Tunnel probes for measurements of the electron and Ion temperature in fusion plasmas

J.P. Gunn, R. Schrittwieser, P. Balan, C. Ioniţǎ, J. Stöckel, J. Adámek, I. Ďuran, M. Hron, R. Pánek, O. Bařina, R. Hrach, M. Vicher, G. Van Oost, T. Van Rompuy, E. Martines

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We have developed tunnel probes for localized measurements of the electron and ion temperature in the edge plasma region of smaller tokamaks and stellarators. A normal tunnel probe for Temeasurements consists of a metallic tunnel of 5 mm diameter and 5 mm length, with the axis parallel to the magnetic field. One side is open, the other side is closed by a metallic backplate, isolated from the tunnel. If both electrodes are biased negatively, ions flow into the office, and their current is distributed between the tunnel and the backplate. The ratio of the two ion currents is a function of Te. With an additional diaphragm in front of the orifice, the probe becomes ion sensitive, since the electrons are prevented from the tunnel because of their smaller gyroradius, but ions can still reach it. In this way, the perpendicular ion temperature can be derived. By segmenting the tunnel axially into two parts, also an approximate measure for the parallel ion temperature can be found. © 2004 American Institute of Physics.
Original languageEnglish
Pages (from-to)4328 - 4330
Number of pages3
JournalReview of Scientific Instruments
Issue number10 II
Publication statusPublished - Oct 2004
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Instrumentation

Cite this

Gunn, J. P., Schrittwieser, R., Balan, P., Ioniţǎ, C., Stöckel, J., Adámek, J., ... Martines, E. (2004). Tunnel probes for measurements of the electron and Ion temperature in fusion plasmas. Review of Scientific Instruments, 75(10 II), 4328 - 4330. https://doi.org/10.1063/1.1787581