  Radio frequency waves do not penetrate into a plasma and are damped within
it. The electric field of the wave and plasma current are concentrated near the
plasma boundary in a skin layer. Electrons can transport the plasma current
away from the skin layer due to their thermal motion. As a result, the width of
the skin layer increases when electron temperature effects are taken into
account. This phenomenon is called anomalous skin effect. The anomalous
penetration of the rf electric field occurs not only for transversely
propagating to the plasma boundary wave (inductively coupled plasmas) but also
for the wave propagating along the plasma boundary (capacitively coupled
plasmas). Such anomalous penetration of the rf field modifies the structure of
the capacitive sheath. Recent advances in the nonlinear, nonlocal theory of the
capacitive sheath are reported. It is shown that separating the electric field
profile into exponential and non-exponential parts yields an efficient
qualitative and quantitative description of the anomalous skin effect in both
inductively and capacitively coupled plasma.
