INVERSE CASCADE IN SPACE TURBULENCE DURING CURRENT DISRUPTION

etc15 Tracking Number 127

Wavelet analysis of magnetic fluctuations during space turbulence observed in current disruption events of the Earth’s magnetotail shows that energy is released at progressively lower frequency with time. This feature departs from the expectation of fluid turbulence and arises from the excitation of a kinetic instability in the Earth’s magnetotail current sheet. From insights gained from two-dimensional particle simulation of the instability, it is found that the inverse cascade phenomenon can be identified as the basic property of the excited plasma instability. It is caused by excited waves associated with the instability having slower growth rates with increasing wavelength.