We present results of global magnetohydrodynamic simulations which reconsider the relationship between the solar wind dynamic pressure (Pd) and magnetopause standoff distance (RSandwich). 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 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.
Plain Words Summary
New magnetopause is the border amongst the near-Environment space, which is influenced by the magnetic field manufactured in the latest Planet’s core, and witryna mobilna instabang interplanetary area populated from the plasma released in the Sunrays called the solar power snap. Contained in this works, we reexamine the partnership amongst the magnetopause position and you can parameters out-of the brand new solar power piece of cake as computer modeling. It’s found that the relationship ranging from solar power piece of cake velocity and you may occurrence and you can magnetopause updates is more cutting-edge than simply to start with envision.
1 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.
Recently, Nemecek ainsi que al. ( 2016 ) opposed observed magnetopause crossings to your Shue et al. design (Shue mais aussi al., 1997 ) to own half the very last solar years and found medical differences involving the design and observations. They contended that the ionospheric conductivity and the solar snap speed was additional variables you to definitely influence this new magnetopause position. Its mathematical research signifies that an average magnetopause is actually further from our planet than just predicted through the day times having all the way down conductivity and high solar power wind acceleration. They suggested you to intensification regarding Ultraviolet light contributes to an increase in the magnetospheric-ionospheric currents you to reduces the magnetized stress into the magnetosphere and you may the new magnetopause actions earthward. Quite the opposite, enhancement of your velocity intensifies the fresh viscous telecommunications between the solar power cinch and you will magnetosphere increasing the international magnetospheric convection and you will getting significantly more magnetized flux for the dayside magnetosphere. We’re going to talk about this type of assumptions lower than on paper.
