Gravitational Instability Analysis in Multi-Ion Dense Quantum Magnetoplasma

Electrostatic Gravitational or Rayleigh-Taylor (RT) instability in an inhomogeneous magnetized multi-ions plasma with some fraction of quantum mechanical electrons. The effect of Bohm potential, temperature degeneracy and magnetic field are carried out. A generalized dispersion relation is deduced under the drift approximation. The presence of negative ions with their different streaming velocities make the dispersion relation a cubic equation. Different roots of both real and imaginary parts of the RT mode are studied by using the Cardano method of solving the cubic equation. The growth rates of RT instability are examined analytically and numerically. It is shown that the basic features of these waves are significantly modified by the positive and negative ions drift speed as well as by the magnetic field and density. Relevance of the work regarding to dense astrophysical plasmas is pointed out.