A new method to suppress the Rayleigh–Taylor instability in a linear device

Abstract

Rayleigh–Taylor instability (RTI) is a primary hurdle for many different fusion approaches, most of which rely on external pressure to stabilize the plasma by impeding plasma displacement. In this paper, we report a novel method that utilizes a rotating magnetic field (RMF) to drive an azimuthal electron current to reduce the charge separation caused by RTI. The fluctuation measured in the central cell of the mirror device, approximately half a device length away from the RMF, is identified as the m=1 mode and is suppressed by the RMF in the plug cell. The azimuthal electric fields of the fluctuation are found to decrease to almost zero, and the radial confinement is improved by more than a factor of ten. The separation of the RMF region from the central cell makes this stabilization method unique because the RMF, which can complicate the local magnetic field lines, has little influence on the magnetic field configuration in the central cell. This study may shed light on the use of resonant magnetic perturbations in tokamaks as well as on stabilization methods for many other fusion experiments.

Physics basis for the Wisconsin HTS Axisymmetric Mirror (WHAM)

“…1987), rotating magnetic fields (Seemann, Be'ery & Fisher 2018; Zhu et al. 2019), close fitting conducting shells (Kesner 1985; Beklemishev 2016; Kotelnikov et al. 2022) and feedback (Prater 1971; Be'ery, Seemann & Fisher 2014; Be'ery & Seemann 2015; Beklemishev 2017).…”

“…The strategy for WHAM will be to use the known physics of FLR and vortex stabilization first, and later to test other promising techniques that may extrapolate better to future fusion reactors. Many ideas have been suggested and demonstrated to work over the past 50 years, (summarized well by Ryutov et al 2011), including the use of good curvature (Mirnov & Ryutov 1979;Bagryansky et al 2011), cusp boundaries (Prater 1971;Ferron et al 1983;Kotelnikov et al 2019), ponderomotive effects (Ferron et al 1987), rotating magnetic fields (Seemann, Be'ery & Fisher 2018; Zhu et al 2019), close fitting conducting shells (Kesner 1985;Beklemishev 2016;Kotelnikov et al 2022) and feedback (Prater 1971;Be'ery, Seemann & Fisher 2014;Be'ery & Seemann 2015;Beklemishev 2017).…”

Prospects for a high-field, compact break-even axisymmetric mirror (BEAM) and applications

“…1987; Seemann, Be'ery & Fisher 2018; Zhu et al. 2019). The suggested stabilization mechanisms range from ponderomotive force to side-band coupling, diamagnetic pressure and electron current drive.…”

Plasma Waves and Rayleigh–Taylor Instability: Theory and Application

“…Zhu et al presented a method to run an azimuthal electron current that utilizes a rotating magnetic field to decrease the charge separation due to RTI. The azimuthal electric field of the fluctuation approaches to zero [15]. The mathematical homotopy perturbation method is employed to solve complex nonlinear differential equations.…”