118 research outputs found
Role of Cross Helicity in Cascade Processes of MHD turbulence
The purpose of this work is to investigate the spectral properties of the
developed isotropic (non-Alfven) MHD turbulence stationary excited by an
external force, which injects the cross helicity into the flow simultaneously
with the energy. It is shown that the cross helicity blocks the spectral energy
transfer in MHD turbulence and results in energy accumulation in the system.
This accumulation proceeds until the vortex intensification compensates the
decreasing efficiency of nonlinear interactions. The formula for estimating the
average turbulence energy is obtained for the set ratio between the injected
helicity and energy. It is remarkable that the turbulence accumulates the
injected cross helicity at its low rate injection -- the integral correlation
coefficient significantly exceeds the ratio between the injected helicity and
the energy. It is shown that the spectrum slope gradually increases from "5/3"
to "2" with the cross helicity level.Comment: 4 page
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