Crustal magnetic field advection on Mars from MAVEN observations

2020 ◽  
Author(s):  
Isabela de Oliveira ◽  
Markus Fränz ◽  
Adriane Franco ◽  
Ezequiel Echer
Keyword(s):  
Magnetic Field ◽  
Plasma Flow ◽  
Ionospheric Plasma ◽  
Global Analysis ◽  
Dynamic Pressure ◽  
General Idea ◽  
Mars Atmosphere ◽  
Low Intensity ◽  
Single Orbit ◽  
Field Lines

<p>The plasma environment of Mars is highly influenced by regions of remnant magnetism in the planetary crust, above which mini-magnetospheres are created. In this work, we study whether the ionospheric plasma flow can move crustal magnetic field lines, by the process of advection. According to this hypothesis, the magnetic field lines are dragged away in anti-solar direction, westward at dawn and eastward at dusk-side, due to the day-to-night flow of the ionospheric plasma. The altitude of interest is between 200 km and 1000 km, because the plasma flow velocity is significant in this region.</p><p>MAVEN (Mars Atmosphere and Volatile EvolutioN) data is used for a direct comparison between magnetic field data and a crustal magnetic field model. The difference between the observed and the model field at each point of the grid is a measure of the sum of the induced day magnetic field and the possible displacement of the crustal field lines by advection. The results of the analysis show that, except for the lowest altitude range, minimum value of this difference is always observed for westward shift at dawn-side and eastward shift at dusk-side, in agreement with the expected motion of the crustal magnetic field lines.</p><p>For a general idea of the relative forces between the moving plasma and the crustal fields, we use MAVEN data to analyze the pressures involved in the advection process. These are the dynamic pressure of the ionospheric plasma flow, the magnetic pressure of the field lines and the thermal pressure of the plasma related to the mini-magnetospheres. The balance between these quantities should dictate the occurrence of advection. This analysis suggests that advection could take place at low altitude (up to ~450 km) dawn-side regions above low intensity magnetic fields.</p><p>Although the global analysis results showed agreement with our hypothesis, we could not observe evidence of advection from the local observations in order to unambiguously prove the occurrence of this process. Future works include the investigation of single orbit data in regions of low intensity magnetic field, especially at dawn-side, and also magnetohydrodynamic modeling of the process using the plasma conditions prevalent in the Martian ionosphere.</p>

scholarly journals MAVEN Observations of Periodic Low-altitude Plasma Clouds at Mars

2021 ◽  
Vol 922 (2) ◽  
pp. L33
Author(s):  
Chi Zhang ◽  
Zhaojin Rong ◽  
Hans Nilsson ◽  
Lucy Klinger ◽  
Shaosui Xu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Heavy Ions ◽  
Ionospheric Plasma ◽  
Martian Atmosphere ◽  
Mars Atmosphere ◽  
Ion Escape ◽  
Low Altitude ◽  
Field Lines ◽  
Bulk Plasma

Abstract Ion escape to space through the interaction of solar wind and Mars is an important factor influencing the evolution of the Martian atmosphere. The plasma clouds (explosive bulk plasma escape), considered an important ion escaping channel, have been recently identified by spacecraft observations. However, our knowledge about Martian plasma clouds is lacking. Based on the observations of the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, we study a sequence of periodic plasma clouds that occurred at low altitudes (∼600 km) on Mars. We find that the heavy ions in these clouds are energy-dispersed and have the same velocity, regardless of species. By tracing such energy-dispersed ions, we find the source of these clouds is located in a low-altitude ionosphere (∼120 km). The average tailward moving flux of ionospheric plasma carried by clouds is on the order of 107 cm−2 s−1, which is one order higher than the average escaping flux for the magnetotail, suggesting explosive ion escape via clouds. Based on the characteristics of clouds, we suggest, similar to the outflow of Earth’s cusp, these clouds might be the product of heating due to solar wind precipitation along the open field lines, which were generated by magnetic reconnection between the interplanetary magnetic field and crustal fields that occurred above the source.

Physical and Chemical Processes Research of Isotope Separation in Plasma under Magnetic Field

2014 ◽  
Vol 880 ◽  
pp. 128-133 ◽  
Author(s):  
Vyacheslav F. Myshkin ◽  
Dmitry A. Izhoykin ◽  
Ivan A. Ushakov ◽  
Viktor F. Shvetsov
Keyword(s):  
Magnetic Field ◽  
Carbon Dioxide ◽  
Plasma Flow ◽  
High Frequency ◽  
Isotope Separation ◽  
Carbon Dioxide Concentration ◽  
Plasma Stream ◽  
Reaction Products ◽  
Valence Electrons ◽  
Field Lines

It is known that chemical bonding is only possible when particles with antiparallel valence electrons spins orientation collide [1, 2]. In an external magnetic field unpaired electrons spins precession around the field lines is observed. Precession frequencies of valence electrons of magnetic and nonmagnetic nuclei differ, resulting in a different probability to collide in reactive state for different isotopes. The investigations results of magnetic field influence on the carbon isotopes redistribution between carbon dioxide and disperse carbon in plasmachemical processes are given. Argon-oxygen plasma by a high-frequency generator was produced. Carbon placed into reaction zone by the high-frequency electrode evaporation. The plasmachemical reaction products quenching in the plasma flow at the sampler probe were examined. It is found that the Laval nozzle sampler is more efficient for plasma stream cooling versus the cylindrical sampler. The effects of flow rate, pressure and carbon dioxide concentration on the plasma flow cooling efficiency were estimated.

scholarly journals Plasma Flow and Solar Wind Acceleration in Non-Radial Coronal Magnetic Fields

1983 ◽  
Vol 102 ◽  
pp. 473-477
Author(s):  
H. Biernat ◽  
N. Kömle ◽  
H. Rucker
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Plasma Flow ◽  
Coronal Holes ◽  
Expansion Velocity ◽  
The Sun ◽  
Solar Wind Acceleration ◽  
Coronal Magnetic Fields ◽  
Field Lines ◽  
The Magnetic Field

In the vicinity of the Sun — especially above coronal holes — the magnetic field lines show strong non-radial divergence and considerable curvature (see e.g. Kopp and Holzer, 1976; Munro and Jackson, 1977; Ripken, 1977). In the following we study the influence of these characteristics on the expansion velocity of the solar wind.

scholarly journals Rotation of the magnetic field in Earth's magnetosheath by bulk magnetosheath plasma flow

2006 ◽  
Vol 24 (1) ◽  
pp. 339-354 ◽  
Author(s):  
M. Longmore ◽  
S. J. Schwartz ◽  
E. A. Lucek
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Plasma Flow ◽  
Mean Value ◽  
Flow Coupling ◽  
Parker Spiral ◽  
Magnetic Field Model ◽  
Field Lines ◽  
The Magnetic Field

Abstract. Orientations of the observed magnetic field in Earth's dayside magnetosheath are compared with the predicted field line-draping pattern from the Kobel and Flückiger static magnetic field model. A rotation of the overall magnetosheath draping pattern with respect to the model prediction is observed. For an earthward Parker spiral, the sense of the rotation is typically clockwise for northward IMF and anticlockwise for southward IMF. The rotation is consistent with an interpretation which considers the twisting of the magnetic field lines by the bulk plasma flow in the magnetosheath. Histogram distributions describing the differences between the observed and model magnetic field clock angles in the magnetosheath confirm the existence and sense of the rotation. A statistically significant mean value of the IMF rotation in the range 5°-30° is observed in all regions of the magnetosheath, for all IMF directions, although the associated standard deviation implies large uncertainty in the determination of an accurate value for the rotation. We discuss the role of field-flow coupling effects and dayside merging on field line draping in the magnetosheath in view of the evidence presented here and that which has previously been reported by Kaymaz et al. (1992).

scholarly journals Hydromagnetic Dynamo in Astrophysical Jets

1993 ◽  
Vol 157 ◽  
pp. 367-371 ◽  
Author(s):  
A. Shukurov ◽  
D.D. Sokoloff
Keyword(s):  
Magnetic Field ◽  
Cylindrical Shell ◽  
Plasma Flow ◽  
Wave Number ◽  
Astrophysical Jets ◽  
Thin Cylindrical Shell ◽  
Azimuthal Wave Number ◽  
Hydromagnetic Dynamo ◽  
Field Lines ◽  
Jet Plasma

The origin of a regular magnetic field in astrophysical jets is discussed. It is shown that jet plasma flow can generate a magnetic field provided the streamlines are helical. The dynamo of this type, known as the screw dynamo, generates magnetic fields with the dominant azimuthal wave number m = 1 whose field lines also have a helical shape. The field concentrates into a relatively thin cylindrical shell and its configuration is favorable for the collimation and confinement of the jet plasma.

Investigating the turbulent structure of ionospheric plasma velocities on open and closed magnetic field lines

2007 ◽  
Author(s):  
Gary A. Abel ◽  
Mervyn. P. Freeman ◽  
Gareth Chisham ◽  
Nicholas W. Watkins
Keyword(s):  
Magnetic Field ◽  
Ionospheric Plasma ◽  
Turbulent Structure ◽  
Field Lines

A two-spacecraft study of Mars induced magnetosphere's response to upstream conditions

2020 ◽  
Author(s):  
Katerina Stergiopoulou ◽  
Niklas Edberg ◽  
David Andrews ◽  
Beatriz Sánchez-Cano
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Real Time ◽  
Dynamic Pressure ◽  
Local Magnetic Field ◽  
Mars Atmosphere ◽  
Solar Wind Magnetic Field ◽  
Magnetic Field Magnitude ◽  
Induced Field ◽  
The Imf

<p>We investigate the effects of the upstream solar wind magnetic field on the Martian induced magnetosphere. This is a two-spacecraft study, for which we use Mars Express (MEX) magnetic field magnitude data from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument and Interplanetary Magnetic Field (IMF) measurements and solar wind density and velocity from the magnetometer (MAG) and the Solar Wind Ion Analyzer (SWIA) on board Mars Atmosphere and Volatile EvolutioN (MAVEN), from November 2014 to November 2018. Equally temporally spaced echoes appear in MARSIS' ionograms from which the electron cyclotron frequency and eventually the magnitude of the local magnetic field can be calculated. At the same time solar wind magnetic field data and solar wind parameters from MAG and SWIA respectively are utilized, providing the solar wind input to the Martian system. We make real time comparisons of the IMF and the induced magnetic field in the environment of Mars and we test the ratio B<sub>(MEX)</sub> /B<sub>(MAVEN)</sub>  against various parameters such as the solar wind dynamic pressure, velocity, density, Mach number as well as the Martian seasons, latitudes and heliocentric distances. Additionally, we search for disturbances in IMF which then can be traced in the induced field ultimately revealing the response time of the induced magnetosphere to the solar wind behaviour. <br />MEX and MAVEN measurements combined allow us to investigate the response of the Martian induced magnetosphere to the solar wind magnetic field. Real time comparisons of the IMF and the induced field could help us understand the mechanisms controlling the structure of the Martian induced magnetosphere. </p>

Formation of Plasma-Flow Dike Potential Due to Local ECR along Converging Magnetic-Field Lines

1999 ◽  
Vol 35 (1T) ◽  
pp. 335-339
Author(s):  
Toshiro Kaneko ◽  
Yutaka Miyahara ◽  
Rikizo Hatakeyama ◽  
Noriyoshi Sato
Keyword(s):  
Magnetic Field ◽  
Plasma Flow ◽  
Field Lines

scholarly journals Separatrices: The crux of reconnection

2014 ◽  
Vol 81 (1) ◽  
Author(s):  
Giovanni Lapenta ◽  
Stefano Markidis ◽  
Andrey Divin ◽  
David Newman ◽  
Martin Goldman
Keyword(s):  
Magnetic Field ◽  
Kinetic Energy ◽  
Magnetic Reconnection ◽  
Electromagnetic Fields ◽  
Plasma Flow ◽  
Magnetic Energy ◽  
Laboratory Plasmas ◽  
Field Lines ◽  
Kinetic Physics ◽  
Over Time

Magnetic reconnection is one of the key processes in astrophysical and laboratory plasmas: it is the opposite of a dynamo. Looking at energy, a dynamo transforms kinetic energy in magnetic energy while reconnection takes magnetic energy and returns it to its kinetic form. Most plasma processes at their core involve first storing magnetic energy accumulated over time and then releasing it suddenly. We focus here on this release. A key concept in analysing reconnection is that of the separatrix, a surface (line in 2D) that separates the fresh unperturbed plasma embedded in magnetic field lines not yet reconnected with the hotter exhaust embedded in reconnected field lines. In kinetic physics, the separatrices become a layer where many key processes develop. We present here new results relative to the processes at the separatrices that regulate the plasma flow, the energization of the species, the electromagnetic fields and the instabilities developing at the separatrices.

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