DOI: 10.5061/dryad.djh9w0wb0
title: Solar wind ENA precipitation in the Martian atmosphere: Monte Carlo simulation results

description: Since Mars has an extended hydrogen corona, solar wind protons can charge
 exchange with the atomic constituents to become energetic hydrogen atoms,
 also called "energetic neutral atoms (ENAs)". These ENAs can
 access the Martian atmosphere unhindered by the induced magnetosphere and
 crustal fields and are slowed by collisions until they are either turned
 away from Mars or absorbed by the Martian atmosphere. The manuscript
 (Sorgi Johann et al. ) calibrates a model of ENA precipitation using MAVEN
 spacecraft data and quantifies the hydrogen imparted by the solar wind
 over a decade. The model results used in that paper are produced by ASPEN,
 a test particle model that calculates energy deposited in an atmosphere
 [Jolitz et al. 2017]. This dataset includes the logged positions, types,
 and species impacted in modeled collisions, as well as the positions of
 simulated particles when they cross a predefined grid. This was used to
 build 3D histograms of energy deposition and 3D fluxes as a function of
 altitude.
description: Individual particles with a randomly initialized energy and
 position precipitate into a predefined atmosphere, where they collide with
 constituents per Beer's law and lose energy according to their
 cross-sections of interaction with the atmosphere. Collisions and
 positions of the particles are logged given a predefined array.
description: # Solar wind ENA precipitation in the Martian atmosphere: Monte Carlo
 simulation results
 [https://doi.org/10.5061/dryad.djh9w0wb0](https://doi.org/10.5061/dryad.djh9w0wb0) ## Description of the data and file structure ASPEN (Atmospheric Scattering of Protons, Electrons, and Neutrals, Jolitz et al. 2017) model results of hydrogen atom traversal in an atmosphere (Mars). Particles undergo collisions that can be elastic/inelastic, forward/back scattering, and produce secondaries depending on the type of collision (assessed by relative collision cross-sections). This specific model run was used to quantify hydrogen absorption in the Martian atmosphere. ### Files and variables #### File: DD2\_T0\_N100k\_Rerun.zip **Description:** zip file containing text files * simulation_config_100k_fixedsampling_noheating.yaml: YAML containing the simulation configuration variables for ASPEN, including simulated particle properties (e.g. energy range), atmosphere properties (e.g. species included), and simulation parameters (e.g. domain). * FinalStats.dat: txt with the total duration of the simulation. * simulated_particle_population.txt: plaintext, start and end information of each simulated particle * collisions.txt: plaintext with each collision recorded in the simulation per the config rules. * grids.txt: Lists of the location where particle information is gridded, for the following files: * counts_on_spherical_shells.txt: Location, energy, and impact angles on spherical shells with predefined altitudes from grids.txt. * counts_on_longitude_shells.txt: Location, energy, and impact angles on planes representing predefined longitudes from grids.txt. * counts_on_latitude_shells.txt: Location, energy, and impact angles on planes representing predefined latitudes from grids.txt. * counts_on_yz_planes_at_x.txt: Location, energy, and impact angles on YZ planes with predefined x from grids.txt. * counts_on_xz_planes_at_y.txt: Location, energy, and impact angles on XZ planes with predefined y from grids.txt. * counts_on_xy_planes_at_z.txt: Location, energy, and impact angles on XY planes with predefined z from grids.txt.