3 Conversation and Results
Very empirical magnetopause habits assume an over-all family relations between the solar snap vibrant tension as well as the magnetopause standoff range step 1, where Letter stays constant for everybody solar power piece of cake conditions. About artificial runs, we transform just one solar power piece of cake plasma parameter, both the thickness otherwise velocity, getting the same step-instance increases on active stress in the two cases. I result in the simulations for northward and you can southward IMF and you will determine the benefit law index N. We compare numerous products of one’s SWMF and you will LFM-Combine patterns acquire similar styles for everybody designs because said below.
Our results also show that the increase in the ionospheric conductivity or the use of a model with the additional inner magnetosphere-ionosphere block result in decrease in N. Therefore, we cannot derive a single N from the MHD simulations because the dispersion in N between the models is large; however, all models predict the same changes between different runs related to the density and velocity increases, and Bz sign.
The simulations we present suggest that dayside magnetopause reconnection influences the magnetic field magnitude at geosynchronous orbit near subsolar point. We obtain different geosynchronous magnetic fields in northward and southward IMF runs with the same dynamic pressure. Moreover, the magnetic field magnitude is also different when comparing the runs in which both the dynamic pressure and Bz are kept the same and only the ratio between the solar wind ? and V is different. Increasing velocity instead of density for a southward IMF, we increase the magnetopause reconnection rate and this results in an observable difference in the magnetic field at geosynchronous orbit with a smaller |B| corresponding to a larger VSW. Similar variations at geosynchronous orbit are observed in northward/southward turning events with a constant solar wind dynamic pressure (Samso ).
Our results partly agree with the results in Nemecek et al. ( 2016 ). We find that an increase in the ionospheric conductivity causes stronger variations of the magnetopause standoff distance, but, contrary to Nemecek et al. ( 2016 ), an increase in the solar wind velocity may also enhance variations of the standoff distance. However, we cannot compare our results with Nemecek et al. ( 2016 ) directly. Nemecek et al. ( 2016 ) normalized observed RSub by the Shue et al. ( 1997 ) model and obtained that the model underestimates RSandwich for high velocities. First, we note that it would agree with a numerical model for which N>6.6 since N=6.6 in Shue et al. ( 1997 ). Second, variations of the solar wind velocity cannot be treated independently in the observations, they correlate with variations of the magnetic field (Owens & Cargill, 2002 ), and even (on a large time scale) with the ionospheric conductivity because higher velocities are usually observed at solar maximum. Therefore, it is difficult to make a quizy grindr straightforward conclusion from these results.
Inside our works, we use only MHD simulations while making runs into phony solar snap requirements. But not, we believe you to definitely MHD models duplicate relatively better the brand new magnetopause standoff range getting normal solar piece of cake conditions (Samso ). We welcome that this works can assist regarding the development of coming empirical magnetopause habits. One of the impending missions that may analysis distinctions of dayside magnetopause is the Solar Cinch Magnetosphere Ionosphere Hook up Explorer (SMILE) (Raab ainsi que al., 2016 ). Having fun with Laugh, i will be capable receive an ongoing go out variety of the latest magnetopause standoff range getting changeable solar wind conditions and then have confirm possible empirical activities.
Acknowledgments
Which work try accomplished with the SWMF/BATSRUS systems build on College or university out of Michigan Heart to have Place Ecosystem Modeling plus the LFM-Combine model offered through the NASA People Matched Acting Heart ( In particular, i put outcome of new works Andrey_Samsonov_072419_(1-4). A good. A. S. and you may G. B. Roentgen. recognize service on the United kingdom Space Service less than Grant ST/R002258/1. Y. V. B. is actually supported by the new STFC RAL Room IHR give.
