| Reversed field pinch (RFP) is an alternative magnetic confinement configuration with low magnetic field. The toroidal field and poloidal field of RFP generated by toroidal plasma current are comparable, which significantly reduces the stresses of magnets. Lower external magnetic field also leads high plasma β for the benefit of magnetic fusion. On the other hand, because the equivalent plasma resistance is relatively large, fusion ignition could be realized only by ohmic heating while plasma current is large enough. The physical rational for the engineering specifications for a new RFP device KTX(Keda Keda Torus eXperiment) has been worked out based on the investigation of the research condition of RFP. The conceptual of KTX has been completed for each system. To better under stand the startup phase for future RFP operation of KTX, the physical process of RFP has been experimental studied during current ramping phase on MST.The physics goals of KTX has been summarized:RWM control, boundary conditioning for confinement imporvement, current density profile control for confienment improvement, and single helical state research. Based on the design parameters of KTX, the confinement of KTX is predicted. The discharge waveforms are simulated by combining the1dimension equilibrium model and energy flux conservation.The desing principle for each system of KTX are discussed. Those system include ohmic field and equilibrium field system, toroidal field system, vacuum vessel and conducting shell. Toroidal field coils are designed using finite element model. A distribution of equilibrium coils is designed by two dimensional equilibrium calculation. The effect of current density profile and pressure profile is studied. Bayesian physics design has been applied to the desing of beam positions of multi-chord interferometer, which provide a reference for the arrangement of diagnostic windows on KTX.Parameters of magnetic and kinetic profiles of plasma during the ramping up phase of plasma current has been measured and compared with different starting up initial toroidal magentic field. The measurement takes advantage of MST’s diagnostic set in noninvasive plasmas with peak value around600kA. For higher starting up toroidal magnetic field plasmas, the poloidal flux consupmtion is lower and abnormal ion heating is found during current ramping phase. The evolution of q profile is consistent with the activity of m=1modes. The inductive flux consumption and resistive flux consumption are calculted to analysis the decreased poloidal flux for high start up toroidal field. |
