Magnetic field production via the Weibel instability in interpenetrating plasma flows
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Univ. of Michigan, Ann Arbor, MI (United States)
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Univ. of Oxford, Oxford (United Kingdom)
- Princeton Univ., Princeton, NJ (United States)
- Osaka Univ., Osaka (Japan)
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Here, many astrophysical systems are effectively “collisionless,” that is, the mean free path for collisions between particles is much longer than the size of the system. The absence of particle collisions does not preclude shock formation, however, as shocks can be the result of plasma instabilities that generate and amplify electromagnetic fields. The magnetic fields required for shock formation may either be initially present, for example, in supernova remnants or young galaxies, or they may be self-generated in systems such as gamma-ray bursts (GRBs). In the case of GRB outflows, the Weibel instability is a candidate mechanism for the generation of sufficiently strong magnetic fields to produce shocks. In experiments on the OMEGA Laser, we have demonstrated a quasi-collisionless system that is optimized for the study of the non-linear phase of Weibel instability growth. Using a proton probe to directly image electromagnetic fields, we measure Weibel-generated magnetic fields that grow in opposing, initially unmagnetized plasma flows. The collisionality of the system is determined from coherent Thomson scattering measurements, and the data are compared to similar measurements of a fully collisionless system. The strong, persistent Weibel growth observed here serves as a diagnostic for exploring large-scale magnetic field amplification and the microphysics present in the collisional–collisionless transition.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC52-07NA27344; 15-ERD-065
- OSTI ID:
- 1357407
- Alternate ID(s):
- OSTI ID: 1361845
- Report Number(s):
- LLNL-PROC-717204; PHPAEN
- Journal Information:
- Physics of Plasmas, Vol. 24, Issue 4; Conference: High Energy Density Laboratory Astrophysics, Palo Alto, CA (United States), 16-21 May 2016; ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Steady-State Electrostatic Layers From Weibel Instability in Relativistic Collisionless Shocks
Transition from Collisional to Collisionless Regimes in Interpenetrating Plasma Flows on the National Ignition Facility