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Annales Geophysicae An interactive open-access journal of the European Geosciences Union
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Volume 29, issue 12
Ann. Geophys., 29, 2239–2252, 2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 29, 2239–2252, 2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.

Regular paper 10 Dec 2011

Regular paper | 10 Dec 2011

Accuracy of multi-point boundary crossing time analysis

J. Vogt1, S. Haaland2,3, and G. Paschmann4 J. Vogt et al.
  • 1School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
  • 2Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany
  • 3Department of Physics and Technology, University of Bergen, Norway
  • 4Max-Planck-Institut für extraterrestrische Physik, Garching, Germany

Abstract. Recent multi-spacecraft studies of solar wind discontinuity crossings using the timing (boundary plane triangulation) method gave boundary parameter estimates that are significantly different from those of the well-established single-spacecraft minimum variance analysis (MVA) technique. A large survey of directional discontinuities in Cluster data turned out to be particularly inconsistent in the sense that multi-point timing analyses did not identify any rotational discontinuities (RDs) whereas the MVA results of the individual spacecraft suggested that RDs form the majority of events. To make multi-spacecraft studies of discontinuity crossings more conclusive, the present report addresses the accuracy of the timing approach to boundary parameter estimation. Our error analysis is based on the reciprocal vector formalism and takes into account uncertainties both in crossing times and in the spacecraft positions. A rigorous error estimation scheme is presented for the general case of correlated crossing time errors and arbitrary spacecraft configurations. Crossing time error covariances are determined through cross correlation analyses of the residuals. The principal influence of the spacecraft array geometry on the accuracy of the timing method is illustrated using error formulas for the simplified case of mutually uncorrelated and identical errors at different spacecraft. The full error analysis procedure is demonstrated for a solar wind discontinuity as observed by the Cluster FGM instrument.

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