I make a few MHD works to check on which expectation
3 Conversation and you will Results
Very empirical magnetopause patterns assume a general relation amongst the solar power snap dynamic pressure while the magnetopause standoff range step 1, in which N stays ongoing for all solar power snap criteria. From the artificial operates, i transform only one solar wind plasma factor, sometimes the fresh new occurrence or speed, getting the exact same action-for example develops regarding dynamic stress in the two cases. We result in the simulations to own northward and southward IMF and you can estimate the advantage laws index N. I contrast several brands of your SWMF and you may LFM-Combine designs and obtain comparable fashion for everyone activities once the explained lower than.
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 https://datingranking.net/pl/gleeden-recenzja/ 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 RSandwich by the Shue et al. ( 1997 ) model and obtained that the model underestimates RSub 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 straightforward conclusion from these results.
Within functions, we use only MHD simulations and also make runs towards phony solar breeze criteria. However, we feel that MHD designs reproduce reasonably really this new magnetopause standoff point to own regular solar power cinch standards (Samso ). I allowed this particular functions will help regarding growth of coming empirical magnetopause habits. Among the certain missions that may studies differences of your own dayside magnetopause is the Solar power Snap Magnetosphere Ionosphere Connect Explorer (SMILE) (Raab ainsi que al., 2016 ). Using Smile, i will be able to receive a continuing go out variety of the new magnetopause standoff range getting varying solar power wind standards and then have verify possible empirical models.
Acknowledgments
That it performs are achieved utilizing the SWMF/BATSRUS gadgets setup at the College or university regarding Michigan Heart getting Room Ecosystem Acting and LFM-Blend design offered through the NASA Community Coordinated Acting Cardiovascular system ( Particularly, we utilized outcome of brand new operates Andrey_Samsonov_072419_(1-4). A good. A. S. and you will Grams. B. R. admit service on Uk Area Institution not as much as Offer ST/R002258/step 1. Y. V. B. was backed by new STFC RAL Space IHR grant.