We present results of global magnetohydrodynamic simulations which reconsider the relationship between the solar wind dynamic pressure (Pd) and magnetopause standoff distance (RSub). We simulate the magnetospheric response to increases in the dynamic pressure by varying separately the solar wind density or velocity for northward and southward interplanetary randki good grief magnetic field (IMF). We obtain different values of the power law indices N in the relation depending on which parameter, density, or velocity, has been varied and for which IMF orientation. The changes in the standoff distance are smaller (higher N) for a density increase for southward IMF and greater (smaller N) for a velocity increase.
Simple Language Conclusion
The latest magnetopause ‘s the line involving the close-Environment space, that is ruled because of the magnetized career made in new Earth’s key, and interplanetary place populated by the plasma released on Sun known as solar breeze. Within functions, we reexamine the connection within magnetopause standing and you will parameters of the newest solar power piece of cake in the shape of computer modeling. It’s found your relationship anywhere between solar wind velocity and occurrence and you may magnetopause status is far more complex than in the first place think.
step one Inclusion
The magnetopause is one of principal magnetospheric boundaries which separates dense solar wind plasma in the magnetosheath and tenuous and hot magnetospheric plasma. In response to strong solar wind pressure pulses, the magnetopause comes closer to the Earth and geosynchronous spacecraft may exit the magnetosphere and cross the magnetosheath in the subsolar region or even enter into the supersonic solar wind. To date, more than 15 empirical models of the magnetopause have been developed based on a great number of magnetopause crossings under different solar wind conditions (a list of 14 models published by Suvorova & Dmitriev, 2015 ). Chapman and Ferraro ( 1931 ) suggested that the magnetopause location can be determined from the pressure balance condition between the solar wind dynamic pressure (Pd) and the magnetic pressure of the Earth’s dipole. Besides the dynamic pressure, the second important solar wind parameter influencing the magnetopause position is the interplanetary magnetic field (IMF) Bz component (Aubry et al., 1970 ; Fairfield, 1971 ). A strong southward IMF (Bz<0) results in magnetic reconnection at the dayside magnetopause and intensification of the large-scale field-aligned (Region 1) currents connecting the magnetosphere and ionosphere and moving the magnetopause closer to the Earth (Hill & Rassbach, 1975 ; Sibeck, 1994 ). The Pd and Bz are the only two input parameters in several popular magnetopause models (e.g., Petrinec & Russell, 1996 ; Roelof & Sibeck, 1993 ; Shue et al., 1997 ; 1998 ; Sibeck et al., 1991 ). The recent (Lin et al., 2010 ) empirical model replaces the solar wind dynamic pressure by the sum of dynamic and magnetic pressures and takes into account the Earth’s dipole tilt. Moreover, several papers (Dusik et al., 2010 ; Grygorov et al., 2017 ; Merka et al., 2003 ; Samso ) note that the magnetopause significantly expands during radial IMF intervals concluding that the IMF cone angle (the angle between IMF and the Sun-Earth line) eter for calculation of the magnetopause location.
Has just, Nemecek et al. ( 2016 ) compared observed magnetopause crossings to your Shue et al. model (Shue et al., 1997 ) for half the very last solar period and found scientific variations amongst the model and you will findings. They contended that ionospheric conductivity together with solar power cinch velocity try a lot more variables you to influence the fresh magnetopause standing. The analytical analysis implies that the typical magnetopause is actually farther away from our planet than just predicted while in the time periods with lower conductivity and you can highest solar power cinch speed. They suggested one to intensification from Uv light results in a rise regarding magnetospheric-ionospheric currents one to reduces the magnetized stress inside magnetosphere and you can new magnetopause moves earthward. Quite the opposite, improvement of speed intensifies new viscous communications within solar piece of cake and you may magnetosphere raising the worldwide magnetospheric convection and you will getting far more magnetized flux on the dayside magnetosphere. We shall speak about this type of presumptions less than on the report.