Measurement of edge plasma parameters in IR-T1 Tokamak by double Langmuir probe

Summary form only given. The IR-T1 Tokamak is an air-core transformer type Tokamak, there is no conductive shell on it. The vacuum chamber was made of 4 mm thick stainless steel with minor and major radii of 12.5 cm and 45 cm respectively. Measurements of T/sub e/ have been observed in the IR-T1 and the circuits of the double probe were designed and fabricated by the author. This probe can be moveable in the horizontal direction, therefore we can measure the temperature along a 1 cm distance. It shows that negative and positive polarity are exactly symmetric for the electron temperature measured in the flat top plasma. Sweeping line and amplitude of the ramp is adjustable from double probe results and it is possible to calculate impurity fluxes from the wall components especially for the cases where there is an appreciable edge density present. Then the impurity fluxes greatly over estimate this effect which appears to be due to the suppression of the electron current to the probe in the presence of a strong magnetic field.