‘s the Family members Between the Solar Breeze Vibrant Pressure while the Magnetopause Standoff Length very Easy?

We present results of global magnetohydrodynamic simulations which reconsider the relationship between the solar wind dynamic pressure (P_d) and magnetopause standoff distance (R_Sub). 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.

Basic Code Summary

The brand new magnetopause is the line involving the close-Environment area, that is influenced of the magnetized industry made in the brand new World’s center, and interplanetary area populated because of the plasma produced on Sun called the solar piece of cake. Inside really works, we reexamine the relationship involving the magnetopause standing and you can variables out of the brand new solar power breeze in the form of pc acting. It is shown the relationships anywhere between solar power snap speed and thickness and you can magnetopause position is much more state-of-the-art than simply to begin with envision.

step one Addition

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 (P_d) 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) B_z component (Aubry et al., 1970 ; Fairfield, 1971 ). A strong southward IMF (B_z<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 P_d and B_z 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 mais aussi al. ( 2016 ) compared seen magnetopause crossings into the Shue ainsi que al. design (Shue mais aussi al., 1997 ) getting 1 / 2 of the very last solar power duration and found logical differences between your design and you may findings. It argued the ionospheric conductivity therefore the solar power snap speed are additional variables one to influence new magnetopause condition. Its statistical data signifies that an average magnetopause are further out of the world than simply forecast throughout time times with lower conductivity and you can large solar snap speed flirtwith. They recommended you to definitely intensification regarding Ultraviolet light contributes to a rise from the magnetospheric-ionospheric currents you to definitely reduces the magnetic tension inside the magnetosphere and you may the new magnetopause moves earthward. On the contrary, enhancement of one’s acceleration intensifies new viscous correspondence amongst the solar piece of cake and you may magnetosphere raising the in the world magnetospheric convection and you may providing alot more magnetic flux towards the dayside magnetosphere. We will explore this type of presumptions below from the report.