Design and fabrication of new version of Langmuir double circuit for the IR-T1 tokamak

Summary form only given, as follows. The IR-T1 is an air core transformer type tokamak with no diverter and conducting shell on it. The major parameters are: R=45.00 cm, a=12.50 cm, I/sub p/=20-40 kA, /spl tau//sub B/=20-25 ms, B/sub t/=6.1-9.0 kG, V/sub loop/=2.6-8 V, n/sub e/=0.7-3.0/spl times/10/sup 13/ cm/sup 3/, T/sub e/=150-250 ev, Z/sub eff/<2. The relative measurement of electron temperature and density, was done by a set of asymmetric Langmuir double probes. These probes can be operated in a relatively small voltage region, provides sufficient information about the plasma edge parameters, and therefore there is no need for a direct measurement of the ion saturation current which is about a few milliamperes. The reduction of applied voltage should greatly simplifies the operation of the double probe and eliminates unwanted induced electric fields in small tokamak devices. For this reason we had to design a set of collectors so that the sheath surface area be large enough to consider it as a plasma. The probe power supply was designed and completed at the research institute.