Articles | Volume 31, issue 11
Ann. Geophys., 31, 2063–2075, 2013
Ann. Geophys., 31, 2063–2075, 2013

Regular paper 22 Nov 2013

Regular paper | 22 Nov 2013

Characteristics of the Taylor microscale in the solar wind/foreshock: magnetic field and electron velocity measurements

C. Gurgiolo1, M. L. Goldstein2, W. H. Matthaeus3, A. Viñas2, and A. N. Fazakerley4 C. Gurgiolo et al.
  • 1Bitterroot Basic Research, Hamilton, MT, USA
  • 2Heliospheric Physics Laboratory, Code 672, NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • 3Bartol Research Foundation, University of Delaware, Newark, DE, USA
  • 4Mullard Space Science Laboratory, University College London, Holmbury St. Mary Dorking, Surrey RH5 6NT, UK

Abstract. The Taylor microscale is one of the fundamental turbulence scales. Not easily estimated in the interplanetary medium employing single spacecraft data, it has generally been studied through two point correlations. In this paper we present an alternative, albeit mathematically equivalent, method for estimating the Taylor microscale (λT). We make two independent determinations employing multi-spacecraft data sets from the Cluster mission, one using magnetic field data and a second using electron velocity data. Our results using the magnetic field data set yields a scale length of 1538 ± 550 km, slightly less than, but within the same range as, values found in previous magnetic-field-based studies. During time periods where both magnetic field and electron velocity data can be used, the two values can be compared. Relative comparisons show λT computed from the velocity is often significantly smaller than that from the magnetic field data. Due to a lack of events where both measurements are available, the absolute λT based on the electron fluid velocity is not able to be determined.