Having fun with seemingly quick (20 minute) go out durations within vibrant tension methods, i implicitly think that the alterations regarding magnetopause standing mostly result from the changes regarding the solar breeze pressure and you will differences of one’s dayside career-aimed Part step 1 currents. While the magnetotail current might have a somewhat large reaction date, but in general it just intensifies the effect of one’s Area 1 newest. grams., particular estimations have been made inside the Samso ); yet not, (1) this new noncoupled MHD design and that overall performance was presented significantly more than does maybe not reproduce the fresh ring current and you will (2) the period of band newest intensification can often be a whole lot more versus step three–4 hr included in this type of simulations. We show results of your own combined patterns below that’s qualitatively just as the consequence of the new noncoupled model, so this cannot alter our conclusions.
In the end, we should examine multiple operates to verify which our email address details are model-separate. Table step one accumulates the benefit laws indicator Letter in (1) computed away from six brands regarding around three international MHD designs. The first is brand new noncoupled SWMF design whose results was indeed exhibited significantly more than. Also the earliest operates (Variation step 1), i artificial three other versions of the same noncoupled design, a couple which have a top ionospheric conductivity and another which have a dipole tip. The brand new peak-provided Pedersen conductivity is believed to-be equivalent to 5 S in most the models, but brands dos and you can 3 by which the newest included conductivity is ten and you may a hundred S correspondingly. Into the adaptation 4, we simulated brand new magnetosphere with a good dipole tip 30° . Changes in Letter ranging from Products 1 and you can 2 and you can Items 1 and 4 is actually small, and you will ranging from Items step 1 and you will step three is modest, however, simply for this new southward IMF. Note that new ionospheric conductivity one hundred S is quite higher and you can would be rarely found in reality. We let you know they simply to illustrate the fresh role regarding conductivity once the the 2 moments increase in conductivity into the Adaptation 2 change Letter simply for the brand new acceleration improve which have southward IMF.
An increase in the magnetotail newest also rise in the latest Part step one currents weakens the new magnetospheric magnetized occupation and you will moves this new dayside magnetopause earthward
Version 5 represents operates of one’s SWMF design combined with total interior-magnetosphere ionosphere, and you may Version 6 is the LFM-Merge model. Per version, we generate four runs to the northward/southward IMF and also for the occurrence and you will acceleration increases since the explained above (twenty four works as a whole). Bear in mind that N=six on the most readily useful theoretical instance if your magnetopause condition match pressure equilibrium between your solar breeze vibrant pressure in addition to Planet’s dipole community and you will Letter=6.6 in the empirical Shue et al. ( 1998 ) model. In reality, every received N is between both of these values or some smaller. Four away from six brands predict Letter big or equal to seven in the operates towards the thickness boost for southward IMF. Even when Version 5 predicts Letter smaller compared to 7, Letter are systematically higher in this situation for each and every design.
Meanwhile, Tsyganenko and you can Sibeck ( 1994 ) listed the get across-end most recent and also in a smaller education the fresh new band latest as well as the region step one currents determine the new magnetized job 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.