Vlasiator 6D 'EGI' tail current sheet data series

This is a minimal dataset from the global Vlasiator run 'EGI', spanning time states from 1300-1470s, needed to reconstruct the results of Palmroth et al. (2023). The data contains selected Vlasiator outputs in the tail current sheet box, approximately spanning the following coordinates in the simulation coordinate system (equivalent to the GSE/GSM coordinate systems):
X = [-1.6e+08, -2.8e+07 ] m ~= [-25, -5] RE
Y = [-1.28e+08, 1.28e+08] m ~= [-20, 20] RE
Z = [-3.2e+07, 3.2e+07 ] m ~= [-5, 5] RE
Coordinate data is given in meters; in general, values are in SI units.
The variables given are, all represent cell averages:
- Magnetic field, 'vg_b_vol', units of T
- Electric field, 'vg_e_vol', units of V m^-1
- Proton number density, 'proton/vg_rho', units of m^-3
- Proton bulk velocity, 'proton/vg_v', units of m s^-1
- Proton parallel temperature, 'proton/vg_t_parallel', units of K
- Proton perpendicular temperature, 'proton/vg_t_perpendicular', units of K

The data is given in the VTK format (XML binary), on the Vlasiator refined grid ('SpatialGrid'); filenames of the form 'natgeo_tailbox_minimal_{:04d}.vtu', with the enumeration matching the simulation time in seconds.

The subfolder 'VDFs' contains four proton velocity distribution functions shown in the Palmroth et al. (2023) article. This data is also given in the VTK format (XML binary). Values ('proton') represent the cell-average phase-space density in units of m^-6 s^3. Cells with phase-space density less than 1x10^-15 m^-6 s^3 constitute the Vlasov solver buffer region. The data coordinates are in units of m s^-1 and the velocity coordinates correspond to velocity along the spatial coordinates. The filenames are of form 'velgrid.fig3x.{:09d}.{:04d}.vtu', with the longer number corresponding to spatial cell id and the shorter to simulation time in seconds.

Nomenclature clarification added 2026-03-09:
The name EGI follows the Vlasiator global runs naming convention:

Three letter code: XYZ(Å)

First letter (X)
- A: 2D ecliptic run
- B: 2D Polar run
- C: extended 2D ecliptic run
- D: extended 2D polar run
- E: 3D
- F: 3D with ionosphere
- G-Z: Not yet used

Second letter (Y)
- A: Runs using Leveque Vlasov solver, Hall-less fieldsolver (anno 2013, Hermit)
- B: Runs using Slice3D solver, PPM translation, PQM acceleration (Summer--Autumn 2014, Sisu pilot usage)
- C: Slice 3D, trans PPM, acc PQM with final filtering, field & acc substepping, new ionosphere boundary (version from around christmas 2014)
- D: Vlasiator 3. Slice3D (tPPM,aPQM) unchanged from C, bugfixes and improvements to boundaries, multipop added, vlsv file format changes. (Version from around february 2016)
- E: Vlasiator 3 including all the changes and improvements before fsGrid is merged in. Essentially state on March 1st, 2017.
- F: Vlasiator 4 including some re-runs of the E series, state of April, 2018, just before/after the merge of the fsgrid-multipop-marconi branch, notably also with the reverted whistler speed in upwinding.
- G: Version used in the hero 6D run(s) including translation AMR (1-cell pencils). Includes improved FSgrid communication, vlsv file metadata and renamed output variables.
- H: Version used mostly for the first EuroHPC-JU MICK campaign run.
- I: Version including the copy-condition for inner boundary perturbed magnetic field from Summer 2023.
- J–Z: Not yet used

Third letter (Z)
- A-Z: Individual runs

Possibly fourth letter (Å) used for overflow, if we run out of individual runs.