First Synoptic Images of FUV Discrete Aurora and Discovery of Sinuous Aurora at Mars by EMM EMUS

Lillis, Robert J.; Deighan, Justin; Brain, David; Fillingim, M. O.; Jain, Sonal; Chaffin, Michael; Chirakkil, Krishnaprasad; Matroushi, Hessa Al; Lootah, Fatma; AlMazmi, Hoor; Thiemann, E.; Eparvier, F.; Schneider, N. M.

doi:10.1029/2022gl099820

Cited by 20 publications

(34 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, the new Emirates Mars Mission (EMM) spacecraft has shed new light onto discrete aurora at Mars. While EMM does not have a magnetometer instrument onboard, the Emirates Mars Ultraviolet Spectrometer (EMUS) instrument (Holsclaw et al., 2021) is very sensitive to far UV auroral emissions and has detected a variety of interesting auroral phenomena at Mars (e.g., R. J. Lillis et al., 2022; Chaffin et al., 2022). A future collaborative study utilizing the imaging capacity of EMUS with magnetic field measurements by MAVEN will help further our understanding of the mini‐magnetospheric processes that control the onset of discrete aurora at Mars.…”

Section: Discussionmentioning

confidence: 99%

Evidence for Magnetic Reconnection as the Precursor to Discrete Aurora at Mars

Bowers,

DiBraccio,

Slavin

et al. 2023

JGR Space Physics

Self Cite

View full text Add to dashboard Cite

Discrete aurora at Mars are characterized as localized, short‐lasting ultraviolet emissions on the nightside. They are caused by the precipitation of accelerated electron along open magnetic field lines and their collision with the Martian atmosphere. Discrete auroral emissions detected by the Imaging Ultraviolet Spectrograph (IUVS) instrument onboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft occur most frequently over the strongest crustal magnetic anomalies at Mars and under particular local time and upstream interplanetary magnetic field (IMF) conditions. These trends suggest that the onset of discrete aurora is controlled by the processes that govern the interaction between the draped IMF and the crustal magnetic anomalies. Here, we analyze MAVEN magnetometer measurements over regions of strong crustal fields during 49 discrete auroral events observed by IUVS. Our results indicate that the draped IMF orientations during each discrete auroral event show a clear tendency to be anti‐parallel to the underlying crustal anomaly magnetic fields near the location of the emission onset. This suggests that magnetic reconnection, a process that favors anti‐parallel magnetic field regimes, between the crustal fields and the draped IMF plays a role in discrete aurora formation. Of the 49 discrete auroral events analyzed, 42 (86%) occurred under draped IMF conditions that are susceptible to reconnection with the underlying crustal anomalies. This investigation produces strong evidence linking discrete aurora to magnetic reconnection at Mars and provides insights into other trends in discrete auroral activation such as local time and upstream IMF conditions.

show abstract

Section: Discussionmentioning

confidence: 99%

Evidence for Magnetic Reconnection as the Precursor to Discrete Aurora at Mars

Bowers,

DiBraccio,

Slavin

et al. 2023

JGR Space Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…Different types of aurorae are usually defined according to their particle sources and discrete aurorae are designated for auroral emission caused by accelerated electrons at these two planets, particularly broadband electron acceleration as a consequence of wave‐particle interactions or inverted‐V electron acceleration events. However, this phenomenon is not limited to magnetized planets but also observed at Mars, a planet with only localized strong crustal magnetic fields, by Mars express (Bertaux et al., 2005; Leblanc et al., 2006, 2008), Mars Atmosphere and Volatile EvolutioN (MAVEN) (e.g., Schneider et al., 2018, 2021), and most recently the United Arab Emirates' Hope spacecraft (Lillis et al., [2022, submitted to GRL, MS# 2022GL099820]).…”

Section: Introductionmentioning

confidence: 99%

Nightside Auroral Electrons at Mars: Upstream Drivers and Ionospheric Impact

Mitchell

McFadden

et al. 2022

JGR Space Physics

Self Cite

View full text Add to dashboard Cite

Discrete aurorae have been long observed at Earth's polar region (see review by Birn et al. (2012)) and more recently at Jupiter with observations from the Juno spacecraft (Mauk et al., 2017(Mauk et al., , 2020, both planets possessing an intrinsic global dipole field and a collisional atmosphere. Different types of aurorae are usually defined according to their particle sources and discrete aurorae are designated for auroral emission caused by accelerated electrons at these two planets, particularly broadband electron acceleration as a consequence of wave-particle interactions or inverted-V electron acceleration events. However, this phenomenon is not limited to magnetized planets but also observed at Mars, a planet with only localized strong crustal magnetic fields, by Mars express

show abstract

“…Analysis of dayside limb scans during the transition phase of the EMM mission indicate that modeling both the solar resonant fluorescence and electron impact sources are necessary to replicate the brightness profiles observed by EMUS (Evans et al., 2022; this issue). In addition, analysis of EMUS disk spectra from the nightside of the planet has found that auroral events driven solely by electron impact contain detectable emission at Ar I 106.6 nm (R. Lillis et al., 2022 this issue). These independent results are consistent with the high correlation we find between Ar I 106.6 nm and O I 135.6 nm emissions in the Martian dayglow.…”

Section: Resultsmentioning

confidence: 99%

Emirates Mars Ultraviolet Spectrometer's (EMUS) Observation of Argon in the Martian Thermosphere

Lootah

Deighan

Fillingim

et al. 2022

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

EMM is designed to explore the dynamics of the Martian atmospheric layers on a global scale, simultaneously sampling diurnal, and seasonal timescales (Almatroushi et al., 2021;Amiri et al., 2022). On board the EMM's spacecraft "Hope Probe" are three scientific instruments designed to study these different layers: (a) Emirates eXploration Image (EXI) (Jones et al., 2021) (b) Emirates Infrared Spectrometer (EMIRS) (Edwards et al., 2021) and (c) Emirates Mars Ultraviolet Spectrometer (EMUS) (Holsclaw et al., 2021). EMUS is a far ultraviolet imaging spectrometer designed to investigate the abundance and spatial variability of key neutral species in the thermosphere (100-200 km) and in the exosphere (≥200 km). The EMUS wavelength range is from 100 to 170 nm, detecting key emissions in the upper atmosphere of Mars such as oxygen (135.6 nm, 130.4 nm), hydrogen (Lyman-β: 102.6 nm, Lyman-α: 121.6 nm), carbon monoxide Fourth Positive Group band system (140-170 nm) and argon (104.8 nm, 106.6 nm) (Holsclaw et al., 2021). Motivation to Study Argon on MarsArgon is a photochemically inert gas with molecular weight of 40 g/mol, close to carbon dioxide's (CO 2 ) 44 g/ mol, but does not condense at the temperatures found in the Martian atmosphere. This causes an apparent accumulation of Ar at the winter poles as CO 2 condenses near the surface, and this compositional change propagates to the upper atmosphere, making Ar/CO 2 mixing ratios a useful indicator of vertical transport in the atmosphere of Mars. Understanding the distribution of Ar has been of interest to scientists for some time, as it is a good

show abstract

First Synoptic Images of FUV Discrete Aurora and Discovery of Sinuous Aurora at Mars by EMM EMUS

Cited by 20 publications

References 38 publications

Evidence for Magnetic Reconnection as the Precursor to Discrete Aurora at Mars

Evidence for Magnetic Reconnection as the Precursor to Discrete Aurora at Mars

Nightside Auroral Electrons at Mars: Upstream Drivers and Ionospheric Impact

Emirates Mars Ultraviolet Spectrometer's (EMUS) Observation of Argon in the Martian Thermosphere

Contact Info

Product

Resources

About