ИСТИНА

We know that under the low-pressure magnetosheath mode (LPM), associated with quasi-radial IMF, the global expansions of the magnetosphere occurs. During LPM, the dayside magnetopause can move more than 3 Re far beyond its expected equilibrium position [Suvorova et al., 2010]. However, we don't know how far the magnetopause moves and how low the magnetosheath pressure can drop during LPM. Here we report Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations of the magnetosphere at ~16.9 Re in the subsolar region. This distance corresponds to ~4.5 Re expansion of the magnetopause. Thus, the minimum value for the total pressure in the magnetosheath adjacent to the subsolar magnetopause can be estimated. The fraction of solar wind pressure applied to the magnetopause was about k=0.16 that supports very well the results reported by Suvorova’s et al. [2010]. Reference Suvorova, A. V., et al., (2010), Magnetopause expansions for quasi‐radial interplanetary magnetic field: THEMIS and Geotail observations, J. Geophys. Res., 115, A10216, doi:10.1029/2010JA015404.