collision frequencies as well as on the plasma magnetization. The size of the sheath layer can decrease with the increase in magnetic field. The increase in the ion-neutral collision can also adversely affect the sheath size. The equilibrium and levitation of the dust particles in a collisional magnetized sheath are shown to depend on the collision frequencies and on the magnetization. Further, the increase in the collision or magnetization invariably leads to the presence of the positively charged grains near the plasma wall suggesting that the grain levitation inside the charged layer is implicitly dependent on the plasma parameters in a nontrivial way. 2010-01-27T22:25:58.059Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:5822 The present work investigates the parametric instability of parallel propagating circularly polarized Alfvén (pump) waves in a collisional dusty plasma. It is demonstrated that the relative drift between the charged dust and the electrons and ions gives rise to the Hall effect resulting in the modified pump wave characteristics. Although the linearized fluid equations with periodic coefficients are difficult to solve analytically, it is shown that a linear transformation can remove the periodic dependence. The resulting linearized equations with constant coefficients are used to derive an algebraic dispersion relation. The growth rate of the parametric instability is a sensitive function of the amplitude of the pump wave as well as to the ratio of the pump and the dust-cyclotron frequencies. The instability is insensitive to the plasma-beta parameter. The possible application of the result in the astrophysical context is discussed. 2010-01-27T22:25:55.881Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:5823 The presence of the immobile charged dust in the plasma modifies the scale over which the Hall effect becomes important. For a positively charged dusty background this scale can become arbitrarily large. It is shown that the emergence of the Hall effect in an immobile charged background is related to the presence of an electric field that operates over the plasma gyration period. The generalized flux, which is a combination of the magnetic and fluid vortex flux, can decay due to the presence of the charge or the density inhomogeneities. The normal mode behavior of such a dusty plasma could be very different for positively and negatively charged grains. Whereas for negatively charged grains the usual magnetohydrodynamic (MHD) modes are present in the system, for positively charged grains, the Alfvén mode may not exist if Znd~ne, where Z is the charge of the dust and nd(ne) are the dust (electron) number densities. In the presence of the inhomogeneities, inertialess dusty plasma is subject to the Hall instability. It is shown that the growth rate of the Hall instability is proportional to the whistler frequency. Since Hall drift is nondissipative in nature, this instability can play important role in redistributing the magnetic energy from the large to small scales. 2010-01-27T22:25:54.609Z ]]>