Kinetic Investigation of the Planar Multipole Resonance Probe

Active Plasma Resonance Spectroscopy (APRS) is a well-established plasma diagnostic method: A radio frequency signal is coupled into the plasma via a probe or antenna, excites it to oscillate, and the response is evaluated via a mathematical model. Many APRS probes are invasive and perturb the plasma by their physical presence. The planar Multipole Resonance Probe (pMRP) [1] solves this problem: It can be integrated into the chamber wall and minimizes the perturbations. Previous work has studied the pMRP in the frame of the cold plasma model (Drude model) [2], missing important effects like collision-less damping. In this work, a kinetic model is developed to investigate the behavior of the pMRP more closely. This model consists of the collision-less Vlasov equation, which is coupled with the Poisson equation under the electrostatic approximation. The spectral response of the probe-plasma system is found by calculating the complex admittance. This model covers kinetic effects and overcomes the limitations of the cold plasma model. [1] C. Schulz, T. Styrnoll, P. Awakowicz, I. Rolfes, IEEE Trans. Instrum. Meas. 64, 857 (2015). [2] M. Friedrichs and J. Oberrath, J. EPJ Techn. Instrum. 5, 7 (2018).