In this study we use two-loop model SCW (SCW2L) to quantitatively investigate distortion of the ionospheric footpoint pattern in response to changes of different SCW2L parameters. Calculation results show that SCW-related footprint shifts result in formation of auroral bulge and westward travelling surge and may contribute to rotation of auroral streamers, and that SCW2L combined with the AM03 model nicely describes the azimuthal progression and the observed magnitude of the auroral expansion.

A new quantitative model of the global shape of the neutral sheet in the Earth's magnetosphere is developed, parameterized by the dipole tilt, solar wind pressure, and IMF By and Bz. The model is based on data from the Polar, Cluster, Geotail, and Themis satellites taken in 1995-2013. The paper quantifies and further explains our earlier finding of the bowl-shaped deformation of the neutral sheet due to the Earth's dipole tilt (Tsyganenko and Andreeva, GRL, v.41(4), 2014).