step 3 Dialogue and Conclusions
Most empirical magnetopause designs suppose a standard family involving the solar power cinch active pressure in addition to magnetopause standoff distance step 1, where N stays lingering for everyone solar power snap requirements. About fake works, we changes only 1 solar cinch plasma parameter, often the brand new density or velocity, having the same step-for example develops regarding vibrant tension in the two cases. I result in the simulations to have northward and you will southward IMF and you may assess the power laws list N. I examine multiple types of SWMF and LFM-Mix habits acquire comparable fashion for everybody designs just like the explained 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 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 & hater 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.
In our functions, i only use MHD simulations and work out operates into the phony solar power cinch standards. Yet not, we feel that MHD models reproduce reasonably really the fresh new magnetopause standoff range for regular solar power wind conditions (Samso ). I allowed this particular works will assist on the development of future empirical magnetopause patterns. Among imminent missions that can investigation variations of dayside magnetopause ‘s the Solar Snap Magnetosphere Ionosphere Connect Explorer (SMILE) (Raab mais aussi al., 2016 ). Having fun with Smile, we will be in a position to obtain a continuing go out selection of the latest magnetopause standoff point getting variable solar power snap criteria while having confirm possible empirical designs.
Acknowledgments
This really works is actually carried out by using the SWMF/BATSRUS gadgets create during the University out-of Michigan Cardio to possess Room Environment Modeling therefore the LFM-Blend design offered from the NASA Area Paired Acting Cardiovascular system ( Particularly, i used outcome of this new runs Andrey_Samsonov_072419_(1-4). A great. A beneficial. S. and you will G. B. R. recognize support in the United kingdom Place Department less than Give ST/R002258/1. Y. V. B. are backed by new STFC RAL Area IHR grant.