Colloquium

  • 3-D magnetic field physics in fusion plasmas

  • Speaker : 인용균 / In Yongkyoon
    Affiliation : UNIST
    Date : August 29, 2018 4:00 PM
    Place : Building 110 Room N103
    Contact : inyongkyoon@unist.ac.kr
  • Abstract

  • Magnetically confined plasmas are fundamentally subject to 3-D magnetic field (dB), though the assumption of axisymmetric (2-D) field (B0) proved amazingly powerful in magnetohydrodynamics over the years. The presence of 3-D magnetic fields is often regarded as ‘undesirable’ in terms of fusion plasma stability and transport. But it has been also recognized as one of the ‘essential’ tools to control edge-localized-modes (ELMs), whose particle and energy outbursts may endanger the integrity of the divertor and plasma facing components in toroidal devices. The externally applied 3-D magnetic field, called resonant magnetic perturbation (RMP), is designed to drive 3-D magnetic fields stochastically, enhancing the edge transport to keep ELMs from reaching destabilizing conditions. In recent years, the Korea Superconducting Tokamak Advanced Research (KSTAR) in Daejeon, Korea became one of the leading devices in the world in addressing such 3-D magnetic field physics in fusion plasmas. In fact, the KSTAR provides an ideal environment for the 3-D magnetic field physics study, in that its erroneous background 3-D magnetic field (called ‘error field’of dB/B0 ~ 10-5) is lower by an order of magnitude than elsewhere. This helped the KSTAR uniquely explore and suppress the ELMs using the longest-wavelength 3-D magnetic field (dB/B0 ~ 10-3 – 10-4) that is notoriously fatal to many other tokamaks. The on-going forefront progress and future prospect in 3-D magnetic field physics, mostly based on the KSTAR research works, will be presented and discussed for ITER (under construction in Southern France for completion in 2025) and beyond.