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| Open AccessPlasma electron acceleration driven by a long-wave-infrared laser
The laser pulses that drive most laser wakefield accelerators have wavelengths near 1 micrometer and peak power > 100 terawatts. Here, the authors drive plasma wakes with 10 micrometer, 2-terawatt pulses, yielding relativistic electron beams with a collimated, narrow-energy-bandwidth component.
- R. Zgadzaj
- , J. Welch
- & M. C. Downer
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Article
| Open AccessHighest fusion performance without harmful edge energy bursts in tokamak
Damaging energy bursts in a tokamak are a major obstacle to achieving stable high-fusion performance. Here, the authors demonstrate the use of adaptive and machine-learning control to optimize the 3D magnetic field to prevent edge bursts and maximize fusion performance in two different fusion devices, DIII-D and KSTAR.
- S. K. Kim
- , R. Shousha
- & E. Kolemen
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| Open AccessEnhancements of electric field and afterglow of non-equilibrium plasma by Pb(ZrxTi1−x)O3 ferroelectric electrode
The physics of how ferroelectric materials enhance plasma properties and discharge is unclear. Here, the authors enhance surface charge, electric field and afterglow of nonequilibrium plasma by ferroelectric barrier discharge with evidence from laser diagnostics.
- Yijie Xu
- , Ning Liu
- & Yiguang Ju
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Article
| Open AccessThe impact of low-mode symmetry on inertial fusion energy output in the burning plasma state
Recent improvements in the indirect-drive inertial confinement fusion experiments include the achievement of burning plasma state. Here the authors report the scaling of neutron yield in a burning plasma of Deuterium-Tritium fusion reaction by including the mode-2 asymmetry.
- J. E. Ralph
- , J. S. Ross
- & G. B. Zimmerman
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| Open AccessA control oriented strategy of disruption prediction to avoid the configuration collapse of tokamak reactors
Confining plasma and managing disruptions in tokamak devices is a challenge. Here the authors demonstrate a method predicting and possibly preventing disruptions and macroscopic instabilities in tokamak plasma using data from JET.
- Andrea Murari
- , Riccardo Rossi
- & Michela Gelfusa
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| Open AccessChorus wave power at the strong diffusion limit overcomes electron losses due to strong diffusion
Strong diffusion limit is the maximum rate of electron loss into the atmosphere from Earth’s radiation belts. Here, the authors show scaling up chorus wave power to the strong diffusion limit causes rapid acceleration of electrons, sufficient to outweigh the losses due to strong diffusion.
- T. A. Daggitt
- , R. B. Horne
- & J. M. Albert
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Article
| Open AccessExperimental study on chorus emission in an artificial magnetosphere
Plasma created in laboratory are useful to understand the properties of atmospheric and space plasma. Here the authors report a laboratory plasma experiment in a dipole magnetic field to show the excitation of chirping whistler waves, i.e. chorus emission.
- Haruhiko Saitoh
- , Masaki Nishiura
- & Zensho Yoshida
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| Open AccessTailoring tokamak error fields to control plasma instabilities and transport
Error fields in tokamak appear due to the imperfections and misalignment of the coils generating magnetic field. Here the authors demonstrate use of error field correction to control the plasma transport and instabilities in a tokamak - KSTAR.
- SeongMoo Yang
- , Jong-Kyu Park
- & Won-Ha Ko
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Article
| Open AccessElectron scale coherent structure as micro accelerator in the Earth’s magnetosheath
Both particle and wave energy exist in plasma and energy transfer leads to many interesting phenomena like turbulence, particle acceleration. Here the authors show electron-scale coherent structure resulting from energy transfer in magnetosheath using a model and data from Magnetospheric Multiscale Mission.
- Zi-Kang Xie
- , Qiu-Gang Zong
- & Per-Arne Lindqvist
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| Open AccessGlobal-scale magnetosphere convection driven by dayside magnetic reconnection
A fundamental feature of planetary magnetospheres is internal convection induced by surrounding solar wind. Here, authors offer insights into the interplay among solar wind, magnetosphere, and ionosphere, and evidence a dayside-driven convection pattern linked to magnetic-field-aligned currents.
- Lei Dai
- , Minghui Zhu
- & Graziella Branduardi-Raymont
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| Open AccessMagnetosheath jets at Jupiter and across the solar system
Jets have been found in Earth’s magnetosheath for two decades and, more recently, also in Mars. Yet, their universal existence in planetary magnetosheath remains an open question. Here, authors report the presence of anti-sunward and sunward jets at Jupiter and compare them to Earth and Mars.
- Yufei Zhou
- , Savvas Raptis
- & Lan Ma
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Article
| Open AccessEnergy transfer of imbalanced Alfvénic turbulence in the heliosphere
How and via which mechanism the energy transfers between scales in imbalanced Alfvénic turbulence is an open question. Here, the authors show that the energy transfer of imbalanced Alfvénic turbulence is completed by coherent interactions between Alfvén waves and co-propagating anomalous fluctuations.
- Liping Yang
- , Jiansen He
- & Ziqi Wu
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Article
| Open AccessObservational evidence of accelerating electron holes and their effects on passing ions
Electron holes with drift speeds comparable to local ion thermal velocity are called slow electron holes. Here, the authors show slow electron holes with non-zero acceleration can cause net velocity change of ions passing through.
- Yue Dong
- , Zhigang Yuan
- & J. L. Burch
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Article
| Open AccessCharge decay in the spatial afterglow of plasmas and its impact on diffusion regimes
Plasmas have different properties at the boundaries as compared to the bulk which has important implications for applications. Here, the authors study charge decay in a spatial afterglow by both experimental diagnostics and modeling to reveal a transition from ambipolar to free diffusion.
- Nabiel H. Abuyazid
- , Necip B. Üner
- & R. Mohan Sankaran
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Article
| Open AccessEfficiently accelerated free electrons by metallic laser accelerator
Accelerated electron beams are potentially useful for imaging and different type of light sources. Here the authors demonstrate electron acceleration using metallic laser acceleration with efficiency comparable to that of dielectric laser accelerators.
- Dingguo Zheng
- , Siyuan Huang
- & Jianqi Li
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Article
| Open AccessExperimental confirmation of driving pressure boosting and smoothing for hybrid-drive inertial fusion at the 100-kJ laser facility
In laser-driven inertial fusion, finding optimal driving pressure is a major challenge. Here, the authors use a 100 kJ SG laser and a hybrid-drive scheme to demonstrate such driving pressure with the help of the direct-drive laser such that the indirect-drive radiation ablation pressure is turned into a well-smoothed hybrid-drive pressure much greater than the radiation ablation pressure.
- Ji Yan
- , Jiwei Li
- & Shaoping Zhu
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| Open AccessUltra-short pulse laser acceleration of protons to 80 MeV from cryogenic hydrogen jets tailored to near-critical density
Laser-produced plasma can be used for particle acceleration in different schemes. Here the authors demonstrate proton acceleration from the intense ultrashort laser pulse interaction with micron-sized cryogenic hydrogen jet.
- Martin Rehwald
- , Stefan Assenbaum
- & Karl Zeil
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Article
| Open AccessRefractive plasma optics for relativistic laser beams
Intense laser interaction with matter creates plasma which can act as a nonlinear optical medium. Here the authors demonstrate plasma as a refractive optics for relativistic intensity radiation, evident by the acceleration of multiple electron beams from a single laser pulse passing through the plasma.
- Omri Seemann
- , Yang Wan
- & Victor Malka
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Article
| Open AccessUltrabroadband sound control with deep-subwavelength plasmacoustic metalayers
Controlling audible sound requires inherently broadband and subwavelength acoustic solutions. Exploiting the unique physics of plasmacoustic metalayers, we experimentally demonstrate versatile and tunable sound control over a wide frequency range.
- Stanislav Sergeev
- , Romain Fleury
- & Hervé Lissek
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| Open AccessUltra-high-resolution observations of persistent null-point reconnection in the solar corona
Magnetic reconnection is a fundamental energy release mechanism in space and laboratory plasmas. Here, the authors show persistent magnetic null-point reconnection in the solar corona at a scale of about 390 km.
- X. Cheng
- , E. R. Priest
- & S. Parenti
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| Open AccessAttosecond-Angstrom free-electron-laser towards the cold beam limit
Free-electron lasers (FELs) can produce bright X-ray pulses, but require high quality electron beams. Here the authors show how to generate and preserve ultrabright electron beams from plasma-based accelerators for ultra-compact, high-brightness X-ray FELs.
- A. F. Habib
- , G. G. Manahan
- & B. Hidding
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| Open AccessFirst measurements of p11B fusion in a magnetically confined plasma
The fusion reaction involving proton (p) and boron (11B) has unique advantages over deuterium-tritium (DT) fusion in terms of number of neutrons generated and availability of the fuel components. Here the authors demonstrate the (p,11B) fusion reaction in a magnetically confined plasma at the Large Helical Device.
- R. M. Magee
- , K. Ogawa
- & M. Osakabe
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| Open AccessEquilibrium selection via current sheet relaxation and guide field amplification
Magnetized plasmas display continuous spectra of current-sheet equilibria. How they select a particular equilibrium is not well understood. Now, equilibrium selection in magnetized plasmas is studied by analytical theory, particle-in-cell simulations and spacecraft observations, highlighting the role of current-sheet relaxation processes.
- Young Dae Yoon
- , Deirdre E. Wendel
- & Gunsu S. Yun
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Article
| Open AccessAccurate temperature diagnostics for matter under extreme conditions
Existing methods for temperature estimation of warm dense matter rely on model calculations. Here the authors report a method to extract the temperature of complex materials that is previously only inferred by using model calculations.
- Tobias Dornheim
- , Maximilian Böhme
- & Jan Vorberger
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Article
| Open AccessMicrowave imaging of quasi-periodic pulsations at flare current sheet
Quasi-periodic pulsations (QPPs) are frequently detected in solar and stellar flares, but the underlying physical mechanisms are still to be ascertained. Here, the authors show microwave QPPs during a solar flare originating from quasi-periodic magnetic reconnection at the flare current sheet.
- Yuankun Kou
- , Xin Cheng
- & Mingde Ding
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Article
| Open AccessProbing atomic physics at ultrahigh pressure using laser-driven implosions
Atoms and molecules under extreme temperature and pressure can be investigated using dense plasmas achieved by laser-driven implosion. Here the authors report spectral change of copper in billions atmosphere pressure that can only be explained by a self-consistent approach.
- S. X. Hu
- , David T. Bishel
- & Timothy Walton
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Article
| Open AccessObservation of a new type of self-generated current in magnetized plasmas
Fusion devices like tokamaks require plasma current to generate magnetic field for plasma confinement. Here the authors report an observation of a self-generated anomalous current that contributes up to 30% of the total current in the fusion plasma at KSTAR.
- Yong-Su Na
- , Jaemin Seo
- & Taik Soo Hahm
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Article
| Open AccessLaboratory evidence of magnetic reconnection hampered in obliquely interacting flux tubes
Magnetic reconnection acts as energy transfer process in plasma and induces processes like plasma heating, particle acceleration. Here the authors demonstrate the variation of magnetic reconnection between two flux tubes in the presence of external magnetic field.
- Simon Bolaños
- , Andrey Sladkov
- & Julien Fuchs
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Article
| Open AccessThe supernova remnant SN 1006 as a Galactic particle accelerator
It is known that cosmic rays could be accelerated by shock waves in supernova (SN) remnants. Here, the authors show that SN 1006 remnant is an efficient source of cosmic rays, providing observational support for the quasi-parallel acceleration mechanism.
- Roberta Giuffrida
- , Marco Miceli
- & Giovanni Peres
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| Open AccessIdentification of a non-axisymmetric mode in laboratory experiments searching for standard magnetorotational instability
Magnetohydrodynamic instabilities are related to different characteristics and behavior of fluids. Here the authors report an experiment and simulation combined study of a global non-axisymmetric MHD instability that exists at sufficiently large rotation rates and intermediate magnetic field strengths.
- Yin Wang
- , Erik P. Gilson
- & Hantao Ji
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| Open AccessEnergy-selective confinement of fusion-born alpha particles during internal relaxations in a tokamak plasma
Confining plasma for fusion requires controlling many parameters. Here the authors report the existence of a narrow parameter space for the simultaneous confinement of energetic alpha particles and removal of slowed-down helium ash in a magnetically confined fusion plasma by using kinetic-magnetohydrodynamic hybrid simulations.
- A. Bierwage
- , K. Shinohara
- & S. Ide
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Article
| Open AccessGeneration of ultrahigh-brightness pre-bunched beams from a plasma cathode for X-ray free-electron lasers
Laser-produced plasma can be used for acceleration and tuning of particle beams. Here the authors discuss the generation of a bunched electron beam using simulations and its application to X-ray free-electron laser.
- Xinlu Xu
- , Fei Li
- & Warren B. Mori
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Article
| Open AccessMulti-scale turbulence simulation suggesting improvement of electron heated plasma confinement
Understanding the transport of the particles and fuel in the fusion plasma is fundamentally important. Here the authors report a cross-link interaction between electron- and ion-scale turbulences in plasma in terms of trapped electron mode and electron temperature gradient modes and their implication to fusion plasma.
- Shinya Maeyama
- , Tomo-Hiko Watanabe
- & Akihiro Ishizawa
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Article
| Open AccessDirect observations of anomalous resistivity and diffusion in collisionless plasma
It is suggested that waves can provide both diffusion and resistivity that can potentially support the reconnection electric field in low-density astrophysical plasmas. Here, the authors show, using direct spacecraft measurements, that the waves contribute to anomalous diffusion but do not contribute to the reconnection electric field.
- D. B. Graham
- , Yu. V. Khotyaintsev
- & K. Dokgo
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Article
| Open AccessProton stopping measurements at low velocity in warm dense carbon
Charged particle interaction and energy dissipation in plasma is fundamentally interesting. Here the authors study proton stopping in laser-produced plasma for the moderate to strong coupling with electrons.
- S. Malko
- , W. Cayzac
- & L. Volpe
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| Open AccessPlasma-induced surface cooling
When a plasma interacts with a surface, different thermal effects may arise. Here, the authors explore plasma interactions with a surface that produce a surface cooling effect.
- John A. Tomko
- , Michael J. Johnson
- & Patrick E. Hopkins
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Article
| Open AccessDemonstration of non-destructive and isotope-sensitive material analysis using a short-pulsed laser-driven epi-thermal neutron source
High-power laser beams can be used to accelerate neutron beams. Here the authors demonstrate the application of laser-driven neutron beams to neutron resonance spectroscopy and neutron resonance imaging.
- Marc Zimmer
- , Stefan Scheuren
- & Markus Roth
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Article
| Open AccessDownstream high-speed plasma jet generation as a direct consequence of shock reformation
Several mechanisms exist for formation of jets observed in Earth’s magnetosheath. Here, the authors show evidence of high-speed downstream flows generated at the Earth’s bow shock as a direct consequence of shock reformation, which is different than the proposed mechanisms.
- Savvas Raptis
- , Tomas Karlsson
- & Per-Arne Lindqvist
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| Open AccessVacuum laser acceleration of super-ponderomotive electrons using relativistic transparency injection
Compact electron accelerators based on laser-plasma acceleration scheme may be useful for future light sources, radiation therapy etc. Here the authors demonstrate electron acceleration in laser plasma interaction via vacuum laser acceleration and relativistic transparency injection.
- P. K. Singh
- , F.-Y. Li
- & S. Palaniyappan
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Article
| Open AccessTemperature relaxation in strongly-coupled binary ionic mixtures
Most plasmas are created in a nonequilibrium state and understanding the non-trivial pathway to equilibrium is critical for predicting their time-evolving properties. Here the authors discuss the ion-ion temperature relaxation in a dual-species ultracold neutral plasma.
- R. Tucker Sprenkle
- , L. G. Silvestri
- & S. D. Bergeson
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Article
| Open AccessForward-looking insights in laser-generated ultra-intense γ-ray and neutron sources for nuclear application and science
Laser-plasma interaction can provide alternative platform over conventional method for particle and photon beam generation. Here the authors demonstrate generation of gamma ray and neutron beams from intense laser interaction with near critical density plasma.
- M. M. Günther
- , O. N. Rosmej
- & N. E. Andreev
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Article
| Open AccessTime-resolved study of holeboring in realistic experimental conditions
Experimental measurements involving multiple laser and plasma parameters are useful in understanding the relativistic laser-plasma interactions. Here the authors extend the model of holeboring for arbitrary profiles of laser pulse and plasma scale lengths.
- J. Hornung
- , Y. Zobus
- & V. Bagnoud
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Article
| Open AccessControlled beat-wave Brillouin scattering in the ionosphere
Nonlinear wave mixing has been explored in space plasma. Here the authors report beat-wave Brillouin scattering experiment at EISCAT, in which two radio waves at different transmitted frequencies are driving ion acoustic waves in the ionosphere, leading to stimulated Brillouin emissions escaping the plasma.
- B. Eliasson
- , A. Senior
- & R. Bingham
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Article
| Open AccessSympathetic cooling of positrons to cryogenic temperatures for antihydrogen production
Positrons are key to the production of cold antihydrogen. Here the authors report the sympathetic cooling of positrons by interacting them with laser-cooled Be+ ions resulting in a three-fold reduction of the temperature of positrons for antihydrogen synthesis.
- C. J. Baker
- , W. Bertsche
- & J. S. Wurtele
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Article
| Open AccessMagnetopause ripples going against the flow form azimuthally stationary surface waves
The magnetopause surface waves (SW) that drive global plasma dynamics are thought, like waves on water, to travel with the driving solar wind. Here, the authors show that impulsively-excited SW, with standing structure along the geomagnetic field, are stationary by propagating against this flow.
- M. O. Archer
- , M. D. Hartinger
- & L. Rastaetter
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Article
| Open AccessCharge of clustered microparticles measured in spatial plasma afterglows follows the smallest enclosing sphere model
Here the authors report measurements of the charge ratio and mass of two-particle clusters and single microparticles in the spatial plasma afterglow. The insights contribute to the general understanding of non-spherical particle charging in ionized gasses.
- B. van Minderhout
- , J. C. A. van Huijstee
- & J. Beckers
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Article
| Open AccessTopological phases and bulk-edge correspondence of magnetized cold plasmas
Magnetized plasma can be regarded as topological matter. Here the authors identify a necessary and sufficient condition for the existence of topological edge mode and find that cold magnetized plasma has ten topological phases in the plasma frequency, cyclotron frequency and wave-vector space.
- Yichen Fu
- & Hong Qin
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Article
| Open AccessCollisionless relaxation of a disequilibrated current sheet and implications for bifurcated structures
Bifurcated current sheets are a recurring feature in magnetized space plasmas. Here the authors explain the emergence of bifurcated structures by natural redistributions of single-particle orbits during the collisionless relaxation process of a disequilibrated current sheet.
- Young Dae Yoon
- , Gunsu S. Yun
- & James L. Burch
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Article
| Open AccessLaboratory measurements of the physics of auroral electron acceleration by Alfvén waves
It was predicted that Alfvén waves can account for the acceleration of precipitating auroral electrons. Here, the authors show laboratory measurements of the resonant transfer of energy from Alfvén waves to electrons under conditions relevant to the auroral zone as a direct test.
- J. W. R. Schroeder
- , G. G. Howes
- & S. Dorfman