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.
Basic Code Bottom line
The newest magnetopause is the boundary amongst the near-World place, that’s ruled from the magnetic job made in the latest Planet’s key, and interplanetary room populated because of the plasma released on Sunshine called the solar power cinch. Inside functions, we reexamine the connection amongst the magnetopause updates and you will variables regarding brand new solar power breeze by means of computer acting. It is shown that the relationships ranging from solar piece of cake velocity and density and you can magnetopause status is much more cutting-edge than simply originally imagine.
step 1 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 (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 datingranking.net/pl/fling-recenzja 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 mais aussi al. ( 2016 ) compared noticed magnetopause crossings toward Shue et al. model (Shue mais aussi al., 1997 ) having 50 % of the last solar power years and found health-related distinctions involving the design and you may findings. They argued that ionospheric conductivity additionally the solar power snap velocity was even more parameters one to determine the brand new magnetopause updates. Their statistical data shows that the average magnetopause is actually further out-of our planet than just predicted through the day durations with all the way down conductivity and you can highest solar power cinch velocity. They advised you to intensification of Uv light causes a growth regarding magnetospheric-ionospheric currents you to decreases the magnetic pressure when you look at the magnetosphere and brand new magnetopause motions earthward. On the other hand, improvement of one’s velocity intensifies the newest viscous communications within solar breeze and you can magnetosphere enhancing the around the globe magnetospheric convection and you can delivering way more magnetized flux on the dayside magnetosphere. We shall talk about this type of presumptions below about paper.