Modeling Ionospheric Densities and Flows in Crustal and Draped Magnetic Fields at Mars

2020 ◽  
Author(s):  
Antonio Renzaglia ◽  
Thomas Cravens ◽  
Christopher Fowler ◽  
Ali Rahmati ◽  
Shotaro Sakai ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Langmuir Probe ◽  
Ion Composition ◽  
Ion Density ◽  
Mars Atmosphere ◽  
Neutral Gas ◽  
Flow Speeds ◽  
Flux Measurements ◽  
Static Electron ◽  
Atmospheric Loss

<p>NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) explorer has been in orbit around Mars for over 5 years now, collecting valuable data about the planet. Specifically, the Langmuir Probe and Waves (LPW), the Neutral Gas and Ion Mass Spectrometer (NGIMS), and the Suprathermal and Thermal Ion Composition (STATIC) instruments measure important ionospheric properties. The instruments measure electron densities and temperature (LPW), neutral gas and ion composition (NGIMS), and the properties of escaping ions (STATIC). Electron and ion density and flux measurements are presented. The data indicates significant differences in ion properties between open crustal, closed crustal, and draped magnetic fields. Similar differences are noted for electrons as well. An ionospheric model has been developed that produces a profile of the ionosphere. The model then explores the evolution of the ionosphere, via chemistry and transport. At low altitudes (z<300 km), chemistry dominates, while transport dominates at higher altitudes. Results show significant differences in the ionosphere between the types of fields. The model utilizes data from the Magnetometer (MAG) instrument to provide properties of magnetic fields at Mars. The model may also help explain some of the atmospheric loss occurring at Mars. This is compared to data from STATIC. Analytic arguments for subsonic vs supersonic flow speeds (in the open field case) are also presented.</p>

Hydrogen escape from Mars is driven by seasonal and dust storm transport of water

Science ◽  
2020 ◽  
Vol 370 (6518) ◽  
pp. 824-831
Author(s):  
Shane W. Stone ◽  
Roger V. Yelle ◽  
Mehdi Benna ◽  
Daniel Y. Lo ◽  
Meredith K. Elrod ◽  
...  
Keyword(s):  
Dust Storm ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Dust Storms ◽  
Upper Atmosphere ◽  
Lower Atmosphere ◽  
Mars Atmosphere ◽  
Water Abundance ◽  
Neutral Gas ◽  
Standard Models

Mars has lost most of its once-abundant water to space, leaving the planet cold and dry. In standard models, molecular hydrogen produced from water in the lower atmosphere diffuses into the upper atmosphere where it is dissociated, producing atomic hydrogen, which is lost. Using observations from the Neutral Gas and Ion Mass Spectrometer on the Mars Atmosphere and Volatile Evolution spacecraft, we demonstrate that water is instead transported directly to the upper atmosphere, then dissociated by ions to produce atomic hydrogen. The water abundance in the upper atmosphere varied seasonally, peaking in southern summer, and surged during dust storms, including the 2018 global dust storm. We calculate that this transport of water dominates the present-day loss of atomic hydrogen to space and influenced the evolution of Mars’ climate.

The distribution of molecular and neutral gas and magnetic fields near the bipolar H II region S106

1995 ◽  
Vol 442 ◽  
pp. 208 ◽  
Author(s):  
D. A. Roberts ◽  
R. M. Crutcher ◽  
T. H. Troland
Keyword(s):  
Magnetic Fields ◽  
Neutral Gas ◽  
H Ii Region

scholarly journals Turbulence in the diffuse magneto-ionized medium: observational aspects

2015 ◽  
Vol 11 (A29B) ◽  
pp. 720-722
Author(s):  
Marijke Haverkorn
Keyword(s):  
Magnetic Fields ◽  
Milky Way ◽  
Turbulent Energy ◽  
Spectral Lines ◽  
Observational Methods ◽  
Interstellar Gas ◽  
Ionized Gas ◽  
Neutral Gas ◽  
Velocity Information ◽  
Gas Component

AbstractTurbulence in the interstellar medium is ubiquitous. The turbulent energy density in the gas is significant, and comparable to energy densities of magnetic fields and cosmic rays. Studies of the turbulent interstellar gas in the Milky Way have mostly focused on the neutral gas component, since various spectral lines can give velocity information. Probing turbulent properties in the ionized gas, let alone in magnetic fields, is observationally more difficult. A number of observational methods are discussed below which provide estimates of the maximum scale of fluctuations, the Mach number and other turbulence characteristics.

scholarly journals The Neutral Gas and Ion Mass Spectrometer on the Mars Atmosphere and Volatile Evolution Mission

2014 ◽  
Vol 195 (1-4) ◽  
pp. 49-73 ◽  
Author(s):  
Paul R. Mahaffy ◽  
Mehdi Benna ◽  
Todd King ◽  
Daniel N. Harpold ◽  
Robert Arvey ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Mars Atmosphere ◽  
Neutral Gas

Ionospheric dynamic and coupling processes during geomagnetic storms

2020 ◽  
Author(s):  
Chaosong Huang
Keyword(s):  
Electric Fields ◽  
Geomagnetic Storms ◽  
Equatorial Ionosphere ◽  
Ion Composition ◽  
Hemispheric Differences ◽  
Ion Density ◽  
Ion Drift ◽  
Low Latitudes ◽  
Coupling Processes ◽  
Ionospheric Dynamics

<p>Geomagnetic storms cause the largest disturbances in the ionosphere-thermosphere system. We use measurements with satellites and ground based radars to study storm-induced variations in ionospheric plasma drift, ion density, and ion composition at low latitudes. It is found that the storm-time change of ion drift velocity in the equatorial ionosphere can reach 200-300 m/s, the change of ion density can be one or two orders of magnitude, and the change of ion composition can be 50-80%. These extremely large changes in the ionosphere can last for several hours or even a few days during the main and recovery phases of magnetic storms. The longitudinal, latitudinal and hemispheric differences of storm-time ionospheric disturbances are analyzed from measurements of multiple satellites or radar chain. Very long, continuous penetration of interplanetary electric fields to the equatorial ionosphere for 6 or even 14 hours are observed, and the time when disturbance dynamo electric fields become dominant is identified. The interplay of penetration, shielding, and disturbance dynamo electric fields in the storm-time ionosphere will be addressed. Mechanisms responsible for storm-time ionospheric dynamics will be discussed.</p>

Solar Wind induced waves in the skies of Mars: Ionospheric compression, energization, and escape resulting from the impact of ultra-low frequency magnetosonic waves generated upstream of the Martian bow shock

2020 ◽  
Author(s):  
Glyn Collinson ◽  
Lynn Wilson III ◽  
Nick Omidi ◽  
David Sibeck ◽  
Jared Espley ◽  
...  
Keyword(s):  
Solar Wind ◽  
Low Frequency ◽  
Ulf Waves ◽  
Mars Atmosphere ◽  
Transient Phenomena ◽  
Mars Express ◽  
Linearly Polarized ◽  
Using Data ◽  
Atmospheric Loss ◽  
The Impact

<p>Using data from the NASA Mars Atmosphere and Voltatile EvolutioN (MAVEN) and ESA Mars Express spacecraft, we show that transient phenomena in the foreshock and solar wind can directly inject energy into the ionosphere of Mars. We demonstrate that the impact of compressive Ultra-Low Frequency (ULF) waves in the solar wind on the induced magnetospheres drive compressional, linearly polarized, magnetosonic ULF waves in the ionosphere, and a localized electromagnetic "ringing" at the local proton gyrofrequency. The pulsations heat and energize ionospheric plasmas. A preliminary survey of events shows that no special upstream conditions are required in the interplanetary magnetic field or solar wind. Elevated ion densities and temperatures in the solar wind near to Mars are consistent with the presence of an additional population of Martian ions, leading to ion-ion instablities, associated wave-particle interactions, and heating of the solar wind. The phenomenon was found to be seasonal, occurring when Mars is near perihelion. Finally, we present simultaneous multipoint observations of the phenomenon, with the Mars Express observing the waves upstream, and MAVEN observing the response in the ionosphere. When these new observations are combined with decades of previous studies, they collectively provide strong evidence for a previously undemonstrated atmospheric loss process at unmagnetized planets: ionospheric escape driven by the direct impact of transient phenomena from the foreshock and solar wind.</p>

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