Data of 3D MHD Simulation for manuscript "An almost complete disappearance of open-flux polar cap for strongly northward interplanetary magnetic field"
Creators: name: Wang, Xiang-Yu
name: Zhang, Qing-He
name: Wang, Chi
name: Tang, Bin-Bin
Publisher: name: Zenodo
Year: 2022

description: Data of 3D MHD Simulation for manuscript "An almost complete disappearance of open-flux polar cap for strongly northward interplanetary magnetic field" These data come from a fully run of a 3D MHD Simulation model that is named PPMLR-MHD model (detailed descriptions below). There are 2 types of data files: 1) Zh15adXXXX.mat is saved simulation parameters. XXXX is the number of files. 2) Zh15ad0312_R6_parameters.fig is matlab figure which contains data about Z=0Re and Y=0Re from Zh15ad0312.mat. The first type files of data include the following parameters: time, x, y, z, logrho, Vx, Vy, Vz, Bx, By, Bz, Pr, Jx, Jy, Jz Where, time is simulation time, which need to plus the start time to transfer them to universal time: time+5:57; (x,y,z) are the three components of the position of simulation point in GSM coordinates; logrho is the plasma density at the simulation point; (Vx, Vy,Vz) are the three components of plasma velocity at the simulation point in GSM coordinates; (Bx, By,Bz) are the three components of magnetic field at the simulation point in GSM coordinates; Pr is the plasma dynamic presure at the simulation point; (Jx, Jy,Jz) are the three components of plasma electric current at the simulation point in GSM coordinates; The second type file of data includes the simulated FAC, part of the field lines. density and velocity. PPMLR-MHD model The PPMLR-MHD model is on the basis of an extension of the piecewise parabolic method (1) with a Lagrangian remap to magnetohydrodynamics (MHD) (2, 3). It is a three-dimensional MHD model, designed specially for the solar wind–magnetosphere–ionosphere system (4-6). The model possesses a high resolution in capturing MHD shocks and discontinuities and a low numerical dissipation in examining possible instabilities inherent in the system (4). The model uses a Cartesian coordinate system with the Earth’s center at the origin and X, Y, and Z axes pointing towards the Sun, the dawn-dusk direction, and the north, respectively. The size of the numerical box extends from 25 RE to –100 RE along the Sun-Earth line and from –50 RE to 50 RE in Y and Z directions, with 240×240×240 grid points and a minimum grid spacing of 0.2 RE. An inner boundary of radius 3 RE is set for the magnetosphere to avoid the complexities associated with the plasmasphere and large MHD characteristic velocity from the strong magnetic field (6). An electrostatic ionosphere shell with height-integrated conductance is imbedded, allowing an electrostatic coupling process introduced between the ionosphere and the magnetospheric inner boundary. The Earth’s magnetic field is approximated by a dipole field with a dipole moment of 8.06×1022 A/m in magnitude. The model is run to solve the whole system by inputting the real interplanetary conditions for the current event. Reference P. Colella, P. R. Woodward, The piecewise parabolic method (PPM) for gas-dynamical simulations. J. Comput. Phys.54, 174– 201 (1984). Y. Q. Hu, X. C. Guo, C. Wang, On the ionospheric and reconnection potentials of the Earth: Results from global MHD simulations. J. Geophys. Res. 112, A07215 (2007). B. B. Tang, C. Wang, Large scale current systems developed from substorm onset: Global MHD results. SCIENCE CHINA Technological Sciences, 61(3): 389-396(2018). C. Wang et al. Magnetohydrodynamics (MHD) numerical simulations on the interaction of the solar wind with the magnetosphere: A review. Sci. China, Ser. D Earth Sci., 56(7), 1141–1157 (2013). X. Guo, C. Wang, Y. Hu,Global MHD simulation of the Kelvin-Helmholtz instability at the magnetopause for northward interplanetary magnetic field. J. Geophys. Res. 115, A10218 (2010). W. Li, C. Wang, B. Tang, X. Guo, D. Lin, Global features of Kelvin-Helmholtz waves at the magnetopause for northward interplanetary magnetic field. J. Geophys. Res. Space Physics. 118, 5118–5126 (2013).