5 research outputs found
Revisiting the anomalous rf field penetration into a warm plasma
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.Comment: 44 pages, invited paper at "Nonlocal, Collisionless Phenomena in
Plasma" worksho
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Landau Damping and Anomalous Skin Effect in Low-pressure Gas Discharges: Self-consistent Treatment of Collisionless Heating
In low-pressure discharges, where the electron mean free path is larger or comparable with the discharge length, the electron dynamics is essentially nonlocal. Moreover, the electron energy distribution function (EEDF) deviates considerably from a Maxwellian. Therefore, an accurate kinetic description of the low-pressure discharges requires knowledge of the nonlocal conductivity operator and calculation of the non-Maxwellian EEDF. The previous treatments made use of simplifying assumptions: a uniform density profile and a Maxwellian EEDF. In the present study a self-consistent system of equations for the kinetic description of nonlocal, nonuniform, nearly collisionless plasmas of low-pressure discharges is reported. It consists of the nonlocal conductivity operator and the averaged kinetic equation for calculation of the non-Maxwellian EEDF. This system was applied to the calculation of collisionless heating in capacitively and inductively coupled plasmas. In particular, the importance of accounting for the nonuniform plasma density profile for computing the current density profile and the EEDF is demonstrated. The enhancement of collisionless heating due to the bounce resonance between the electron motion in the potential well and the external radio-frequency electric field is investigated. It is shown that a nonlinear and self-consistent treatment is necessary for the correct description of collisionless heating
Landau damping and anomalous skin effect in low-pressure gas discharges: Self-consistent treatment of collisionless heating
In low-pressure discharges, where the electron mean free path is larger or comparable with the discharge length, the electron dynamics is essentially nonlocal. Moreover, the electron energy distribution function (EEDF) deviates considerably from a Maxwellian. Therefore, an accurate kinetic description of the low-pressure discharges requires knowledge of the nonlocal conductivity operator and calculation of the non-Maxwellian EEDF. The previous treatments made use of simplifying assumptions: a uniform density profile and a Maxwellian EEDF. In the present study a self-consistent system of equations for the kinetic description of nonlocal, nonuniform, nearly collisionless plasmas of low-pressure discharges is reported. It consists of the nonlocal conductivity operator and the averaged kinetic equation for calculation of the non-Maxwellian EEDF. This system was applied to the calculation of collisionless heating in capacitively and inductively coupled plasmas. In particular, the importance of accounting for the nonuniform plasma density profile for computing the current density profile and the EEDF is demonstrated. The enhancement of collisionless heating due to the bounce resonance between the electron motion in the potential well and the external radio-frequency electric field is investigated. It is shown that a nonlinear and self-consistent treatment is necessary for the correct description of collisionless heating