Particle velocity distribution in a three-dimensional dusty plasma under microgravity conditions

Liu, Bin; Goree, J.; Pustylnik, Mikhail; Thomas, Hubertus M.; Фортов, В. Е.; Lipaev, A. M.; Usachev, A. D.; Molotkov, V. I.; Petrov, Fedor; Thoma, Markus H.

doi:10.1063/1.5020393

Cited by 9 publications

(6 citation statements)

References 11 publications

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“…The profiles are characteristic of a strongly correlated collisionless electron bunch trapped in the bubble quadratic potential and immersed in a laser radiation field [31]. Prior observations of kappa-distributed electrons have been made mainly in space or dusty plasmas [32][33][34][35]. Under optimized conditions using circularly polarized drive pulses, we obtain quasi mono-energetic electron beams with energy 𝐸 𝑏 ~15 MeV and ∆𝜃 𝑑𝑖𝑣 < 7 mrad FWHM divergence.…”

Section: Introductionmentioning

confidence: 93%

Laser-Accelerated, Low-Divergence 15-MeV Quasimonoenergetic Electron Bunches at 1 kHz

Salehi

Railing

et al. 2021

Phys. Rev. X

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We demonstrate laser wakefield acceleration of quasi-monoenergetic electron bunches up to 15 MeV at 1 kHz repetition rate with 2.5 pC charge per bunch and a core with <7 mrad beam divergence. Acceleration is driven by 5 fs, < 2.7 mJ laser pulses incident on a thin, near-critical density hydrogen gas jet. Low beam divergence is attributed to reduced sensitivity to laser carrier envelope phase slip, achieved in two ways using laser polarization and gas jet control: (1) electron injection into the wake on the gas jet's plasma density downramp, and (2) use of circularly polarized drive pulses. Under conditions of mild wavebreaking in the downramp, electron beam profiles have a 2D Lorentzian shape consistent with a 𝜅 ("kappa") electron energy distribution. Such distributions had previously been observed only in space or dusty plasmas. We attribute this shape to the strongly correlated collisionless bunch confined by the quadratic wakefield bubble potential, where transverse velocity space diffusion is imparted to the bunch by the red-shifted laser field in the bubble.

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Section: Introductionmentioning

confidence: 93%

Laser-Accelerated, Low-Divergence 15-MeV Quasimonoenergetic Electron Bunches at 1 kHz

Salehi

Railing

et al. 2021

Phys. Rev. X

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“…In Fig. 2a, we confront them with independent observations 40 of velocity distributions of a plasma under micro-gravity conditions, obtained through the PK-4 instrument on-board the International Space Station (ISS), that clearly exhibit a non-Boltzmann behavior. We show the best-fits obtained by a nonlinear regression method based on the Levenberg-Marquardt algorithm 50,51 (also known as the damped least-squares method), for the χ 2 and the log-normal universality classes, while we disregard the inverse-χ 2 class, which fails to describe the high-energy part of the observational data, since it exhibits an exponential decay.…”

Section: Nonequilibrium Stationary Distributionsmentioning

confidence: 99%

Fingerprints of nonequilibrium stationary distributions in dispersion relations

Ourabah

2021

Sci Rep

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Distributions different from those predicted by equilibrium statistical mechanics are commonplace in a number of physical situations, such as plasmas and self-gravitating systems. The best strategy for probing these distributions and unavailing their origins consists in combining theoretical knowledge with experiments, involving both direct and indirect measurements, as those associated with dispersion relations. This paper addresses, in a quite general context, the signature of nonequilibrium distributions in dispersion relations. We consider the very general scenario of distributions corresponding to a superposition of equilibrium distributions, that are well-suited for systems exhibiting only local equilibrium, and discuss the general context of systems obeying the combination of the Schrödinger and Poisson equations, while allowing the Planck’s constant to smoothly go to zero, yielding the classical kinetic regime. Examples of media where this approach is applicable are plasmas, gravitational systems, and optical molasses. We analyse in more depth the case of classical dispersion relations for a pair plasma. We also discuss a possible experimental setup, based on spectroscopic methods, to directly observe these classes of distributions.

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“…2017), particle kinetics (Liu et al. 2018), structural phase transitions (Dietz et al. 2018) and dust density waves (Jaiswal et al.…”

Section: Introductionmentioning

confidence: 99%

Effect of ionization waves on dust chain formation in a DC discharge

et al. 2021

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An interesting aspect of complex plasma is its ability to self-organize into a variety of structural configurations and undergo transitions between these states. A striking phenomenon is the isotropic-to-string transition observed in electrorheological complex plasma under the influence of a symmetric ion wake field. Such transitions have been investigated using the Plasma Kristall-4 (PK-4) microgravity laboratory on the International Space Station. Recent experiments and numerical simulations have shown that, under PK-4-relevant discharge conditions, the seemingly homogeneous direct current discharge column is highly inhomogeneous, with large axial electric field oscillations associated with ionization waves occurring on microsecond time scales. A multi-scale numerical model of the dust–plasma interactions is employed to investigate the role of the electric field in the charge of individual dust grains, the ion wake field and the order of string-like structures. Results are compared with those for dust strings formed in similar conditions in the PK-4 experiment.

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Particle velocity distribution in a three-dimensional dusty plasma under microgravity conditions

Cited by 9 publications

References 11 publications

Laser-Accelerated, Low-Divergence 15-MeV Quasimonoenergetic Electron Bunches at 1 kHz

Laser-Accelerated, Low-Divergence 15-MeV Quasimonoenergetic Electron Bunches at 1 kHz

Fingerprints of nonequilibrium stationary distributions in dispersion relations

Effect of ionization waves on dust chain formation in a DC discharge

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