Description
Compact torus (CT) injection is a promising technique for active control of plasma density profiles in magnetic confinement fusion devices. To explore CT trajectories and fuel deposition features, we designed a progressive experimental scheme using a high speed compact torus injector (KTX-CTI) with an integrated diagnostic system on the Keda Torus eXperiment (KTX) reversed field pinch device. The magnetic configuration was systematically varied to examine CT electromagnetic behavior under three operating conditions.
Experimental results demonstrate that CT injection drives eddy currents in the conducting shell and vacuum vessel, leading to strong, measurable electromagnetic coupling between the CT and surrounding conducting structures. A mirror image current loop model was developed to interpret the observed phenomena, showing excellent agreement with experimental data. During penetration into the bulk magnetized plasma, the CT expands continuously in physical size and magnetic topology. A toroidal magnetic field significantly accelerates CT magnetic structure breakdown; their electromagnetic interactions induce highly localized fuel particle deposition associated with rapid magnetic flux variations, which these effects enable precise core fueling and remarkable modification of the plasma density profiles.
These findings demonstrate that CT injection constitutes an effective, controllable localized fueling technique for magnetic confinement fusion devices, while the proposed model establishes a robust framework for analyzing CT-based fueling electromagnetic dynamics.
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