An experimental investigation of the propagation of a compact toroid along curved drift tubes

Abstract

Compact toroid (CT) injection is a viable technology for fuelling large tokamak reactors in the future. Experimental demonstration of CT injection has thus far been conducted using horizontal injection in the midplane of tokamak devices. However, recent analyses indicate adverse effects of the toroidal magnetic field on CT injection. In order to avoid these adverse effects, the CT would need to be injectable in any direction. We have therefore devised a curved drift tube to change the direction of CT propagation and have experimentally demonstrated its efficacy. It has been observed that a CT can be transported smoothly through curved drift tubes with 45˚and 90˚bends without any appreciable change in the CT parameters. The magnetic field, electron density and speed of CTs transported through both 45˚and 90˚bends are similar to those observed in a linear drift tube.

First Results of Magnetized Plasma Flow Injection on the TPE-RX Reversed-Field Pinch

“…The particle content increased by ∆ N RFP (= ∆ n g × V p ) ~ 2.8 × 10 19 and the particle inventory of the plasma flow was N inj ~ 3.8 × 10 19 . Therefore, the fueling efficiency ε = ∆ N RFP /N inj was roughly 74% [4]. This increase rate was approximately twice as fast as that in the case of singleoperation gas-puffing on MCPG (dashed line).…”

Demonstration of Tokamak Ohmic Flux Saving by Transient Coaxial Helicity Injection on NSTX

“…Coaxial Helicity Injection (CHI) has previously been used for spheromak formation [3][4][5], in reconnection merging experiments [6] and in spherical torus plasma formation [7]. Initial transient CHI work on NSTX demonstrated the generation of a closed-flux equilibrium using the transient CHI process [8].…”

Start-up assist by magnetized plasma flow injection in TPE-RX reversed-field pinch

“…The polarity of the magnetic helicity can be reversed by changing the direction of the bias field. Total helicity K inj generated by the gun helicity source can be estimated by K inj = 2 V g ψ b dt [7]. Here, V g is the gun voltage and ψ b is the bias flux.…”