Magnetic helicity and the evolution of decaying magnetohydrodynamic turbulence

Arjun Berera*, Moritz Linkmann

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Ensemble-averaged high resolution direct numerical simulations of reverse spectral transfer are presented, extending on the many single realization numerical studies done up to now. This identifies this type of spectral transfer as a statistical property of magnetohydrodynamic turbulence and thus permits reliable numerical exploration of its dynamics. The magnetic energy decay exponent from these ensemble runs has been determined to be nE=(0.47±0.03)+(13.9±0.8)/Rλ for initially helical magnetic fields. We show that even after removing the Lorentz force term in the momentum equation, thus decoupling it from the induction equation, reverse spectral transfer still persists. The induction equation is now linear with an externally imposed velocity field, thus amenable to numerous analysis techniques. A new door has opened for analyzing reverse spectral transfer, with various ideas discussed.

Original languageEnglish
Article number041003
JournalPhysical Review E - Statistical, Nonlinear and Soft Matter Physics
Issue number4
Publication statusPublished - 22 Oct 2014

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