• B P Pandey

      Articles written in Pramana – Journal of Physics

    • Streaming instability of a dusty plasma in the presence of mass and charge variation

      B P Pandey C B Dwivedi

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      We study the effect of the mass and charge dynamics on the collective behaviour of a dusty plasma. It is shown that the finite non-zero streaming velocity of the dust grains leads to a novel coupling of the dust mass fluctuation with other dynamic variables of the plasma and the grains. The mass fluctuations causes a collisionless dissipation and provides an alternate channel for the beam mode instability to occur. Physically the negative energy wave associated with the beam mode couples to the mass fluctuation induced dissipative medium to produce the instability. We conclude that the higher value of the ion mass density to the dust mass density ratio reduces the threshold value for the onset of the instability. Its application in the astrophysical context is discussed.

    • Kinetic description of ion acoustic waves in a dusty plasma

      B P Pandey Susheel Kumar

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      A self-consistent model for the description of the ion sound wave in a dusty plasma is given. We show that proper consideration of the ion attachment to the grains gives rise to the dissipation of the ion acoustic wave in a dusty plasma medium. Dissipation rate is proportional to the sum of the electron and twice the ion attachment frequencies.

    • Jeans-Buneman instability in a dusty plasma

      B P Pandey G S Lakhina

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      A self consistent formulation of the Jeans instability of a dusty plasma with proper inclusion of charge dynamics is described. It is shown that charge fluctuations significantly affect the Jeans as well as the Buneman mode. For plasma particles (electrons and ions) in local thermal equilibrium, the Jeans lengthλJ is given byλJλgF(R, ε, β/η), whereλg is the Debye length of the charged grains,R is the square of the ratio of the Jeans to the plasma frequency of the grains,ε is the square of the ratio of the Debye length of the grains and the plasma particles andβ/η is the ratio of the attachment to the decay frequency of the electronic charges to the grain surface. The functional form ofF is given in the text. Numerical investigation of the Jeans-Buneman mode for a two and three component plasma shows that the Jeans mode dominates atD≪1 (wherek is the wave number andλD is the Debye length of plasma particles), whereas atD≫1 only the Buneman mode operates. Charge fluctuations reduce the area of overlap of the two modes. Furthermore, in the absence of gravity, there exists a new, charge fluctuation induced unstable mode in a streaming dusty plasma. Astrophysical applications of the results are discussed.

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