SWIGS: Gorgon Magnetohydrodyamic Code Simulation Data: Magnetospheric and Ionospheric Conditions under Southward IMF for 0-90 degree Dipole Tilts

• Main Authors: Eggington, Joseph, Eastwood, Jonathan, Mejnertsen, Lars, Desai, Ravindra, Chittenden, Jeremy
• Format: Dataset
• Language: English
• Published: Centre for Environmental Data Analysis (CEDA) 2020
• Subjects: Atmospheric sciences and Earth Observation Imagery; North Pole; North Magnetic Pole
• Online Access: https://dx.doi.org/10.5285/77d63a69e3554412a40c9a9ba564e3f9; https://catalogue.ceda.ac.uk/uuid/77d63a69e3554412a40c9a9ba564e3f9

This dataset contains data outputs generated using the Gorgon Magnetohydrodynamic (MHD) code, for simulations of the steady-state magnetosphere-ionosphere system during southward interplanetary magnetic field (IMF) with dipole tilt angles from 0-90 degrees. This data were collected as part of the NERC project Space Weather Impacts on Ground-based Systems (SWIGS). The MHD equations were solved in the magnetosphere on a regular 3-D cartesian grid of resolution 0.5 RE (Earth radii), covering a domain of dimensions (-30,90) RE in X, (-40,40) RE in Y and (-40,40) RE in Z with an inner boundary at 4 RE. In this coordinate system the Sun lies in the negative X-direction, the Z axis is aligned to the dipole in the 0 degree tilt case (where positive tilt points the north magnetic pole towards the Sun), and Y completes the right-handed set. The ionospheric variables were calculated on a separate 2-D spherical grid of dimensions 66x128 in latitude and longitude (with the north pole at 90 degrees latitude and the sun at 180 degrees longitude), coupled to the magnetospheric domain at the inner boundary. Output data is timestamped in seconds and is defined at the centre of the grid cells. The simulation data corresponding to each dipole tilt are stored in separate directories 'XXdeg', e.g. in '00deg' for a 0 degree tilt angle. The data are stored in hdf5 format. The magnetospheric variables are stored in the files 'Gorgon_[YYYYMMDD]_[XX]deg_MS_params_[XXXXX]s.hdf5' where XX is the tilt angle in degrees and XXXXX is the simulation time in seconds. The magnetospheric data includes the magnetic field ('Bvec_c'), plasma bulk velocity ('vvec') and electric current density ('jvec') after 4h of simulation, as well as the magnetic field and velocity in 5 minute intervals for the preceding 30 minutes. The dataset for each magnetospheric variable is of shape (240,160,160,3) where the first 3 dimensions are the grid indices in (X,Y,Z) indexed from negative to positive, and the final dimension is the cartesian vector components in (i,j,k). Similarly, the ionospheric data are stored as 'Gorgon_[YYYYMMDD]_[XX]deg_IS_params_[XXXXX]s.hdf5', containing the field-aligned current ('FAC') and electric potential ('phi') after 4h of simulation, as well as the potential in 5 minute intervals for the preceding 30 minutes. The dataset for each ionospheric variable is of shape (66, 128) where the first dimension is the grid index in colatitude, indexed from the north towards the south (i.e. 0 to 180 degrees), and the second dimension is the grid index in longitude, indexed from midnight towards noon via dawn (i.e. 0 to 360 degrees).