Articles | Volume 33, issue 11
ANGEO Communicates
13 Nov 2015
ANGEO Communicates |  | 13 Nov 2015

Non-elliptic wavevector anisotropy for magnetohydrodynamic turbulence

Y. Narita

Abstract. A model of non-elliptic wavevector anisotropy is developed for the inertial-range spectrum of magnetohydrodynamic turbulence and is presented in the two-dimensional wavevector domain spanning the directions parallel and perpendicular to the mean magnetic field.

The non-elliptic model is a variation of the elliptic model with different scalings along the parallel and the perpendicular components of the wavevectors to the mean magnetic field.

The non-elliptic anisotropy model reproduces the smooth transition of the power-law spectra from an index of −2 in the parallel projection with respect to the mean magnetic field to an index of −5/3 in the perpendicular projection observed in solar wind turbulence, and is as competitive as the critical balance model to explain the measured frequency spectra in the solar wind. The parameters in the non-elliptic spectrum model are compared with the solar wind observations.

Short summary
A lot of efforts have been put into understanding the turbulence structure in space and astrophysical plasmas, in particular how the filamentary structure develops as the length scale of the turbulent fluctuations changes from large to smaller ones. Motivated by the recent spacecraft observations in the solar wind, an analytic model is proposed to explain the nature of filament-formation processes in space plasma turbulence with a successful test against the spacecraft observations.