Operating characteristics of a new ion source for KSTAR neutral beam injection system

Abstract

A new positive ion source for the Korea Superconducting Tokamak Advanced Research neutral beam injection (KSTAR NBI-1) system was designed, fabricated, and assembled in 2011. The characteristics of the arc discharge and beam extraction were investigated using hydrogen and helium gas to find the optimum operating parameters of the arc power, filament voltage, gas pressure, extracting voltage, accelerating voltage, and decelerating voltage at the neutral beam test stand at the Korea Atomic Energy Research Institute in 2012. Based on the optimum operating condition, the new ion source was then conditioned, and performance tests were primarily finished. The accelerator system with enlarged apertures can extract a maximum 65 A ion beam with a beam energy of 100 keV. The arc efficiency and optimum beam perveance, at which the beam divergence is at a minimum, are estimated to be 1.0 A/kW and 2.5 uP, respectively. The beam extraction tests show that the design goal of delivering a 2 MW deuterium neutral beam into the KSTAR Tokamak plasma is achievable.

Suppression of toroidal Alfvén eigenmodes by the electron cyclotron current drive in KSTAR plasmas

“…Principal source of fast ions in KSTAR is the deuterium NBI (referred to as NB1) [33], located at the L-port. As shown in figure 1, NB1 system consists of three on-axis tangential beamlines.…”

Role of fast-ion transport manipulating safety factor profile in KSTAR early diverting discharges

“…The first NBI (NB1) system [10] of KSTAR has three ion sources. In all three, the beam injection geometry is tangential, but each has a different radial tangency, as shown in figure 1.…”