A self consistent formaluation of the Jeans instability of a dusty plasma with proper inclusion of charge dynamics is described. It is shown that charge fluctuatons significantly affect the Jeans as well as the Buneman mode. For plasma particles (electrons and ions) in local thermal equilibrium, the Jeans length λj is given by λj ≈ λgF(R,∈,β/η), where λg 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, ∈ is the square of the ratio the Debye length of the grains and the plasma particles and β/η is the ratio of the attachment to the decay frequency of the electronic charges to the grain surface. The functional from of F 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 at kλD ≪ 1 (where k is the wave number and λD is the Debye length of plasma particles), whereas at kλD ≫ 1 only the Bunesman mode operates. Charge fluctuations reduce the area of overlap of the two modes. Furthermore, in the absence of gravity, there exists a neew, charge fluctuation induced unstable mode in a streaming dusty plasma, Astrophysical applications of the results are discussed.
|Number of pages||14|
|Journal||Pramana - Journal of Physics|
|Publication status||Published - Feb 1998|
- Charge fluctuations
- Jeans length
- Jeans-Buneman instability