Articles | Volume 24, issue 4
Special issue:
Research article
27 Oct 2017
Research article |  | 27 Oct 2017

Lifetime estimate for plasma turbulence

Yasuhito Narita and Zoltán Vörös

Abstract. A method is proposed to experimentally determine the intrinsic timescale or a decay rate of turbulent fluctuations. The method is based on the assumption that the Breit–Wigner spectrum model with a non-Gaussian frequency broadening is valid in the data analysis. The decay rate estimate is applied to the multispacecraft magnetic field data in interplanetary space, yielding the decay rate on spatial scales of about 1000 km (about 10 times larger than the ion inertial length), which is higher than the theoretical predictions from the random sweeping timescale of the eddy turnover time. The faster decay of fluctuation components in interplanetary space is interpreted as a realization of plasma physical (and not fluid mechanical) processes.

Short summary
A method is proposed to determine the temporal decay rate of turbulent fluctuations, and is applied to four-point magnetic field data in interplanetary space. The measured decay, interpreted as the energy transfer rate in turbulence, is larger than the theoretical estimate from the fluid turbulence theory. The faster decay represents one of the differences in turbulent processes between fluid and plasma media.