We present the first laboratory generation of high-Mach-number magnetized collisionless shocks created through the interaction of an expanding laser-driven plasma with a magnetized ambient plasma. Time-resolved, two-dimensional imaging of plasma density and magnetic fields shows the formation and evolution of a supercritical shock propagating at magnetosonic Mach number M_{ms}≈12. Particle-in-cell simulations constrained by experimental data further detail the shock formation and separate dynamics of the multi-ion-species ambient plasma. The results show that the shocks form on time scales as fast as one gyroperiod, aided by the efficient coupling of energy, and the generation of a magnetic barrier between the piston and ambient ions. The development of this experimental platform complements present remote sensing and spacecraft observations, and opens the way for controlled laboratory investigations of high-Mach number collisionless shocks, including the mechanisms and efficiency of particle acceleration.
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http://dx.doi.org/10.1103/PhysRevLett.119.025001 | DOI Listing |
Nat Commun
January 2025
Southwest Research Institute, San Antonio, TX, USA.
Collisionless shock waves, found in supernova remnants, interstellar, stellar, and planetary environments, and laboratories, are one of nature's most powerful particle accelerators. This study combines in situ satellite measurements with recent theoretical developments to establish a reinforced shock acceleration model for relativistic electrons. Our model incorporates transient structures, wave-particle interactions, and variable stellar wind conditions, operating collectively in a multiscale set of processes.
View Article and Find Full Text PDFSpace Sci Rev
December 2024
Space Research Institute, Austrian Academy of Sciences, Schmiedlstraße 6, Graz, 8042 Austria.
Plasma flows with enhanced dynamic pressure, known as magnetosheath jets, are often found downstream of collisionless shocks. As they propagate through the magnetosheath, they interact with the surrounding plasma, shaping its properties, and potentially becoming geoeffective upon reaching the magnetopause. In recent years (since 2016), new research has produced vital results that have significantly enhanced our understanding on many aspects of jets.
View Article and Find Full Text PDFPhys Rev E
November 2024
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Collisionless shocks are ubiquitous in space and astrophysical plasmas, and they are essential dynamical features of these systems. Lacking Coulomb collisions, these shocks are mediated by the anomalous dissipation provided by nonlinear plasma instabilities. By numerically resolving the structure of a steady-state, ion gyroviscous shock, we show that ion gyroviscosity, alone, can produce weak (M≲1.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
Swedish Institute of Space Physics, Box 537, 75121, Uppsala, Sweden and Swedish Defence Research Agency, 16490, Stockholm, Sweden.
We use multispacecraft Magnetospheric Multiscale observations to investigate electric fields and ion reflection at a nonstationary collisionless perpendicular plasma shock. We identify subproton scale (5-10 electron inertial lengths) large-amplitude normal electric fields, balanced by the Hall term (J×B/ne), as a transient feature of the shock ramp related to nonstationarity (rippling). The associated electrostatic potential, comparable to the energy of the incident solar wind protons, decelerates incident ions and reflects a significant fraction of protons, resulting in more efficient shock-drift acceleration than a stationary planar shock.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
An experimental investigation of collisionless shock ion acceleration is presented using a multicomponent plasma and a high-intensity picosecond duration laser pulse. Protons are the only accelerated ions when a near-critical-density plasma is driven by a laser with a modest normalized vector potential. The results of particle-in-cell simulations imply that collisionless shock may accelerate protons alone selectively, which can be an important tool for understanding the physics of inaccessible collisionless shocks in space and astrophysical plasma.
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