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 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.
Ordinary Words Realization
This new magnetopause ‘s the line between the near-Environment place, which is ruled from the magnetic community manufactured in this new Planet’s core, and interplanetary space populated of the plasma emitted on Sunrays called the solar piece of cake. Within this really works, i reexamine the connection involving the magnetopause updates and you will details out-of the latest solar power piece of cake by means of computers acting. It’s shown your matchmaking anywhere between solar power wind acceleration and you can density and you can magnetopause reputation is far more complex than originally consider.
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.
Has just, Nemecek et al. ( 2016 ) opposed noticed magnetopause crossings towards the Shue et al. design (Shue mais aussi al., 1997 ) having half wskazówki dotyczące getiton of the last solar period and discovered scientific distinctions between your model and you will observations. It contended that ionospheric conductivity plus the solar cinch speed are a lot more details you to determine the new magnetopause position. Its analytical research shows that an average magnetopause are farther out-of the planet than just forecast throughout the big date periods with all the way down conductivity and you may higher solar snap acceleration. It ideal that intensification regarding Ultraviolet radiation contributes to an increase throughout the magnetospheric-ionospheric currents that decreases the magnetic pressure inside magnetosphere and you will this new magnetopause motions earthward. On the contrary, enhancement of your own acceleration intensifies the brand new viscous interaction between the solar snap and you will magnetosphere increasing the all over the world magnetospheric convection and you will taking far more magnetized flux for the dayside magnetosphere. We will talk about these assumptions less than on the report.