Design and construction of the Texas Tech tokamak

Abstract

A small, circular cross section research tokamak (R = 45.7 cm, a = 16.2 cm) has been designed and constructed at Texas Tech University. The basic facility includes a 130 kJ toroidal field (B) bank, 18 kJ ohmic heating bank, and a 2 kJ vertical field bank. A 40 kW, 35 kHz discharge cleaning oscillator produces a low energy plasma ('3 1 - 2 pps to prepare the chamber walls for tokamak discharges. After several hours of discharge cleaning, the tokamak typically produces discharges of 10 - 12 ms, with I = 20 kA, Bt = 0.95 T, and VL = 3.5 V at dI/dt = 0. Design and construction information for the basic device is presented together with plasma positioning coil development, loop voltage (V.) interpretation, and current probe design. Presently efforts are directed toward the completion of a 4 mm microwave density diagnostic system and measurement of Doppler broadened impurity 1ines for determining the ion temperature.