1 / 13

Nonhelical inverse transfer of a decaying turbulent magnetic field

Investigating the nonhelical inverse transfer of decaying turbulent magnetic fields in the early universe, comparing helical and nonhelical aspects through rescaled equations. Discussing implications on energy-momentum tensor, with Axel Brandenburg and collaborators. The study explores weak and strong turbulence phenomena.

Download Presentation

Nonhelical inverse transfer of a decaying turbulent magnetic field

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Nonhelicalinversetransfer of a decayingturbulentmagneticfield Cosmological magnetic fields Turbulent decay Nonuniversality of MHD Weak and strong turbulence Helical, nonhelical, hydro Axel Brandenburg (Nordita  CU Boulder) with T. Kahniashvili and A. Tevzadze PRL 114, 075001 (2015)

  2. Motivation Early universe Energy momentum tensor Conformal time, rescaled equations

  3. Helical vs nonhelical 3-D decay helical vs nonhelical Initial slope E~k4 Christensson et al. (2001, PRE 64, 056405)

  4. Helical decay law:Biskamp & Müller (1999)

  5. BKT1

  6. Weak MHD turbulence, because B strong Lee, Brachet, Pouquet, Mininni, Rosenberg (2010)

  7. Inverse transfer similar to helical MHD Nonhelical gain ½ of helical case Gain from SS B Mediated by LS u Kinetic gain From B field

  8. Scaling relations

  9. Does initial spectrum determine decay?

  10. Rescaled spectra: self-similar Alternative interpretation of Olesen’s scaling relation Christensson et al. (2001, PRE 64, 056405) Initial slope E~k4

  11. Revised interpretation with integral scale x and q determined by physics from dimensional arguments

  12. Scaling relations

  13. Conclusions • Helicity slows down decay • Large scale energy increases • Nonhelical inverse transfer • Revised interpretation to Olesen • Self-similar spectra • Confirmed now by others (Berera & Linkmann 2015 Zrake 2015)

More Related