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1. Turbulent Magnetogenesis in a Collisionless Plasma

   https://doi.org/10.3847/2041-8213/ac36cf  

   Pucci, F.; Viviani, M.; Valentini, F.; Lapenta, G.; Matthaeus, W. H.; Servidio, S. (November 2021, The Astrophysical journal)

   We demonstrate an efficient mechanism for generating magnetic fields in turbulent, collisionless plasmas. By using fully kinetic, particle-in-cell simulations of an initially nonmagnetized plasma, we inspect the genesis of magnetization, in a nonlinear regime. The complex motion is initiated via a Taylor–Green vortex, and the plasma locally develops strong electron temperature anisotropy, due to the strain tensor of the turbulent flow. Subsequently, in a domino effect, the anisotropy triggers a Weibel instability, localized in space. In such active wave–particle interaction regions, the seed magnetic field grows exponentially and spreads to larger scales due to the interaction with the underlying stirring motion. Such a self-feeding process might explain magnetogenesis in a variety of astrophysical plasmas, wherever turbulence is present. 

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2. Investigation of high field plasma dynamics in a laser-produced plasma expanding into a background gas

   https://doi.org/10.1063/5.0193271  

   White, Z K; Xu, K G; Thakur, S Chakraborty (April 2024, Physics of Plasmas)

   This paper presents an overview of experimental results of a laser-produced plasma expanding into a background gas, immersed within a large range of highly uniform magnetic fields (of up to 3 T), that are transverse to the expanding plasma. We used intensified gated imaging to capture the expansion of the plasma across and along the magnetic field lines to observe the spatiotemporal expansion dynamics for different magnetic field strengths. We observe changes in the perpendicular and parallel dynamics of the laser-produced plasmas expansion at high magnetic field. In addition, our results have also indicated the presence of electron-ion hybrid instabilities at relatively high pressures (100 mTorr) and relatively high magnetic field strengths (2 T), in accordance with theoretical calculations. 

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3. Magnetic field imaging in a laboratory plasma

   https://doi.org/10.1063/5.0052957  

   Gilbert, T_J; Stevenson, K_J; Paul, M_C; Steinberger, T_E; Scime, E_E (May 2021, AIP Advances)

   In laboratory plasmas, arrays of probes have typically been used to measure the evolution of the magnetic field topology. Here, we present initial image-based measurements of the magnetic topology in a low-temperature plasma using a purely optical diagnostic. Laser induced fluorescence measurements of neutral velocity distribution functions are made using a fast camera, imaging the Zeeman splitting of σ-peaks in neutral argon. The separation of σ-peaks provides spatially resolved magnetic field magnitude measurements with a detection threshold on the order of 10 G. 

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4. Controlled plasma–droplet interactions: a quantitative study of OH transfer in plasma–liquid interaction

   https://doi.org/10.1088/1361-6595/aba988  

   Oinuma, Gaku; Nayak, Gaurav; Du, Yanjun; Bruggeman, Peter J (September 2020, Plasma Sources Science and Technology)

   null (Ed.)
5. Characterization of meter-scale Bessel beams for plasma formation in a plasma wakefield accelerator

   https://doi.org/10.18429/JACoW-IPAC2024-TUPS82  

   Nichols, Travis; Litos, Michael; Ariniello, Robert; Holtzapple, Robert; Gessner, Spencer; Lee, Valentina (January 2024, JACoW Publishing)

   Pilat, Fulvia; Fischer, Wolfram; Saethre, Robert; Anisimov, Petr; Andrian, Ivan (Ed.)

   A large challenge with Plasma Wakefield Acceleration lies in creating a plasma with a profile and length that properly match the electron beam. Using a laser-ionized plasma source provides control in creating an appropriate plasma density ramp. Additionally, using a laser-ionized plasma allows for an accelerator to run at a higher repetition rate. At the Facility for Advanced Accelerator Experimental Tests, at SLAC National Accelerator Laboratory, we ionize hydrogen gas with a 225 mJ, 50 fs, 800 nm laser pulse that passes through an axicon lens, imparting a conical phase on the pulse that produces a focal spot with an intensity distribution described radially by a Bessel function. This paper overviews the diagnostic tests used to characterize and optimize the focal spot along the meter-long focus. In particular, we observe how wavefront aberrations in the laser pulse impact the peak intensity of the focal spot. Furthermore, we discuss the impact of nonlinear effects caused by a 6 mm, CaF2 vacuum window in the laser beam line. 

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