skip to main content

DOE PAGESDOE PAGES

Title: Magnetic field production via the Weibel instability in interpenetrating plasma flows

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 themore » microphysics present in the collisional–collisionless transition.« less
Authors:
ORCiD logo [1] ;  [2] ;  [1] ;  [1] ;  [3] ; ORCiD logo [1] ;  [1] ;  [4] ; ORCiD logo [1] ;  [5] ;  [1] ; ORCiD logo [1] ;  [1] ;  [3] ; ORCiD logo [6] ;  [7] ;  [5] ; ORCiD logo [1] ; ORCiD logo [6] ; ORCiD logo [8]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Univ. of Michigan, Ann Arbor, MI (United States)
  3. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  4. Univ. of Oxford, Oxford (United Kingdom)
  5. Princeton Univ., Princeton, NJ (United States)
  6. Osaka Univ., Osaka (Japan)
  7. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  8. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
LLNL-PROC-717204
Journal ID: ISSN 1070-664X; PHPAEN
Grant/Contract Number:
AC52-07NA27344; 15-ERD-065
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 4; Conference: High Energy Density Laboratory Astrophysics, Palo Alto, CA (United States), 16-21 May 2016; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; 70 PLASMA PHYSICS AND FUSION
OSTI Identifier:
1357407
Alternate Identifier(s):
OSTI ID: 1361845