Is the Family members Amongst the Solar power Piece of cake Active Tension as well as the Magnetopause Standoff Length so Easy?

Is the Family members Amongst the Solar power Piece of cake Active Tension as well as the Magnetopause Standoff Length so Easy?

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 Realization

Brand new magnetopause is the line amongst the close-Earth place, that is governed by magnetic field produced in the Planet’s center, and interplanetary area populated of the plasma produced about Sunshine called the solar power wind. In this performs, i reexamine the partnership involving the magnetopause reputation and you joingy may parameters out-of the brand new solar power snap by means of computers modeling. It is revealed that the relationship ranging from solar power snap velocity and you may thickness and magnetopause standing is far more cutting-edge than just in the first place 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 ) compared noticed magnetopause crossings into the Shue mais aussi al. model (Shue et al., 1997 ) getting half the very last solar years and discovered logical distinctions between your design and observations. It debated that ionospheric conductivity in addition to solar snap velocity was additional details you to dictate new magnetopause condition. Their analytical research shows that the common magnetopause was further of the earth than simply predicted throughout the date times that have down conductivity and you may higher solar power piece of cake velocity. It ideal you to intensification regarding Ultraviolet radiation causes an increase about magnetospheric-ionospheric currents you to definitely decreases the magnetized stress within the magnetosphere and new magnetopause motions earthward. Quite the opposite, enhancement of the velocity intensifies the brand new viscous communication between the solar cinch and magnetosphere raising the worldwide magnetospheric convection and you can taking a great deal more magnetic flux with the dayside magnetosphere. We’ll discuss this type of assumptions below in the paper.

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