The generation of magnetic fields by the Biermann battery and the interplay with the Weibel instability
Author(s)
Schoeffler, K. M.; Fonseca, R. A.; Silva, L. O.; Gomes Loureiro, Nuno F
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An investigation of magnetic fields generated in an expanding bubble of plasma with misaligned temperature and density gradients (driving the Biermann battery mechanism) is performed. With gradient scales L, large-scale magnetic fields are generated by the Biermann battery mechanism with plasma 1, as long as L is comparable to the ion inertial length di. For larger system sizes, L/de 100 (where deis the electron inertial length), the Weibel instability generates magnetic fields of similar magnitude but with wavenumber kde0.2. In both cases, the growth and saturation of these fields have a weak dependence on mass ratio mi/me, indicating electron mediated physics. A scan in system size is performed at mi/me= 2000, showing agreement with previous results with mi/me= 25. In addition, the instability found at large system sizes is quantitatively demonstrated to be the Weibel instability. Furthermore, magnetic and electric energy spectra at scales below the electron Larmor radius are found to exhibit power law behavior with spectral indices -16/3 and -4/3, respectively.
Date issued
2016-04Department
Massachusetts Institute of Technology. Plasma Science and Fusion CenterJournal
Physics of Plasmas
Publisher
American Institute of Physics (AIP)
Citation
Schoeffler, K. M. et al. “The Generation of Magnetic Fields by the Biermann Battery and the Interplay with the Weibel Instability.” Physics of Plasmas 23, 5 (May 2016): 056304 © 2016 Author(s)
Version: Author's final manuscript
ISSN
1070-664X
1089-7674