On the two-stream instability with electron spin effects

We study electrostatic two-stream instability using a separated spin quantum hydrodynamic model in magnetized degenerate collisionless electron-ion plasma. We report that the separate spin evolution gives rise to some new real modes together with unstable modes for a specific range of wavenumbers. We notice that incorporating spin-polarization effects of plasma species, the two-stream instability significantly changes. On increasing the spin-polarization, the growth rate decreases. On the other hand, increasing streaming to the Fermi velocity ratio enhances the growth rate. Thus, the two effects, spin polarization and streaming, counter balance each other.