Abstract
Effects of electron-and ion-viscosity on plasma instabilities are investigated in the plasma system including ionneutral and electron-neutral collisions. In the waves propagating parallel to magnetic field, the low frequency mode become unstable with the existance of the viscosity of the drift, electrons. The critical velocity for the instability and the unstable region for large wave number are shown with the parameter of Te/Ti. The waves in a high frequency region is also shown to be excited with the existance of the ion viscosity. Further, the low frequency wave which propagates perpendicular to a weak magnetic field is shown to be excited with the existance of the viscosity of the drift eledtrons.
