QUANTUM SUPPRESSION OF ION ACOUSTIC INSTABILITY IN DENSE PLASMA

Abstract

A 1-D quantum hydrodynamics (QHD) model has been used to investigate the stability criteria of the ion-acoustic wave in a dense electron-ion quantum plasma. The ion-acoustic instability caused by electron streaming is well understood in classical plasma; however, when quantum effects are considered, the stability criteria undergo significant modifications. In the present work, electrons are described by the quantum fluid equation with $H = \frac{\hbar \omega_{pe}}{2k_{B}T_{Fe}}$ representing the quantum diffraction of the electron wavepacket. In classical plasma, even a small value of electron streaming velocity is enough to trigger ion acoustic instability; however, in presence of parameter $H$, a much higher value of electron streaming velocity is required to excite the instability. In this work, it is observed that the electron streaming contributes to the excitation of the instability, which gets suppressed due to the quantum effects of the electron, whereas the streaming ion provides energy to the wave mode.