Supersonic plasma turbulence in the laboratory

White, Thomas G.; Oliver, M.; Mabey, P.; Kühn-Kauffeldt, M.; Bott, A. F. A.; Döhl, Leonard N. K.; Bell, A. R.; Bingham, R.; Clarke, R.J.; Foster, J. M.; Giacinti, Gwenael; Graham, Peter W.; Heathcote, R.; Kœnig, M.; Kuramitsu, Yasuhiro; Lamb, D. Q.; Meinecke, J.; Michel, Th.; Miniati, Francesco; Notley, M.; Reville, Brian; Ryu, Dongsu; Sarkar, S.; Sakawa, Y.; Selwood, Matthew; Squire, Jonathan; Scott, Robert H.; Tzeferacos, Petros; Woolsey, N. C.; Schekochihin, A. A.; Gregori, G.

doi:10.1038/s41467-019-09498-y

Cited by 31 publications

(22 citation statements)

References 30 publications

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“…Banerjee & Galtier (2013) attribute those results to the variability of the energy cascade rate due to compressibility. As shown in Figure 4(d), the density spectra at MHD scales flatten with increasing M turb , which is consistent with previous numerical and experimental studies in the supersonic regime (Kritsuk et al 2007;Konstandin et al 2016;White et al 2019). However, velocity spectral indices at MHD scales also flatten with the increasing of M turb , in contrast to the results in supersonic turbulence Kritsuk et al 2007).…”

Section: From the Bow Shock To The Magnetopausesupporting

confidence: 90%

Evolution of the Earth’s Magnetosheath Turbulence: A Statistical Study Based on MMS Observations

Jiang

Wang

et al. 2020

ApJL

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Composed of shocked solar wind, the Earth's magnetosheath serves as a natural laboratory to study the transition of turbulence from low Alfvén Mach number, M A , to high M A. The simultaneous observations of magnetic field and plasma moments with unprecedented high temporal resolution provided by NASA's Magnetospheric Multiscale Mission (MMS) enable us to study the magnetosheath turbulence at both magnetohydrodynamics (MHD) and sub-ion scales. Based on 1841 burst-mode segments of MMS-1 from 2015 September to 2019 June, comprehensive patterns of the spatial evolution of magnetosheath turbulence are obtained: (1) from the subsolar region to the flanks, M A increases from <1 to >5. At MHD scales, the spectral indices of the magnetic-field and velocity spectra present a positive and negative correlation with M A. However, no obvious correlations between the spectral indices and M A are found at sub-ion scales. (2) From the bow shock to the magnetopause, the turbulent sonic Mach number, M turb , generally decreases from >0.4 to <0.1. All spectra steepen at MHD scales and flatten at sub-ion scales, representing positive/negative correlations with M turb. The break frequency increases by 0.1 Hz when approaching the magnetopause for the magnetic-field and velocity spectra, while it remains at 0.3 Hz for the density spectra. (3) In spite of minor differences, similar results are found for the quasi-parallel and quasi-perpendicular magnetosheath. In addition, such spatial evolution of magnetosheath turbulence is found to be independent of the upstream solar wind conditions, e.g., the averaged Z-component of the interplanetary magnetic field and solar wind speed.

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Section: From the Bow Shock To The Magnetopausesupporting

confidence: 90%

Evolution of the Earth’s Magnetosheath Turbulence: A Statistical Study Based on MMS Observations

Jiang

Wang

et al. 2020

ApJL

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“…Because fluctuating density in a subsonic plasma behaves as a passive scalar (43), this in turn allows for the measurement of the velocity power spectrum (35). The result of such a calculation applied to Figure 4b is shown in Figure 4d: the spectrum extends across the full range of resolved wavenumbers and, for characteristic wavenumbers 2π/L k < kres = 127 mm −1 , the spectral slope is consistent with the Kolmogorov power law, as expected for a turbulent, subsonic plasma (44).…”

Section: R a F Tmentioning

confidence: 61%

Time-resolved turbulent dynamo in a laser plasma

Bott

Tzeferacos

Chen

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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Understanding magnetic-field generation and amplification in turbulent plasma is essential to account for observations of magnetic fields in the universe. A theoretical framework attributing the origin and sustainment of these fields to the so-called fluctuation dynamo was recently validated by experiments on laser facilities in low-magnetic-Prandtl-number plasmas (Pm<1). However, the same framework proposes that the fluctuation dynamo should operate differently when Pm≳1, the regime relevant to many astrophysical environments such as the intracluster medium of galaxy clusters. This paper reports an experiment that creates a laboratory Pm≳1 plasma dynamo. We provide a time-resolved characterization of the plasma’s evolution, measuring temperatures, densities, flow velocities, and magnetic fields, which allows us to explore various stages of the fluctuation dynamo’s operation on seed magnetic fields generated by the action of the Biermann-battery mechanism during the initial drive-laser target interaction. The magnetic energy in structures with characteristic scales close to the driving scale of the stochastic motions is found to increase by almost three orders of magnitude and saturate dynamically. It is shown that the initial growth of these fields occurs at a much greater rate than the turnover rate of the driving-scale stochastic motions. Our results point to the possibility that plasma turbulence produced by strong shear can generate fields more efficiently at the driving scale than anticipated by idealized magnetohydrodynamics (MHD) simulations of the nonhelical fluctuation dynamo; this finding could help explain the large-scale fields inferred from observations of astrophysical systems.

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“…Whereas truly detrimental for all ICF approachs, the degree of nonlinearity in HED plasma flows is approaching fully developed turbulence. However, this turbulence is still inferred indirectly with rather strong assumptions [182]. We still miss the kind of particle velocimetry measurements routinely used in classical hydrodynamics to measure velocity distribution functions.…”

Section: Discussionmentioning

confidence: 99%

Recent progress in quantifying hydrodynamics instabilities and turbulence in inertial confinement fusion and high-energy-density experiments

Casner

2020

Phil. Trans. R. Soc. A.

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Since the seminal paper of Nuckolls triggering the quest of inertial confinement fusion (ICF) with lasers, hydrodynamic instabilities have been recognized as one of the principal hurdles towards ignition. This remains true nowadays for both main approaches (indirect drive and direct drive), despite the advent of MJ scale lasers with tremendous technological capabilities. From a fundamental science perspective, these gigantic laser facilities enable also the possibility to create dense plasma flows evolving towards turbulence, being magnetized or not. We review the state of the art of nonlinear hydrodynamics and turbulent experiments, simulations and theory in ICF and high-energy-density plasmas and draw perspectives towards in-depth understanding and control of these fascinating phenomena. This article is part of a discussion meeting issue ‘Prospects for high gain inertial fusion energy (part 2)’.

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Supersonic plasma turbulence in the laboratory

Cited by 31 publications

References 30 publications

Evolution of the Earth’s Magnetosheath Turbulence: A Statistical Study Based on MMS Observations

Evolution of the Earth’s Magnetosheath Turbulence: A Statistical Study Based on MMS Observations

Time-resolved turbulent dynamo in a laser plasma

Recent progress in quantifying hydrodynamics instabilities and turbulence in inertial confinement fusion and high-energy-density experiments

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