Dynamics of the Martian bow shock location

2021 ◽  
Author(s):  
Philippe Garnier ◽  
Christian Jacquey ◽  
Vincent Génot ◽  
Beatriz Sanchez-Cano ◽  
Xavier Gendre ◽  
...  
Keyword(s):  
Solar Wind ◽  
Magnetic Fields ◽  
Extreme Ultraviolet ◽  
Dynamic Pressure ◽  
Information Criterion ◽  
Seasonal Effects ◽  
Statistical Parameters ◽  
Cross Correlations ◽  
Shock Location ◽  
Orientation Parameters

<p>The Martian interaction with the solar wind is unique due to the influence of multiple internal and external drivers, including remanent crustal magnetic fields that make the interaction unique. In this work we focus on the analysis of the dynamics of the plasma boundaries that shape the interaction of the planet with its environment, and in particular of the shock whose location varies in a complex way. We use multi spacecraft datasets from three missions (Mars Global Surveyor, Mars Express, Mars Atm-osphere and Volatile Evolution) to provide a coherent picture of the shock drivers. We show how the use of different statistical parameters or cross correlations may modify conclusions. We thus propose the use of refined methods, such as partial correlation analysis or Akaike Information Criterion approach to analyse the multiple drivers of the shock location and rank their relative importance: solar wind dynamic pressure, extreme ultraviolet fluxes, magnetosonic mach number, crustal magnetic fields, but also solar wind orientation parameters. Seasonal effects of crustal fields on the shock, through ionospheric coupling, are also investigated.</p>

The influence of crustal magnetic fields on the Martian bow shock : a statistical analysis of Mars Volatile EvolutioN and Mars Express observations

2020 ◽  
Author(s):  
Philippe Garnier ◽  
Christian Jacquey ◽  
Christian Mazelle ◽  
Xiaohua Fang ◽  
Jacob Gruesbeck ◽  
...  
Keyword(s):  
Solar Wind ◽  
Magnetic Fields ◽  
Extreme Ultraviolet ◽  
Dynamic Pressure ◽  
Bow Shock ◽  
Machine Learning Techniques ◽  
Mars Atmosphere ◽  
Mars Express ◽  
Shock Location ◽  
The Impact

<p>The Martian interaction with the solar wind is unique due to the influence of remanent crustal magnetic fields. The recent studies by the Mars Express and Mars Atmosphere and Volatile Evolution missions underline the strong and complex influence of the crustal magnetic fields on the Martian environment and its interaction with the solar wind. Among them is the influence on the dynamic plasma boundaries that shape this interaction and on the bow shock in particular.</p> <p>Compared to other drivers of the shock location (e.g. solar dynamic pressure, extreme ultraviolet fluxes), the influence of crustal magnetic fields are less understood, with essentially differences observed between the southern and northern hemispheres attributed to the crustal fields. In this presentation we analyze in detail the influence of the crustal fields on the Martian shock location by combining for the first time datasets from two different spacecraft (MAVEN/MEX). An application of machine learning techniques will also be used to increase the list of MAVEN shocks published to date. We show in particular the importance for analyzing biases due to multiple parameters of influence through a partial correlation approach. We also compare the impact of crustal fields with the other parameters of influence, and show that the main drivers of the shock location are by order of importance extreme ultraviolet fluxes and magnetosonic Mach number, crustal fields and then solar wind dynamic pressure.</p>

scholarly journals The responses of the earth’s magnetopause and bow shock to the IMF Bz and the solar wind dynamic pressure: a parametric study using the AMR-CESE-MHD model

2018 ◽  
Vol 8 ◽  
pp. A41 ◽  
Author(s):  
Juan Wang ◽  
Zhifang Guo ◽  
Yasong S. Ge ◽  
Aimin Du ◽  
Can Huang ◽  
...  
Keyword(s):  
Solar Wind ◽  
Mach Number ◽  
Dynamic Pressure ◽  
Bow Shock ◽  
Solar Wind Dynamic Pressure ◽  
The Earth ◽  
Shock Location ◽  
Mhd Model ◽  
Upstream Solar Wind ◽  
The Imf

We have used the AMR-CESE-MHD model to investigate the influences of the IMF Bz and the upstream solar wind dynamic pressure (Dp) on Earth’s magnetopause and bow shock. Our results present that the earthward displacement of the magnetopause increases with the intensity of the IMF Bz. The increase of the northward IMF Bz also brings the magnetopause closer to the Earth even though with a small distance. Our simulation results show that the subsolar bow shock during the southward IMF is much closer to the Earth than during the northward IMF. As the intensity of IMF Bz increases (also the total field strength), the subsolar bow shock moves sunward as the solar wind magnetosonic Mach number decreases. The sunward movement of the subsolar bow shock during southward IMF are much smaller than that during northward IMF, which indicates that the decrease of solar wind magnetosonic Mach number hardly changes the subsolar bow shock location during southward IMF. Our simulations also show that the effects of upstream solar wind dynamic pressure (Dp) changes on both the subsolar magnetopause and bow shock locations are much more significant than those due to the IMF changes, which is consistent with previous studies. However, in our simulations the earthward displacement of the subsolar magnetopause during high solar wind Dp is greater than that predicted by the empirical models.

Mars’ ionopause characterization based on MAVEN and Mars Express observations

2020 ◽  
Author(s):  
Beatriz Sanchez-Cano ◽  
Clara Narvaez ◽  
Mark Lester ◽  
Michael Mendillo ◽  
Majd Mayyasi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Fields ◽  
Electron Density ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Thermal Pressure ◽  
Density Profiles ◽  
Electron Density Profiles

<p>The ionopause is a tangential discontinuity in the ionospheric thermal plasma density profile that marks the upper boundary of the ionosphere for unmagnetized planets. Since only Venus and Mars have no global “dipole” magnetic fields, ionopauses are unique to those planets. For Venus, the ionopause formation is well characterized because the thermal pressure of the ionosphere is usually larger than the solar wind dynamic pressure. For Mars, however, the maximum thermal pressure of the ionosphere is usually insufficient to balance the total pressure in the overlying magnetic pileup boundary. Therefore, the Martian ionopause is not always formed, and when it does, it is highly structured and is located at different altitudes. In this study, we characterise the Martian ionopause formation from the point of view of the electron density and electron temperature, as well as the thermal, magnetic and dynamic pressures. The objective is to investigate under which circumstances the Martian ionopause is formed, both over and far from crustal magnetic fields, and compare to the Venus’ case. We use several multi-plasma and magnetic field in-situ observations from the three deep dip campaigns of the MAVEN mission that occurred on the dayside of Mars (near subsolar point), as well as in-situ solar wind plasma observations from the Mars Express mission. We find that that 36% of the electron density profiles over strong crustal magnetic field regions had an ionopause event in contrast to the 54% of electron density profiles far from strong crustal magnetic field regions. We also find that the topside ionosphere is typically magnetized at mostly all altitudes. The ionopause, if formed, occurs where the total ionospheric pressure (magnetic+thermal) equals the upstream solar wind dynamic pressure.</p>

STRONG SOLAR WIND DYNAMIC PRESSURE PULSES: INTERPLANETARY SOURCES AND THEIR IMPACTS ON GEOSYNCHRONOUS MAGNETIC FIELDS

2015 ◽  
Vol 812 (2) ◽  
pp. 152
Author(s):  
Pingbing Zuo ◽  
Xueshang Feng ◽  
Yanqiong Xie ◽  
Yi Wang ◽  
Xiaojun Xu
Keyword(s):  
Solar Wind ◽  
Magnetic Fields ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Pressure Pulses

Mars’ ionopause: A game of pressures

2020 ◽  
Author(s):  
Beatriz Sanchez-Cano ◽  
Clara Narvaez ◽  
Mark Lester ◽  
Michael Mendillo ◽  
Majd Mayyasi ◽  
...  
Keyword(s):  
Solar Wind ◽  
Magnetic Fields ◽  
Total Pressure ◽  
Dynamic Pressure ◽  
Solar Wind Plasma ◽  
Point Of View ◽  
Tangential Discontinuity ◽  
Pressure Balance ◽  
Thermal Pressure ◽  
Plasma Density Profile

<p>The ionopause is a tangential discontinuity in the ionospheric thermal plasma density profile that marks the upper boundary of the ionosphere for unmagnetized planets. This interface is formed by a balance of pressures, as the ionopause is the region where the total pressure of the ionosphere (ionospheric thermal pressure plus magnetic pressure) balances the solar wind ram pressure. Since only Venus and Mars have no global “dipole” magnetic fields, ionopauses are unique to those planets. For Venus, the ionopause formation is well characterized because the thermal pressure of the ionosphere is usually larger than the solar wind dynamic pressure. For Mars, however, the maximum thermal pressure of the ionosphere is usually insufficient to balance the total pressure in the overlying magnetic pileup boundary. Therefore, the Martian ionopause is not always formed, and when it does, it is located at a large range of altitudes, varies rapidly and is highly structured. In this study, we characterise the Martian ionopause formation from the point of view of the thermal, magnetic and dynamic pressure balance. The objective of this paper is to assess under which circumstances the Martian ionopause is formed, both over and far from crustal magnetic fields. We focus on three MAVEN deep dip campaigns that occurred on the dayside of Mars, and we utilize several multi-plasma and magnetic field in-situ observations from the MAVEN mission, as well as solar wind plasma observations from the Mars Express mission.</p>

scholarly journals Influence of the solar wind dynamic pressure on the ion precipitation: MAVEN observations and simulation results.

2020 ◽  
Author(s):  
Antoine Martinez ◽  
Ronan Modolo ◽  
François Leblanc ◽  
Jean-Yves Chaufray ◽  
Olivier Witasse
Keyword(s):  
Solar Wind ◽  
Extreme Ultraviolet ◽  
Dynamic Pressure ◽  
Minor Component ◽  
Heavy Ion ◽  
Ion Flux ◽  
Solar Wind Dynamic Pressure ◽  
Atmospheric Escape ◽  
Simulation Results ◽  
Spacecraft Data

<div> <p>Abstract</p> </div> <p>In this work, we compare simulation of the precipitating flux for different solar wind dynamic pressure with MAVEN observations. In particular, we focus on the fluxes of precipitating ion towards Mars' atmosphere as seen by MAVEN/SWIA (cs product), an energy and angular ion spectrometer [1]. We also use LatHyS, which is a 3D multispecies parallelized hybrid model that describes the formation of Mars electromagnetic environment induced by its interaction with the solar wind [2]. </p> <p> </p> <p>1. Introduction</p> <p>Although atmospheric sputtering is a minor component of atmospheric escape today, it is thought to have been much more important four billion years ago [3].  Heavy ion precipitation is the primary driver of atmospheric sputtering. At the present epoch, the efficiency of Mars' atmospheric sputtering by precipitating heavy ions to induce atmospheric escape is expected to be small compared to other mechanisms of atmospheric erosion.  However, since the main driver of sputtering is ion precipitation, it is crucial to constrain the dependence of the precipitating ion flux on present solar wind conditions, before any extrapolation to past solar conditions. By comparing simulation results and MAVEN observations, we here investigate the mechanisms controlling the precipitation when the solar wind dynamic pressure change.</p> <p>We will present how the precipitating ion flux, measured by MAVEN/SWIA, is influenced by the solar wind dynamic pressure and will analyze these observations by comparison with simulation results.</p> <p>2. Observations and simulations results</p> <p>We define two sets of different solar wind dynamic pressure from the set of MAVEN observations of the precipitating flux and simulate Mars’ interaction with the solar wind for the average values of the solar parameters (Extreme Ultraviolet irradiance, Interplanetary magnetic field, solar wind density, solar wind speed...) for both sets. We then reconstruct map of the precipitating heavy ion flux at 250km in altitude and the simulated precipitating flux along each MAVEN trajectory used in our analysis.</p> <p>3. Summary</p> <p>Comparing MAVEN observations with models improves our understanding of the parameters that control the precipitating ion flux. By defining two sets, characterized by different solar wind dynamic pressure and modelling them, we present the comparison between models and observations.</p> <p> </p> <p>Acknowledgements</p> <p>This work was supported by the DIM ACAV and the ESA/ESTEC faculty. This work was also supported by CNES “Système Solaire” program and by the “Programme National de Planétologie” and “Programme National Soleil-Terre”. This work is also part of HELIOSARES Project supported by the ANR (ANR-09-BLAN-0223), ANR MARMITE (ANR-13-BS05-0012-02) and ANR TEMPETE (ANR-17-CE31-0016). Spacecraft data used in this paper are archived and available in the Planetary Data System Archive (https://pds.nasa.gov/). Numerical simulation results used in this article can be found in the simulation database (http://impex.latmos.ipsl.fr).</p> <p> </p> <p>References</p> <p>[1] Leblanc F., R. Modolo and al. (2015), Geophys. Res. Lett, 42, 9135-9141, doi : 10.1002/2015GL066170.</p> <p>[2] Modolo, R., et al. (2016), J. Geophys. Res. Space Physics, 121, 6378–6399, doi: 10.1002/2015JA022324.</p> <p>[3] Luhmann, J.G., Johnson, R.E., Zhang, M.H.G., (1992), Geophys. Res. Lett., 19, 21, 2151-2154.</p>

Solar wind dynamic pressure enhancements and polar auroras

1998 ◽  
Vol 22 (9) ◽  
pp. 1305-1308 ◽  
Author(s):  
Y Zhang ◽  
D.J McEwen ◽  
I Oznovich
Keyword(s):  
Solar Wind ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure

scholarly journals Cluster observations of sudden impulses in the magnetotail caused by interplanetary shocks and pressure increases

2005 ◽  
Vol 23 (2) ◽  
pp. 609-624 ◽  
Author(s):  
K. E. J. Huttunen ◽  
J. Slavin ◽  
M. Collier ◽  
H. E. J. Koskinen ◽  
A. Szabo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Dynamic Pressure ◽  
Solar Wind Speed ◽  
Interplanetary Shock ◽  
Wind Pressure ◽  
Shock Propagation ◽  
Interplanetary Shocks ◽  
Maximum Variance ◽  
The Magnetic Field

Abstract. Sudden impulses (SI) in the tail lobe magnetic field associated with solar wind pressure enhancements are investigated using measurements from Cluster. The magnetic field components during the SIs change in a manner consistent with the assumption that an antisunward moving lateral pressure enhancement compresses the magnetotail axisymmetrically. We found that the maximum variance SI unit vectors were nearly aligned with the associated interplanetary shock normals. For two of the tail lobe SI events during which Cluster was located close to the tail boundary, Cluster observed the inward moving magnetopause. During both events, the spacecraft location changed from the lobe to the magnetospheric boundary layer. During the event on 6 November 2001 the magnetopause was compressed past Cluster. We applied the 2-D Cartesian model developed by collier98 in which a vacuum uniform tail lobe magnetic field is compressed by a step-like pressure increase. The model underestimates the compression of the magnetic field, but it fits the magnetic field maximum variance component well. For events for which we could determine the shock normal orientation, the differences between the observed and calculated shock propagation times from the location of WIND/Geotail to the location of Cluster were small. The propagation speeds of the SIs between the Cluster spacecraft were comparable to the solar wind speed. Our results suggest that the observed tail lobe SIs are due to lateral increases in solar wind dynamic pressure outside the magnetotail boundary.

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