Bohm sheath criterion and dust charging for active magnetized plasma in the presence of q-nonextensive electron distribution

Abstract

We have investigated the Bohm sheath criterion and evolution of dust charge at the sheath edge for the collisional active magnetized plasma in the presence of q-nonextensive electron distribution. The set of governing equations has been numerically solved for given initial conditions, whereas the dust charging equation has been solved using the –Raphson method. The Bohm sheath condition for active plasma has been extended using the Sagdeev potential approach, and it has been found that gas pressure, obliqueness of the magnetic field, source and sink terms, and choice of electron distribution affect the Bohm velocity, sheath thickness, floating potential, and evolution of dust charge. As the magnetic field, gas pressure, and nonextensive parameter q increase, the Bohm velocity is found to be decreasing (from supersonic to subsonic), and its explicit effect can be seen on the dust charging process. The magnitude of the E × B drift velocity of ions at the sheath edge determines the Bohm velocity, floating potential, and dust screening length as well. Furthermore, we have presented the comparison of the obtained results for two different cases: (i) unmagnetized and magnetized cases and (ii) active and quiescent plasmas.