Tunnel probes for measurements of the electron and ion temperature in fusion plasmas
- Association EURATOM-CEA sur la Fusion Controlee, Saint Paul Lez Durance (France)
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 T{sub e} measurements 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 T{sub e}. 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.
- OSTI ID:
- 20641308
- Journal Information:
- Review of Scientific Instruments, Vol. 75, Issue 10; Conference: 15. topical conference on high temperature plasma diagnostics, San Diego, CA (United States), 19-22 Apr 2004; Other Information: DOI: 10.1063/1.1787581; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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