On the origin of aurorae on Mars

Brain, David; Halekas, J. S.; Peticolas, L. M.; Lin, R. P.; Luhmann, J. G.; Mitchell, David; Delory, G. T.; Bougher, S. W.; Acuña, M. H.; Rème, H.

doi:10.1029/2005gl024782

Cited by 145 publications

(227 citation statements)

References 17 publications

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“…1 shows our input electron spectrogram. These data were observed by MGS on 21 April 2001 and have been reported in more detail by Brain et al (2006). From 02:10 to 02:30 UT, MGS was at an altitude of about nearly 400 km at a local time of 02 on the night side.…”

Section: Calculating Ionospheric Currentssupporting

confidence: 57%

On wind-driven electrojets at magnetic cusps in the nightside ionosphere of Mars

Fillingim¹,

Lillis²,

England³

et al. 2012

Earth Planet Sp

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Mars has a complex magnetic topology where crustal magnetic fields can interact with the solar wind magnetic field to form magnetic cusps. On the nightside, solar wind electron precipitation can produce enhanced ionization at cusps while closed field regions adjacent to cusps can be devoid of significant ionization. Using an electron transport model, we calculate the spatial structure of the nightside ionosphere of Mars using Mars Global Surveyor electron measurements as input. We find that localized regions of enhanced ionospheric density can occur at magnetic cusps adjacent to low density regions. Under this configuration, thermospheric winds can drive ionospheric electrojets. Collisional ions move in the direction of the neutral winds while magnetized electrons move perpendicular to the wind direction. This difference in motion drives currents and can lead to charge accumulation at the edges of regions of enhanced ionization. Polarization fields drive secondary currents which can reinforce the primary currents leading to electrojet formation. We estimate the magnitude of these electrojets and show that their magnetic perturbations can be detectable from both orbiting spacecraft and the surface. The magnitude of the electrojets can vary on diurnal and annual time scales as the strength and direction of the winds vary. These electrojets may lead to localized Joule heating, and closure of these currents may require field-aligned currents which may play a role in high altitude acceleration processes.

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Section: Calculating Ionospheric Currentssupporting

confidence: 57%

On wind-driven electrojets at magnetic cusps in the nightside ionosphere of Mars

Fillingim¹,

Lillis²,

England³

et al. 2012

Earth Planet Sp

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“…Brain et al (2006a) have observed a clear relationship between the occurrence of peaked electron distributions at the altitude of ∼400 km and the crustal fields. They have also shown that the IMF orientation strongly affects whether these electrons are observed.…”

Section: Peaked Electron Distributions (Inverted "V" Structures)mentioning

confidence: 86%

“…Peaked electron distributions on Mars were observed at different altitudes on MGS and MEX (Brain et al, 2006a;Lundin et al, 2006). Analogy with inverted V structures in the Earth magnetosphere raised the questions whether aurora on Mars exist and whether there are significant field-aligned electric potential drops on the crustal field lines.…”

Section: Peaked Electron Distributions (Inverted "V" Structures)mentioning

confidence: 98%

“…3512 E. M. Dubinin et al: Electrons in Martian magnetosphere plasmas . Observations of peaked electron distributions on Mars Global Surveyor and Mars Express which are similar to the inverted V structures related to the aurora on Earth (Brain et al, 2006a;Lundin et al, 2006) raised the very interesting question whether aurora exists on Mars. The observations of energy peaks in the range of 20-30 eV on electron spectra related to CO 2 -photoelectrons allows tracing of ionospheric plasma far from Mars Frahm et al, 2006) which is important for our understanding of mechanisms of ion scavenging.…”

Section: Introductionmentioning

confidence: 95%

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Access of solar wind electrons into the Martian magnetosphere

et al. 2008

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Abstract. Electrons with energy of ∼40-80 eV measured by the instrument ASPERA-3 on Mars Express and MAG-ER onboard Mars Global Surveyor are used to trace an access of solar wind electrons into the Martian magnetosphere. Crustal magnetic fields create an additional protection from solar wind plasma on the dayside of the Southern Hemisphere by shifting the boundary of the induced magnetosphere (this boundary is often refereed as the magnetic pileup boundary) above strong crustal sources to ∼400 km as compared to the Northern Hemisphere. Localized intrusions through cusps are also observed. On the nightside an access into the magnetosphere depends on the IMF orientation. Negative values of the B yIMF component assist the access to the regions with strong crustal magnetizations although electron fluxes are strongly weakened below ∼600 km. A precipitation pattern at lower altitudes is formed by intermittent regions with reduced and enhanced electron fluxes. The precipitation sites are longitudinally stretched narrow bands in the regions with a strong vertical component of the crustal field. Fluxes ≥10 9 cm −2 s −1 of suprathermal electrons necessary to explain the observed aurora emissions are maintained only for the periods with enhanced precipitation. The appearance of another class of electron distributions -inverted V structures, characterized by peaks on energy spectra, is controlled by the IMF. They are clustered in the hemisphere pointed by the interplanetary electric field that implies a constraint on their origin.

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“…Bulk escape processes associated with Martian crustal fields (Brain et al 2006), trans-terminator flows (Fraenz et al 2010), shear flows at boundaries (Penz et al 2004), and the Martian magnetotail (Dubinin et al 1993;Fedorov et al 2006) may provide significant ion loss. Bulk escape may be the primary source of plasma into the Martian plasma sheet, whereas ambipolar fields may be the primary driver for polar wind outflows of protons into the tail lobes (Dubinin et al 2011) and from other regions magnetically 'open' to interplanetary space.…”

Section: Introductionmentioning

confidence: 99%

MAVEN SupraThermal and Thermal Ion Compostion (STATIC) Instrument

et al. 2015

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The MAVEN SupraThermal And Thermal Ion Compostion (STATIC) instrument is designed to measure the ion composition and distribution function of the cold Martian ionosphere, the heated suprathermal tail of this plasma in the upper ionosphere, and the pickup ions accelerated by solar wind electric fields. STATIC operates over an energy range of 0.1 eV up to 30 keV, with a base time resolution of 4 seconds. The instrument consists of a toroidal "top hat" electrostatic analyzer with a 360• × 90• field-of-view, combined with a time-of-flight (TOF) velocity analyzer with 22.5• resolution in the detection plane. The TOF combines a −15 kV acceleration voltage with ultra-thin carbon foils to resolve H + , He ++ , He + , O + , O + 2 , and CO + 2 ions. Secondary electrons from carbon foils are detected by microchannel plate detectors and binned into a variety of data products with varying energy, mass, angle, and time resolution. To prevent detector saturation when measuring cold ram ions at periapsis (∼ 10 11 eV/cm 2 s sr eV), while maintaining adequate sensitivity to resolve tenuous pickup ions at apoapsis (∼ 10 3 eV/cm 2 s sr eV), the sensor includes both mechanical and electrostatic attenuators that increase the dynamic range by a factor of 10 3 . This paper describes the instrument hardware, including several innovative improvements over previous TOF sensors, the ground calibrations of the sensor, the data products generated by the experiment, and some early measurements during cruise phase to Mars.

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On the origin of aurorae on Mars

Cited by 145 publications

References 17 publications

On wind-driven electrojets at magnetic cusps in the nightside ionosphere of Mars

On wind-driven electrojets at magnetic cusps in the nightside ionosphere of Mars

Access of solar wind electrons into the Martian magnetosphere

MAVEN SupraThermal and Thermal Ion Compostion (STATIC) Instrument

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