Magnetorotational instability in spin quantum plasmas

The magnetorotational instability (MRI) is analyzed using a two fluid model with the effect of spin magnetization in a differentially rotating degenerate electron-ion (e-i) quantum plasma. The electrons are taken to be degenerate, whereas ions are considered as classical owing to their large inertia. The general dispersion relation for spin quantum e-i plasma is derived and a local dispersion relation for MRI is obtained by applying MHD approximations. The obtained MRI criteria is discussed for both magnetized and unmagnetized plasma duly modified by spin correction terms. The instability criteria differ significantly from that reported for the case of classical plasma. Spin magnetization plays a vital role via coupling to the Alfvénic speed and can alter the instability criteria which leads to the transport phenomenon in compact astrophysical objects.