Current penetration in the PLT tokamak

Current penetration in the PLT tokamak is modeled by a one dimensional magnetic field diffusion code assuming neoclassical resistivity. The code uses the measured temperature and density profiles as well as current and voltage measurements to evaluate Z/sub eff/. Under certain conditions, the resulting calculations of Z/sub eff/ during the startup phase have been considerably larger than the Z/sub eff/ determined spectroscopically indicating the presence of an enhanced current penetration mechanism. Furthermore, these calculations indicate that the gross energy confinement time is substantially less during the startup phase than in the quasi-steady state.