step 3 Talk and you may Findings
Really empirical magnetopause designs assume a standard family amongst the solar power cinch vibrant tension as well as the magnetopause standoff point step one, where Letter remains lingering for all solar snap criteria. On phony runs, we change one solar power cinch plasma factor, either the thickness otherwise speed, acquiring the exact same action-including expands regarding the active pressure in both cases. I make simulations to possess northward and southward IMF and estimate the power legislation list N. We contrast numerous versions of one’s SWMF and you may LFM-Blend patterns and get comparable manner for everybody patterns given that 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 straightforward conclusion from these results.
Within our functions, i only use MHD simulations and also make runs for the artificial solar power snap standards. However, we believe one MHD models replicate reasonably really brand new magnetopause standoff point to own typical solar cinch requirements (Samso ). We anticipate that the performs will help from the growth of coming empirical magnetopause designs. Among forthcoming missions that may studies distinctions of one’s dayside magnetopause ‘s the Solar power Wind Magnetosphere Ionosphere Link Explorer (SMILE) (Raab mais aussi al., 2016 ). Using Laugh, i will be capable obtain a continuing big date series of brand new magnetopause standoff point to have adjustable solar breeze criteria as well as hot or not have verify prospective empirical patterns.
Acknowledgments
So it works was carried out utilizing the SWMF/BATSRUS systems set-up at the College away from Michigan Heart getting Space Environment Modeling in addition to LFM-Blend design readily available from NASA Neighborhood Matched Acting Center ( In particular, we used result of this new operates Andrey_Samsonov_072419_(1-4). An effective. A great. S. and Grams. B. Roentgen. admit support on Uk Space Service below Offer ST/R002258/1. Y. V. B. was supported by the fresh new STFC RAL Room IHR grant.