Magnetohydrodynamic instabilities in radial foil configurations

Gourdain, P. A.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; Pikuz, S. A.; Seyler, C. E.; Shelkovenko, T. C.; Knapp, Patrick

doi:10.1063/1.3677887

Cited by 9 publications

(7 citation statements)

References 14 publications

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“…As time progresses, a plasma bubble forms, then expands into the low density plasma above the foil. Kink instabilities 11 disrupt the column at the center of the bubble which quickly breaks apart. While reproducibility of the plasma bubble phase is not guaranteed due to instabilities, the plasma jet phase reproduces nicely from shot to shot as long as current drive waveforms are similar.…”

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confidence: 99%

Impact of the Hall Effect on High-Energy-Density Plasma Jets

Gourdain

Seyler

2013

Phys. Rev. Lett.

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Using a 1-MA, 100 ns-rise-time pulsed power generator, radial foil configurations can produce strongly collimated plasma jets. The resulting jets have electron densities on the order of 10(20) cm(-3), temperatures above 50 eV and plasma velocities on the order of 100 km/s, giving Reynolds numbers of the order of 10(3), magnetic Reynolds and Péclet numbers on the order of 1. While Hall physics does not dominate jet dynamics due to the large particle density and flow inside, it strongly impacts flows in the jet periphery where plasma density is low. As a result, Hall physics affects indirectly the geometrical shape of the jet and its density profile. The comparison between experiments and numerical simulations demonstrates that the Hall term enhances the jet density when the plasma current flows away from the jet compared to the case where the plasma current flows towards it.

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confidence: 99%

Impact of the Hall Effect on High-Energy-Density Plasma Jets

Gourdain

Seyler

2013

Phys. Rev. Lett.

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“…20, 21 from [17]. Current-driven instabilities of the central jet column were also experimentally observed and computationally simulated in [250] for magnetic tower jets formed in radial foil configurations.…”

Section: Magnetically Dominated Jets Using Pulsed Power Machinesmentioning

confidence: 91%

Persistent mysteries of jet engines, formation, propagation, and particle acceleration: have they been addressed experimentally?

Blackman,

Lebedev

2020

Preprint

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The physics of astrophysical jets can be divided into three regimes: (i) engine and launch (ii) propagation and collimation, (iii) dissipation and particle acceleration. Since astrophysical jets comprise a huge range of scales and phenomena, practicality dictates that most studies of jets intentionally or inadvertently focus on one of these regimes, and even therein, one body of work may be simply boundary condition for another. We first discuss long standing persistent mysteries that pertain the physics of each of these regimes, independent of the method used to study them. This discussion makes contact with frontiers of plasma astrophysics more generally. While observations theory, and simulations, and have long been the main tools of the trade, what about laboratory experiments? Jet related experiments have offered controlled studies of specific principles, physical processes, and benchmarks for numerical and theoretical calculations. We discuss what has been done to date on these fronts. Although experiments have indeed helped us to understand certain processes, proof of principle concepts, and benchmarked codes, they have yet to solved an astrophysical jet mystery on their own. A challenge is that experimental tools used for jet-related experiments so far, are typically not machines originally designed for that purpose, or designed with specific astrophysical mysteries in mind. This presents an opportunity for a different way of thinking about the development of future platforms: start with the astrophysical mystery and build an experiment to address it.

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“…This difference cannot be only supported by pure Hall MHD arguments as shown from previous research. 18 Radial plasma flows do converge towards the Z-pinch jet and may have a stabilizing effect. Reversing the current direction could increase radial flows, which would tend to mitigate the formation and growth of kink instabilities.…”

Section: The Z-pinch Jetmentioning

confidence: 97%

The impact of Hall physics on magnetized high energy density plasma jets

et al. 2014

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Hall physics is often neglected in high energy density plasma jets due to the relatively high electron density of such jets (ne ∼ 1019 cm−3). However, the vacuum region surrounding the jet has much lower densities and is dominated by Hall electric field. This electric field redirects plasma flows towards or away from the axis, depending on the radial current direction. A resulting change in the jet density has been observed experimentally. Furthermore, if an axial field is applied on the jet, the Hall effect is enhanced and ignoring it leads to serious discrepancies between experimental results and numerical simulations. By combining high currents (∼1 MA) and magnetic field helicity (15° angle) in a pulsed power generator such as COBRA, plasma jets can be magnetized with a 10 T axial field. The resulting field enhances the impact of the Hall effect by altering the density profile of current-free plasma jets and the stability of current-carrying plasma jets (e.g., Z-pinches).

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Magnetohydrodynamic instabilities in radial foil configurations

Cited by 9 publications

References 14 publications

Impact of the Hall Effect on High-Energy-Density Plasma Jets

Impact of the Hall Effect on High-Energy-Density Plasma Jets

Persistent mysteries of jet engines, formation, propagation, and particle acceleration: have they been addressed experimentally?

The impact of Hall physics on magnetized high energy density plasma jets

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