Active feedback stabilization of the flute instability in a mirror machine using field-aligned coils

Lifshitz, Assa; Be'ery, Ilan; Fisher, A.; Ron, A.; Fruchtman, A.

doi:10.1088/0029-5515/52/12/123008

Cited by 3 publications

(2 citation statements)

References 9 publications

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“…One possible control mechanism may lie in the plasma displacement induced by a magnetosonic wave. Compressional Alfvén waves produced by dedicated magnetic coils have for example been suggested to stabilize plasmas in mirror machines 37 . Yet, soliton propagation, and more generally wave propagation, in laboratory plasmas differs from the situation considered in space plasmas in that laboratory plasmas are of finite spatial extension and bounded.…”

Section: Introductionmentioning

confidence: 99%

Cumulative displacement induced by a magnetosonic soliton bouncing in a bounded plasma slab

2018

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The passage of a magnetosonic (MS) soliton in a cold plasma leads to the displacement of charged particles in the direction of a compressive pulse and in the opposite direction of a rarefaction pulse. In the overdense plasma limit, the displacement induced by a weakly nonlinear MS soliton is derived analytically. This result is then used to derive an asymptotic expansion for the displacement resulting from the bouncing motion of a MS soliton reflected back and forth in a vacuum-bounded cold plasma slab. Particles' displacement after the pulse energy has been lost to the vacuum region is shown to scale as the ratio of light speed to Alfvén velocity. Results for the displacement after a few MS soliton reflections are corroborated by particle-in-cell simulations.

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Section: Introductionmentioning

confidence: 99%

Cumulative displacement induced by a magnetosonic soliton bouncing in a bounded plasma slab

2018

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“…The key issue in magnetic confinement of hot plasmas is coping with the various instabilities, which disrupt the shape of the plasma and increase the plasma thermal energy and particles losses. Active feedback stabilization using non-axisymmetric magnetic actuators have been proposed for mirror machine [1][2][3][4] but was never realized. In tokamaks and other toroidal machines, magnetic feedback have been used for many years.…”

Section: Introductionmentioning

confidence: 99%

Microseconds-scale magnetic actuators system for plasma feedback stabilization

2016

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Many magnetic confinement machines use active feedback stabilization with magnetic actuators. We present a novel magnetic actuators system with a response time much faster than previous ones, making it capable of coping with the fast plasma instabilities. The system achieved a response time of 3 µs with maximal current of 500 A in a coil with inductance of 5.2 µH. The system is based on commercial solid-state switches and FPGA state machine, making it easily scalable to higher currents or higher inductivity.

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

et al. 2019

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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.

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Active feedback stabilization of the flute instability in a mirror machine using field-aligned coils

Cited by 3 publications

References 9 publications

Cumulative displacement induced by a magnetosonic soliton bouncing in a bounded plasma slab

Cumulative displacement induced by a magnetosonic soliton bouncing in a bounded plasma slab

Microseconds-scale magnetic actuators system for plasma feedback stabilization

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

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