Asymptotic quasisymmetric high-beta three-dimensional magnetohydrodynamic equilibria near axisymmetry

Wrick Sengupta, Nikita Nikulsin, Rahul Gaur, Amitava Bhattacharjee

Research output: Contribution to journalArticlepeer-review

Abstract

Quasisymmetry (QS), a hidden symmetry of the magnetic field strength, is known to support nested flux surfaces and provide superior particle confinement in stellarators. In this work, we study the ideal magnetohydrodynamic (MHD) equilibrium and stability of high-beta plasma in a large-aspect-ratio stellarator. In particular, we show that the lowest-order description of a near-axisymmetric equilibrium vastly simplifies the problem of three-dimensional quasisymmetric MHD equilibria, which can be reduced to a standard elliptic Grad–Shafranov equation for the flux function. We show that any large-aspect-ratio tokamak, deformed periodically in the vertical direction, is a stellarator with approximate volumetric QS. We discuss exact analytical solutions and numerical benchmarks. Finally, we discuss the ideal ballooning and interchange stability of some of our equilibrium configurations.

Original languageEnglish (US)
Article number905900209
JournalJournal of Plasma Physics
Volume90
Issue number2
DOIs
StatePublished - Apr 5 2024

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Keywords

  • fusion plasma
  • plasma confinement
  • plasma instabilities

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