Effective field theory of force-free electrodynamics

Gralla, Samuel E.; Iqbal, Nabil

Abstract

Force-free electrodynamics (FFE) is a closed set of equations for the electromagnetic field of a magnetically dominated plasma. There are strong arguments for the existence of force-free plasmas near pulsars and active black holes, but FFE alone cannot account for the observational signatures, such as coherent radio emission and relativistic jets and winds. We reformulate FFE as the effective field theory of a cold string fluid and initiate a systematic study of corrections in a derivative expansion. At leading order the effective theory is equivalent to (generalized) FFE, with the strings comprised by magnetic field line world sheets. Higher-order corrections generically give rise to nonzero accelerating electric fields (E⋅B≠0). We discuss potential observable consequences and comment on an intriguing numerical coincidence.

Citation

Gralla, S. E., & Iqbal, N. (2019). Effective field theory of force-free electrodynamics. Physical Review D, 99(10), Article 105004. https://doi.org/10.1103/physrevd.99.105004

• Journal Article Type: Article
• Acceptance Date: Mar 27, 2019
• Online Publication Date: May 14, 2019
• Publication Date: Apr 30, 2019
• Deposit Date: May 15, 2019
• Publicly Available Date: May 17, 2019
• Journal: Physical Review D
• Print ISSN: 2470-0010
• Electronic ISSN: 2470-0029
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 99
• Issue: 10
• Article Number: 105004
• DOI: https://doi.org/10.1103/physrevd.99.105004
• Public URL: https://durham-repository.worktribe.com/output/1301579
• Related Public URLs: https://arxiv.org/abs/1811.07438