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Particle‐In‐Cell Simulations of the Ball‐Pen Probe
Author(s) -
Komm M.,
Adamek J.,
Pekarek Z.,
Panek R.
Publication year - 2010
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.201010137
Subject(s) - langmuir probe , particle in cell , tokamak , plasma , physics , phase space , atomic physics , plasma diagnostics , ion , computational physics , saturation (graph theory) , quantum mechanics , mathematics , combinatorics
Abstract In this paper, we present results of Particle‐In‐Cell simulations of a simplified model of the Ball‐pen probe (BPP). The BPP is a probe designed for direct measurements of plasma potential in the scrape‐off layer (SOL) of tokamaks. The probe is based on a standard Langmuir theory, which states that when the ratio of ion and electron saturation currents flowing to the probe collector approaches zero, the floating potential of the collector is close to the plasma potential. However, it is unclear whether the Langmuir theory is still valid in such a complex geometry, where the probe tunnel can work as a filter in velocity phase‐space and as such violates the Maxwellian distributions of particle velocities. To verify the validity of the theory a simplified model of BPP has been studied using the SPICE2 code (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)