It is well known that the plasmapause is influenced by the solar wind and magnetospheric conditions. Empirical models of its location have been previously developed such as those by O'Brien and Moldwin (2003) and Larsen et al. (2006). In this study, we identified the locations of the plasmapause using the plasma density data obtained from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites. We used the data for the period (2008–2012) corresponding to the ascending phase of Solar Cycle 24. Our database includes data from over a year of unusually weak solar wind conditions, correspondingly covering the plasmapause locations in a wider L range than those in previous studies. It also contains many coronal hole stream intervals during which the plasmasphere is eroded and recovers over a timescale of several days. The plasmapause was rigorously determined by requiring a density gradient by a factor of 15 within a radial distance of 0.5 L. We first determined the statistical correlation of the plasmapause locations with several solar wind parameters as well as geomagnetic indices. We found that the plasmapause locations are well correlated with the solar wind speed and the interplanetary magnetic field Bz, therefore the y component of the convective electric field, and some energy coupling functions such as the well‐known Akasofu's epsilon parameter. The plasmapause locations are also highly correlated with the geomagnetic indices, Dst, AE, and Kp, as recognized previously. Finally, we suggest new model fit functions for the plasmapause locations in terms of the solar wind parameters and geomagnetic indices. When applied to a new data interval outside the model training interval, our model fit functions work better than existing ones. The new model fit functions developed here extend the range of conditions from those used in previous works.

We perform a statistical comparison of the global behavior of the THEMIS observed and simulated plasmapause in the geomagnetic equatorial plane. Simulation is based on the interchange instability mechanism. Analyzing plasmapause positions (LPPs) from the period July 2008 to December 2012, we derived formation and propagation characteristics of the main plasmapause, which reflect the most probable global plasmapause behavior. The results suggest a global eastward azimuthal plasmapause propagation and a radial plasmapause motion limited to the 21–07 MLT sector. The formation of the plasmapause takes place with the highest probability at postmidnight. It is likely that the erosion occurs in a range of MLTs simultaneously. On the dayside, the plasmapause moves almost entirely azimuthally. We suggest that the plasmapause propagates azimuthally with a mean angular velocity close to the corotation speed at all MLTs, at least during periods of lower geomagnetic activity. The results also show that the experimental plasmapause characteristics are in accordance with the interchange instability mechanism. Along with the proposed suggestions for future works, this study contributes to making a further step toward resolving some of the long‐lasting, unresolved issues related to plasmapause dynamics.

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