Quantitatively estimating magnetotail flapping motion is critical to
understanding and characterizing the dynamics of flapping behaviors.
Such an estimation could be achieved in principle by the multipoint
analysis of spacecraft tetrahedron, e.g. Cluster or MMS mission, but,
owing to the inability of single-point measurement to separate the
spatial-temporal variation of magnetic field, would be inadequate for a
spacecraft. Since single-point missions dominate explorations of
planetary magnetotail, we have developed a single-point method based on
the magnetic field measurement that quantitatively estimates the
parameters of flapping motion, including spatial amplitude, wavelength,
and propagation velocity. A comparison with the application of
multi-point analysis of Cluster demonstrates that our method can be
reasonably be applied to infer the average parameters over a flapping
period. Thus, this method could be applied widely to the “big dataset”
accumulated by single-point spacecraft missions in order to study
magnetotail flapping dynamics.