Discovery of a proton aurora at Mars

Deighan, Justin; Jain, Sonal; Chaffin, Michael; Fang, Xiaohua; Halekas, J. S.; Clarke, J. T.; Schneider, Nicholas M.; Stewart, A. I. F.; Chaufray, Jean‐Yves; Evans, J. S.; Stevens, M. H.; Mayyasi, Majd; Stiepen, Arnaud; Crismani, Matteo; McClintock, W. E.; Holsclaw, Gregory M.; Lo, Daniel; Montmessin, Franck; Lefèvre, Franck; Jakosky, B. M.

doi:10.1038/s41550-018-0538-5

Cited by 72 publications

(99 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In this sense, Mars serves as the best archetype for auroral processes on unmagnetized planets in our solar system and beyond. In contrast to previous auroral detections at Mars, the proton aurora is exclusively observed on the dayside and is characterized by enhanced hydrogen Lyman-α emission (121.6 nm) confined to the 120-150 km altitude range in limb viewing observations (Deighan et al, 2016, AGU Fall meeting 2016Ritter et al, 2018). Peak emissions are up to 50% brighter than the optically thick dayglow background across the dayside and typically last a few hours or less.…”

Section: Introductionmentioning

confidence: 64%

“…Finally, the expected characteristics of Lyman-α enhancements based on this model will also be compared with observations of recently discovered proton aurora (Deighan et al, 2016, AGU Fall meeting 2016Ritter et al, 2018) in a future study.…”

Section: Resultsmentioning

confidence: 99%

“…Finally, observations with the SPICAM instrument (Ritter et al, ) and the IUVS spectrograph (Deighan et al, , Fall AGU meeting) have identified a third type, proton aurora , on Mars' dayside as an excess hydrogen Lyman‐α emission confined to Mars' thermosphere. The intermittent additional brightness appears correlated with enhanced solar wind flux conditions.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Monte Carlo Simulations of the Interaction of Fast Proton and Hydrogen Atoms With the Martian Atmosphere and Comparison With In Situ Measurements

et al. 2018

View full text Add to dashboard Cite

We present model results of the interaction of proton and hydrogen atom precipitation with the Martian atmosphere. We use a kinetic Monte Carlo model developed earlier for the analysis of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA‐3) Mars Express data. With the availability of Mars Atmosphere and Volatile Evolution Mission in situ measurements, not only the flux of protons incident on the atmosphere but also their degradation along the orbit may now be described. The comparison of the simulations with data collected with the Solar Wind Ion Analyzer shows that the Monte Carlo model reproduces some of the measured features. The results of comparison between simulations and measurements of the proton fluxes at low altitudes make it possible to infer the efficiency of charge exchange between solar wind and the extended hydrogen corona if the value of the magnetic field is measured simultaneously. We also find that the induced magnetic field plays a very important role in the formation of the backscattered flux and strongly controls its magnitude. At the same time, discrepancies between the modeled and the measured energy spectra of the backscattered protons are pointed out. We suggest that some of the physical processes controlling the upward flux are not fully understood or that the data processing of the measured backscattered proton flux should be improved.

show abstract

Section: Introductionmentioning

confidence: 64%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Monte Carlo Simulations of the Interaction of Fast Proton and Hydrogen Atoms With the Martian Atmosphere and Comparison With In Situ Measurements

et al. 2018

View full text Add to dashboard Cite

show abstract

“…They occur following solar activity events such as coronal mass ejections or compression events and were observed in the northern hemisphere in region, although they are believed to be global. Finally, enhancements of the Lyman-α emission have been occasionally seen in the dayside thermosphere with SPICAM (Ritter et al, 2018) and IUVS (Deighan et al, 2018) instruments. The peak altitude of the additional emission ranged from about 120 to 140 km and the excess brightness was between a few hundred Rayleighs (R) and 3 kilo Rayleighs (kR).…”

Section: Introductionmentioning

confidence: 90%

Lyman-α emission in the Martian proton aurora: Line profile and role of horizontal induced magnetic field

Gérard

Hubert

Ritter

et al. 2019

Icarus

View full text Add to dashboard Cite

Enhancements of the dayside Lyman-α emission by as much as ∼50% have been observed between 120 and 130 km in the lower Martian thermosphere from the Mars Express and MAVEN satellites, usually following solar events such as coronal mass ejections and corotating interaction regions. They have been assumed to be optical signatures of proton aurora related to an increase in the solar wind proton flux hitting Mars' bow shock. We present model simulations of the Lyman-α line profiles at different altitudes. These are partly guided by in situ measurements of the energy spectrum of protons in the magnetosheath region by the SWIA instrument on board the MAVEN spacecraft. We show that the auroral Lyman-α line profile is significantly broader than the hydrogen core of the planetary thermal H atom. Consequently, most of the auroral emission is produced outside the optically thick hydrogen core and creates the observed intensity enhancement. Simulations with incident energetic hydrogen atoms (H ENAs) produce a somewhat broader line profile. Monte Carlo calculations are made separately for incident solar wind protons and H ENAs produced by charge exchange in the hydrogen corona. Absorption by CO 2 along the line of sight significantly affects the intensity distribution in the lower thermosphere. The calculated altitude of the peak emission for both types of incident particles is consistent with the observed characteristics of the proton aurora. We show that the presence of a horizontal induced magnetic field somewhat increases the line width and decreases the altitude of the emission peak as a consequence of the magnetic barrier effect on proton precipitation. The brightness of the Lyman-α emission also drops as a result of increased magnetic shielding of the protons.

show abstract

“…Mars Atmosphere and Volatile EvolutioN/IUVS also discovered a third form called proton aurora occurring on Mars' dayside, caused by penetrating protons from the solar wind (Deighan et al, ; Halekas, ). The MAVEN/IUVS detection of proton aurora prompted a search in the Mars Express SPICAM archive (Ritter et al, ), finding six events and confirming the existence of the phenomenon.…”

Section: Introductionmentioning

confidence: 99%

Global Aurora on Mars During the September 2017 Space Weather Event

Schneider

Jain

Deighan

et al. 2018

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

We report the detection of bright aurora spanning Mars' nightside during the space weather event occurring in September 2017. The phenomenon was similar to diffuse aurora detected previously at Mars, but 25 times brighter and detectable over the entire visible nightside. The observations were made with the Imaging UltraViolet Spectrograph, a remote sensing instrument on the Mars Atmosphere and Volatile EvolutioN spacecraft orbiting Mars. Images show that the emission was brightest around the limb of the planet, with a fairly uniform faint glow against the disk itself. Spectra identified four molecular emissions associated with aurora, and limb scans show the emission originated from an altitude of ~60 km in the atmosphere. Both are consistent with very high energy particle precipitation. The auroral brightening peaked around 13 September, when the flux of solar energetic electrons and protons both peaked. During the declining phase of the event, faint but statistically significant auroral emissions briefly appeared against the disk of the planet in the form of narrow wisps and small patches. These features are approximately aligned with predicted open field lines in the region of strong crustal magnetic fields in Mars' southern hemisphere.

show abstract

Discovery of a proton aurora at Mars

Cited by 72 publications

References 29 publications

Monte Carlo Simulations of the Interaction of Fast Proton and Hydrogen Atoms With the Martian Atmosphere and Comparison With In Situ Measurements

Monte Carlo Simulations of the Interaction of Fast Proton and Hydrogen Atoms With the Martian Atmosphere and Comparison With In Situ Measurements

Lyman-α emission in the Martian proton aurora: Line profile and role of horizontal induced magnetic field

Global Aurora on Mars During the September 2017 Space Weather Event

Contact Info

Product

Resources

About