Characteristics of global confinement properties in TPE-series reversed-field pinch devices

Abstract

A confinement database of the reversed-field pinch (RFP) devices of the toroidal pinch experiment (TPE) series has been established. The TPE database contains global confinement properties under various experimental conditions for four different devices and seven different cases, which cover two decades of experiments. Characteristics of the TPE database have been extracted under consistent experimental conditions of conventional RFP discharges, and scaling laws of the poloidal beta, βp and energy confinement time, τ E, are given against independent parameters that include the size of the plasma and the pinch parameter Θ. Scaling laws of and are obtained for a set of scans, where a is the plasma minor radius, Ip the plasma current and N the column density. The scaling of τ E on a, Ip, and I/N is similar to that dominated by the transport under tearing instability. Another scaling shows that τ E is inversely proportional to the Joule input power. The scaling for the apparent effective charge shows a positive correlation both with Ip and I/N.