Work Description

Title: Magnetically Controlled Ionosphere of Mars: A Model Analysis with Neutral Wind Effects Open Access Deposited

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Methodology
  • The derived data on the Martian neutral winds and ion drifts are the results of a model analysis of the electron density profiles observed by the MAVEN/ROSE and Mars Express spacecraft. Our model is a one-dimensional chemical diffusive model that self-consistently solves continuity and flux equations to obtain numerical solutions for ion density and flux for each of the six ion species CO2+, CO+, O2+, O+, NO+, and H+. The main source ions in the model are CO2+ and O+, produced in the upper atmosphere by solar EUV radiation and photoelectrons. A secondary source of ionization resulting from solar wind electron precipitation typically occurs in magnetic cusps is also included in the model. Our model is a coupled finite difference primitive equations model that solves for plasma densities and vertical ion fluxes from an altitude of 100 km to 400 km with an evenly increasing altitude grid of 2 km. A steady-state numerical solution is obtained for all ions by solving the finite difference versions of the continuity and flux equations using a generalized Newton’s method.
Description
  • We use our 1-D chemical diffusive model to quantify the physical processes necessary to interpret the day-side ionospheric measurements acquired with radio occultation techniques at the southern high-latitude region of Mars, where the crustal magnetic field is strong and near-vertical in orientation. To interpret the measured ionospheric structure at altitudes where plasma transport dominates, we find it is necessary to impose field-aligned vertical plasma drifts caused by the motion of neutral winds. The most interesting finding of this study is that both upward (between 110 m/s and 150 m/s) and downward (between -55 m/s and -120 m/s) drifts are required to maintain the topside Ne distribution comparable with the measured distribution. We also find that a fixed velocity boundary condition at the upper boundary with a sizeable upward ion velocity is needed to encounter any unexpected ion accumulation in the topside ionosphere to limit the Martian ion outflow. Given the complex nature of neutral dynamics and its relationship to plasma transport processes over magnetic anomalies, we consider that a simple model, such as we have developed, is still capable of yielding valuable insights relating to the neutral wind system at Mars.
Creator
Depositor
  • tariqm@umich.edu
Contact information
Discipline
Funding agency
  • Other Funding Agency
  • National Aeronautics and Space Administration (NASA)
Other Funding agency
  • Mohamed Bin Rashid Space Center, Dubai, UAE
Keyword
Resource type
Last modified
  • 11/19/2022
Published
  • 04/14/2021
Language
DOI
  • https://doi.org/10.7302/vp3q-6d50
License
To Cite this Work:
Majeed, T. (2021). Magnetically Controlled Ionosphere of Mars: A Model Analysis with Neutral Wind Effects [Data set], University of Michigan - Deep Blue Data. https://doi.org/10.7302/vp3q-6d50

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Files (Count: 11; Size: 70.8 KB)

Thumbnailthumbnail-column Title Original Upload Last Modified File Size Access Actions
README_File.txt 2021-04-14 2021-04-14 3.62 KB Open Access
Best_FIT_Model_file_for_Figure2.dat 2021-04-13 2021-04-13 14.3 KB Open Access
Model_file_Diffusive_Equil_Figure2.dat 2021-04-13 2021-04-13 1.1 KB Open Access
Best_FIT_Model_file_for_Figure3.dat 2021-04-13 2021-04-13 14.3 KB Open Access
Model_file_Diffusive_Equil_Figure3.dat 2021-04-13 2021-04-13 3.69 KB Open Access
Model_file_for_flux_Figure4.dat 2021-04-13 2021-04-13 12.5 KB Open Access
Model_WD_For_Figure4.dat 2021-04-14 2021-04-14 3.71 KB Open Access
Model_file_for_flux_Figure5.dat 2021-04-13 2021-04-13 12.5 KB Open Access
Model_WD_For_Figure5.dat 2021-04-13 2021-04-13 3.69 KB Open Access
MAVEN-ROSE_Table2.dat 2021-04-14 2021-04-14 694 Bytes Open Access
MEX-MaRS_Table2.dat 2021-04-14 2021-04-14 690 Bytes Open Access

The Martian neutral winds, ion drifts, and ion fluxes are derived by reproducing the electron density profiles observed by the
MAVEN/ROSE and Mars Express spacecraft. We use our 1-D chemical diffusive model to interpret the measured ionospheric structure
at altitudes where plasma transport dominates. We find it is necessary to impose field-aligned vertical plasma drifts caused by
the motion of neutral winds. The following files can be used to reproduce the model results derived in this paper. Note that
the units of the parameters are given in the header of each file.

1) Best Fit_model_file_for_Figure2.dat. This file provides the best fitted electron density (Ne) (cm-3) profile to the Mars
Express Ne (cm-3) profile. It aslo provides the corresponding ion densities.
The header of this file reads as: HEIGHT (cm) CO2+ (cm-3) CO+ (cm-3) O2+ (cm-3) O+ (cm-3) NO+ (cm-3) H+ (cm-3) Ne (cm-3)

2) Best Fit_model_file_for_Figure3.dat. This file provides the best fitted electron density (Ne) (cm-3) profile to the
MAVEN/ROSE Ne (cm-3) profile. It also provides the corresponding ion densities.
The header of this files reads as: HEIGHT (cm) CO2+ (cm-3) CO+ (cm-3) O2+ (cm-3) O+ (cm-3) NO+ (cm-3) H+ (cm-3) Ne (cm-3)

3) Model_file_diffusive_equil_Figure2.dat. This file provides the model electron density (Ne) (cm-3) profile from simple
model (with no top boundary ion fluxes and no vertical drift is applied) in comparison to the Mars Express Ne (cm-3) profile.
The header of this files reads as: Height (km) Ne (cm-3)

4) Model_file_diffusive_equil_Figure3.dat. This file provides the model electron density (Ne) (cm-3) profile from simple
model (with no top boundary ion fluxes and no vertical drift is applied) in comparison to the MAVEN/ROSE Ne profile.
The header of this files reads as: Height (km) Ne (cm-3)

5) Model_file_for_flux_Figure4.dat. This file provides the derived ion fluexes (cm-2 s-1) at the Mars Express location.
The header of this files reads as: Altitude (cm) Co2+ (cm-2 s-1) CO+ (cm-2 s-1) O2+ (cm-2 s-1)
O+ (cm-2 s-1) NO+ (cm-2 s-1) H+ (cm-2 s-1)

6) Model_file_for_flux_Figure5.dat. This file provides the derived ion fluexes and vertical ion drifts (WD) at the
MAVEN/ROSE location.
The header of this files reads as: Altitude (cm) Co2+ (cm-2 s-1) CO+ (cm-2 s-1) O2+ (cm-2 s-1)
O+ (cm-2 s-1) NO+ (cm-2 s-1) H+ (cm-2 s-1)

7) Model_WD_for_Figure4.dat. This file provides the derived vertical ion drifts (WD) (cm/s) at the Mars Express location.
The header of this files reads as: Altitude(cm) WD (cm/s)

8) Model_WD_for_Figure5.dat. This file provides the derived vertical ion drifts (WD) (cm/s) at the MAVEN/ROSE location.
The header of this files reads as: Altitude(cm) WD (cm/s)

Table2 shows the derived neutral wind speeds at MEX/MaRS and MAVEN/ROSE locations in the paper. The zonal (Un) and
meridional (Vn) winds are the components in terms of Un sinδ and Vn cosδ. Un and Vn are calculated from WD formulation
given in the paper as equation 3. To reproduce this Table2, one needs to have the following parameters.

Ion-neutral collision frequency (νi)
Ion Gyro-frequency (Ωi)
Magnetic inclination angle (I)
Magnetic declination angle (δ)

These parameters are given in files MEX-MaRS_Table2.dat and MAVEN-ROSE_Table2.dat at different altitudes (in km) at MEX/RaRS and
MAVEN-ROSE locations, respectively.

The header of MEX-MaRS_Table2.dat file reads as: Altitude (km) νi (1/s) Ωi (1/s) I (deg) δ (deg)
The header of MAVEN-ROSE_Table2.dat file reads as: Altitude (km) νi (1/s) Ωi (1/s) I (deg) δ (deg)

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