von Kármán-Howarth equation for three-dimensional two-fluid plasmas

ANDRÉS NAHUEL; PABLO MININNI; PABLO DMITRUK; DANIEL O. GOMEZ

PHYSICAL REVIEW E - STATISTICAL PHYSICS, PLASMAS, FLUIDS AND RELATED INTERDISCIPLINARY TOPICS

American Physics Society

Año: 2016 vol. 93 p. 1 - 7

1063-651X

We derive the von Kármán?Howarth equation for a full three-dimensional incompressible two-fluid plasma. In the long-time limit and for very large Reynolds numbers we obtain the equivalent of the hydrodynamic ?four-fifths? law. This exact law predicts the scaling of the third-order two-point correlation functions, and puts a strong constraint on the plasma turbulent dynamics. Finally, we derive a simple expression for the 4/5 law in terms of third-order structure functions, which is appropriate for comparison with in situ measurements in the solar wind at different spatial ranges.