scholarly journals MAVEN unlocks secrets of the Martian atmosphere

Eos ◽  
2014 ◽  
Author(s):  
Harvey Leifert
Keyword(s):  
Solar Wind ◽  
Martian Atmosphere ◽  
Low Altitude

In its first month, NASA’s orbiter saw effects of the solar wind at low altitude and tracked a plume of gases escaping into space

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.

scholarly journals Cusp-like plasma in high altitudes: a statistical study of the width and location of the cusp from Magion-4

2002 ◽  
Vol 20 (3) ◽  
pp. 311-320 ◽  
Author(s):  
J. Mĕrka ◽  
J. Šafránková ◽  
Z. Nĕmeček
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
High Altitudes ◽  
Data Set ◽  
Latitudinal Dependence ◽  
Merging Process ◽  
Low Altitude ◽  
Field Lines ◽  
The Magnetic Field ◽  
Dipole Tilt

Abstract. The width of the cusp region is an indicator of the strength of the merging process and the degree of opening of the magnetosphere. During three years, the Magion-4 satellite, as part of the Interball project, has collected a unique data set of cusp-like plasma observations in middle and high altitudes. For a comparison of high- and low-altitude cusp determination, we map our observations of cusp-like plasma along the magnetic field lines down to the Earth’s surface. We use the Tsyganenko and Stern 1996 model of the magnetospheric magnetic field for the mapping, taking actual solar wind and IMF parameters from the Wind observations. The footprint positions show substantial latitudinal dependence on the dipole tilt angle. We fit this dependence with a linear function and subtract this function from observed cusp position. This process allows us to study both statistical width and location of the inspected region as a function of the solar wind and IMF parameters. Our processing of the Magion-4 measurements shows that high-altitude regions occupied by the cusp-like plasma (cusp and cleft) are projected onto a much broader area (in magnetic local time as well as in a latitude) than that determined in low altitudes. The trends of the shift of the cusp position with changes in the IMF direction established by low-altitude observations have been confirmed.Key words. Magnetospheric physics (magnetopause, cusp and boundary layer; solar wind – magnetosphere interactions)

scholarly journals Capture of solar wind alpha-particles by the Martian atmosphere

2009 ◽  
Vol 36 (23) ◽  
Author(s):  
G. M. Chanteur ◽  
E. Dubinin ◽  
R. Modolo ◽  
M. Fraenz
Keyword(s):  
Solar Wind ◽  
Martian Atmosphere ◽  
Alpha Particles

scholarly journals <i>Letter to the Editor</i>A statistical study of the location and motion of the HF radar cusp

2002 ◽  
Vol 20 (2) ◽  
pp. 275-280 ◽  
Author(s):  
T. K. Yeoman ◽  
P. G. Hanlon ◽  
K. A. McWilliams
Keyword(s):  
Solar Wind ◽  
Continuous Monitoring ◽  
Large Scale ◽  
Statistical Study ◽  
Hf Radar ◽  
Auroral Ionosphere ◽  
Cusp Region ◽  
The North ◽  
Low Altitude ◽  
Spacecraft Data

Abstract. The large-scale and continuous monitoring of the ionospheric cusp region offered by HF radars has been exploited in order to examine the statistical location and motion of the equatorward edge of the HF radar cusp as a function of the upstream IMF BZ component. Although a considerable scatter is seen, both parameters have a clear influence from the north-south component of the IMF. Excellent agreement is achieved with previous observations from low altitude spacecraft data. The HF radar cusp region is seen to migrate equatorward at a rate of 0.02° min-1 nT-1 under IMF BZ south conditions, but remains static for IMF BZ north. The motion of the cusp implies an addition of magnetic flux of ~ 2 × 104 Wbs-1 nT-1 under IMF BZ south conditions, equivalent to a reconnection voltage of 20 kV nT-1, which is consistent with previous estimates from case studies on both the dayside and nightside regions.Key words. Ionosphere (auroral ionosphere) – Magnetospheric physics (magnetosphere-ionosphere interaction; solar wind magnetosphere interactions)

Recent ionospheric observations relating to solar-wind-magnetosphere coupling

1989 ◽  
Vol 328 (1598) ◽  
pp. 93-105 ◽  
Keyword(s):  
Solar Wind ◽  
Interplanetary Medium ◽  
Spatial Scales ◽  
Driving Mechanism ◽  
Reconnection Rate ◽  
Dayside Magnetopause ◽  
Solar Wind Flow ◽  
High Latitude Ionosphere ◽  
Low Altitude ◽  
Statistical Surveys

Simultaneous observations in the high-latitude ionosphere and in the near-Earth interplanetary medium have revealed the control exerted by the interplanetary magnetic field and the solar wind flow on field-perpendicular convection of plasma in both the ionosphere and the magnetosphere. Previous studies, using statistical surveys of data from both low-altitude polar-orbiting satellites and ground-based radars and magnetometers, have established that magnetic reconnection at the dayside magnetopause is the dominant driving mechanism for convection. More recently, ground-based data and global auroral images of higher temporal resolution have been obtained and used to study the response of the ionospheric flows to changes in the interplanetary medium. These observations show that ionospheric convection responds rapidly (within a few minutes) to both increases and decreases in the reconnection rate over a range of spatial scales, as well as revealing transient enhancements which are also thought to be related to magnetopause phenomena. Such results emphasize the potential of ground-based radars and other remotesensing instruments for studies of the Earth’s interaction with the interplanetary medium.

scholarly journals Modeling of the O+pickup ion sputtering efficiency dependence on solar wind conditions for the Martian atmosphere

2014 ◽  
Vol 119 (1) ◽  
pp. 93-108 ◽  
Author(s):  
Yung-Ching Wang ◽  
Janet G. Luhmann ◽  
François Leblanc ◽  
Xiaohua Fang ◽  
Robert E. Johnson ◽  
...  
Keyword(s):  
Solar Wind ◽  
Martian Atmosphere ◽  
Ion Sputtering
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