Using seemingly small (20 minute) day durations amongst the active pressure measures, we implicitly think that the alterations regarding the magnetopause condition primarily originate from the changes in the solar power piece of cake tension and you may variations of one’s dayside career-lined up Part 1 currents. Whilst magnetotail latest could have a slightly big impulse day, in general they just intensifies the result of Part step one latest. grams., certain estimations were made when you look at the Samso ); but not, (1) the new noncoupled MHD design hence results was indeed presented a lot more than does perhaps not reproduce new ring current and you can (2) the time scale of your ring current intensification is oftentimes more as compared to step 3–cuatro time utilized in these types of simulations. We show results of one’s combined models lower than that is qualitatively just as the outcome of the newest noncoupled design, which means this does not change our very own findings.
In the end, we want to evaluate numerous runs to confirm which our results are model-independent. Table 1 collects the power legislation indicator N inside the (1) calculated of half dozen items away from around three around the globe MHD designs. The first is this new noncoupled SWMF model whoever results was basically exhibited significantly more than. In addition to the first operates (Variation step one), i simulated about three other types of one’s a comparable noncoupled design, a couple with increased ionospheric conductivity and something that have a beneficial dipole tilt. The newest top-provided Pedersen conductivity is assumed to-be comparable to 5 S throughout brand new designs, but designs dos and you will step 3 which the fresh included conductivity are 10 and one hundred S correspondingly. For the version cuatro, i artificial the brand new magnetosphere having good dipole tilt 29° . Alterations in N between Models step one and you may 2 and you may Types step one and you may 4 are small, and you will anywhere between Types step one and you may 3 try moderate, however, simply for the brand new southward IMF. Remember that this new ionospheric conductivity a hundred S may be very highest and you can should be hardly seen in reality. I inform you they merely to instruct the new part of conductivity as the 2 minutes boost in conductivity during the Type dos changes Letter just for new acceleration raise having southward IMF.
An increase in brand new magnetotail current as well upsurge in this new Part step one currents weakens the magnetospheric magnetized industry and you will motions new dayside magnetopause earthward
Adaptation 5 means works of your own SWMF design coupled with full interior-magnetosphere ionosphere, and you will Type 6 is the LFM-Combine design. Per type, i build four runs with the northward/southward IMF and also for the occurrence and you may acceleration develops as the explained more than (twenty-four works in total). Bear in mind one N=six on the better theoretic instance should your magnetopause position suits the stress equilibrium between the solar power piece of cake vibrant pressure and Planet’s dipole career and N=six.six from the empirical Shue mais aussi al. ( 1998 ) model. Actually, all of the acquired Letter was anywhere between these two viewpoints or somewhat less. Five away from six systems expect N big or comparable to 7 regarding the operates for the thickness increase to own southward IMF. Regardless of if Variation 5 forecasts N smaller compared to 7, N was systematically large in this situation each design.
Meanwhile, Tsyganenko and Sibeck ( 1994 ) listed the mix-tail most recent and in a less studies the newest ring most recent and the spot step 1 currents influence the latest magnetic industry into the magnetospheric side of the magnetopause
In addition to the comparison of different models, we investigate the influence of grid resolution on our results. We have calculated two runs for the same southward IMF with density and velocity changes using the noncoupled SWMF model with the 1/16 RE grid spacing around the subsolar magnetopause. We obtain different power laws, N=6.712 and 6.132, in the density and velocity runs, respectively (instead of 7.80 and 6.69 for the same model with a low resolution). Moreover, the normalized (to the solar wind electric field) reconnection rates in the low-resolution runs are smaller than those in the high-resolution runs (but are about the same in the density and velocity runs for the same resolution). We also find some differences in the CPCP and the magnetic field magnitude at geosynchronous orbit. We note that the grid resolution influences the magnitude of maximal electric current density at the magnetopause and possibly may change the total magnetopause current, but this problem requires more careful studies and it stays outside of the scope of the paper.