An explanation of the sheath instability

When the sheath accelerates in its plasma–bound motion as a result of the ion response to the electric field, one has a top-heavy equilibrium. In the sheath frame ions are accelerated towards the wall–sheath boundary. In such a situation sheath may become unstable. The sheath instability is examined as the Rayleigh–Taylor (RT) instability and RT growth rate is compared with the reported sheath instability in the literature.