Data from: Analysis of collisional and facility effects in a magnetic nozzle plasma expansion

Data from: Analysis of collisional and facility effects in a magnetic nozzle plasma expansion Authors: Manuel Cortés-Hernán, Mario Merino, Diego García-Lahuerta, Eduardo Ahedo Contact email: [e-mail] Date: 10/07/2026 Keywords: Electric Propulsion, Plasma Physics, Magnetic Nozzle, Plasma Plumes, Three-Fluid Model, Discontinuous Galerkin, Facility Effects, Background Pressure Version: 1.0.0 DOI: 10.5281/zenodo.21292507 Abstract This dataset contains the simulation results employed in the article "Analysis of collisional and facility effects in a magnetic nozzle plasma expansion." An axisymmetric, quasineutral three-fluid model (ions, neutrals, electrons) used to simulate the plasma expansion in a magnetic nozzle (MN) under the presence of a neutral population coming from the plasma source or as a homogeneous background. The dataset covers simulations of a nominal case (N) with source-ejected neutrals, a collisionless reference case (B0), and a set of background-pressure cases (B2-B4), each solved for two electron boundary conditions. Dataset Description The data were generated by the FEniCS-based solver DIMAGNO-DG which relies on a zeroth-order Discontinuous Galerkin finite element method on a structured triangular mesh. Six simulation cases are provided, each solved under two electron boundary-condition closures: TCA — Throat local Current Ambipolarity OFW — Outer-boundary Floating Wall The simulation cases are the following: Case ID Description Background pressure [mPa] Utilization Efficiency Nominal case* N Plasma beam with incomplete propellant utilization, source-ejected neutrals only, no background pressure 0 0.65 Collisionless case B0 Collisionless reference case (all collisional terms with neutrals set to zero) 0 1 Collisionless case with M_{i0} = 1 B0m Same as B0, with sonic ion injection at the throat 0 1 Background pressure case 2 mPa B2 Background-pressure case 2 1 Background pressure case 4 mPa B4 Background-pressure case 4 1 Background pressure case 4 mPa in an extended domain (L/R0 = 15) B4e Same as B4, with extended computational domain 4 1 Nominal case serves as a reference for all simulation cases with a domain length of L/R0 = 10, Mi0 = 0.5 and phi_max = 0; unless otherwise specified. Data files The data files are provided in two formats: Raw solver output (.h5 / .xdmf)FEniCS solution fields (mesh + cell data) as written directly by DIMAGNO-DG on the triangular mesh for a DG function space, for each case and boundary condition. Solution is provided for the solved magnitudes: ion density (n), ion z-velocity (u_{iz}), ion x-velocity (u_{ix}), ion y-velocity (u_{iy}), ion total energy (E_i), neutral density (n_n), neutral z-velocity (u_{nz}), neutral x-velocity (u_{nx}), neutral total energy (E_n). Access to DIMAGNO-DG is required to open and post-process this files. Post-processed structured grids (.npy)2D fields interpolated onto a structured grid, together with the corresponding coordinate arrays, for each case and boundary condition. File nomenclature: [quantity]_grid.npy. Z, X: structured grid coordinates (axial and radial directions), non-dimensionalized by R0 Ion quantities n: plasma density jzi, jxi, jyi: ion current density components (axial, radial, azimuthal) ji_plane: in-plane ion current density uzi, uxi, uyi: ion velocity components (axial, radial, azimuthal) ui_plane: in-plane ion velocity ui: ion velocity magnitude pi: ion pressure Ti: ion temperature Ei: ion energy Mi: ion Mach number Neutral quantities nn: neutral density jzn, jxn: neutral current density components (axial, radial) jn_plane: in-plane neutral current density uzn, uxn: neutral velocity components (axial, radial) un: neutral velocity magnitude pn: neutral pressure Tn: neutral temperature En: neutral energy Mn: neutral Mach number Electron quantities and closure functions Te: electron temperature phi: electrostatic potential Phi_big: thermalized potential (Phi) G_e, G_e_nocoll: electron flow function, with and without collisional terms A_Te, A_Te_nocoll: adiabaticity function, with and without collisional terms dA_Te_dpsi, dA_Te_dpsi_nocoll: derivative of A_Te along psi, with and without collisional terms jpare: electron current density parallel to B jperpe: electron current density perpendicular to B (meridian plane) jze, jxe: electron current density components (axial, radial) je_plane: electron current density in the meridian plane je: electron current density magnitude jye, jye_coll, jye_nocoll: azimuthal electron current density (total, collisional contribution, collisionless contribution) jt_plane: total (ion + electron) current density in the meridian plane Magnetic field and geometry Bz, Br: applied magnetic field components (axial, radial) B: applied magnetic field magnitude psi: magnetic streamfunction Collision frequencies and source terms nu_i: ionization frequency Si: ionization source term nu_cex: charge-exchange collision frequency S_cex: charge-exchange source term nu_en: electron-neutral elastic collision frequency nu_ei: electron-ion collision frequency nu_exc: excitation collision frequency nu_e: total effective electron momentum-transfer collision frequency (nu_en + nu_ei + nu_exc) Hall parameters Hall_en: Hall parameter associated with electron-neutral collisions Hall_ei: Hall parameter associated with electron-ion collisions Hall_e: total effective Hall parameter Normalization All stored quantities are non-dimensionalized by: R0 = 1.8 cm B0 = 400 G Te0 = 10 eV mi = A·1.67e-27 kg, with A = 131 (Xe) e = 1.6e-19 C Additional details regarding quantities of specific test variables may be found in the article: "Analysis of collisional and facility effects in a magnetic nozzle expansion" Acknowledgments This work has been carried out as part of the ZARATHUSTRA project, which has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 950466). Additional support came from R&D project PID2023-150052OB-I00 (ADAPT) funded by MICIU/AEI/10.13039/501100011033 and by ERDF, EU. E. Ahedo has been supported by the R&D project PID2022-140035OB-I00 (HEEP) funded by MCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe".