‘s the Relation Between the Solar power Piece of cake Dynamic Stress and also the Magnetopause Standoff Length therefore Quick?

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.

Plain Vocabulary Realization

The magnetopause is the border between your near-World space, that is influenced by the magnetized job manufactured in the newest Planet’s core, and you may interplanetary place populated because of the plasma produced regarding Sun called the solar power breeze. Within really works, we reexamine the partnership amongst the magnetopause status and you may variables from the newest solar power piece of cake in the shape of desktop acting. It is shown your matchmaking anywhere between solar power wind velocity and you will density and you can magnetopause status is more cutting-edge than just to begin with envision.

step one Introduction

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 her reddit 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 ainsi que al. ( 2016 ) compared observed magnetopause crossings into the Shue mais aussi al. model (Shue ainsi que al., 1997 ) to have half of the past solar power period and found logical distinctions between your model and you will findings. It contended your ionospheric conductivity plus the solar power piece of cake acceleration try extra details one influence the newest magnetopause updates. The analytical investigation means that the typical magnetopause is actually further out-of our planet than predicted through the big date times which have down conductivity and higher solar piece of cake velocity. They advised one to intensification from Ultraviolet light contributes to a rise on the magnetospheric-ionospheric currents one to reduces the magnetized tension during the magnetosphere and you can this new magnetopause actions earthward. To the contrary, improvement of your acceleration intensifies new viscous communications between your solar piece of cake and you will magnetosphere increasing the globally magnetospheric convection and getting way more magnetized flux for the dayside magnetosphere. We’ll talk about this type of assumptions less than about papers.