Lifetime estimate for plasma turbulence
- 1Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria
- 2Institute of Physics, University of Graz, Universitätsplatz 5, 8010 Graz, Austria
- 3Institut für Geophysik und extraterrestrische Physik, Technische Universität Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- 4Geodetic and Geophysical Institute, RCAES, Hungarian Academy of Sciences, Sopron, Hungary
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.