Hybrid simulations of proton precipitation patterns onto the upper atmosphere of Mars

Diéval, Catherine; Kallio, Esa; Stenberg, G.; Barabash, S.; Järvinen, R.

doi:10.5047/eps.2011.08.015

Cited by 12 publications

(40 citation statements)

References 30 publications

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“…In addition, simulations by Diéval et al . [] predict a low energy component (energy < 1 keV) in the precipitating proton spectrum, which we do not measure. One reason is that the instrumental energy cut‐off of IMA, ~1.2 keV in the intermediate PAC level limits the detection of the low‐energy protons.…”

Section: Spatial Distribution and Characteristics Of The Eventsmentioning

confidence: 61%

“…The flux decreases with increasing SZA. This trend is consistent with the results of hybrid modeling studies [ Kallio and Janhunen , ; Diéval et al ., ]…”

Section: Spatial Distribution and Characteristics Of The Eventsmentioning

confidence: 99%

“…Diéval et al . [] reported that the modeled precipitating flux decreases when altitude decreases at all SZA, with a more pronounced decrease in the subsolar region than at higher SZA. We note that the data coverage below the determined IMB is rather poor at low altitudes in the subsolar region (Figure c).…”

Section: Spatial Distribution and Characteristics Of The Eventsmentioning

confidence: 99%

“…The resulting average spectrum is shown in Figure . The spectrum is narrow in energy, in contrast to simulation results that show a broad energy range [ Brecht , ; Kallio and Janhunen , ; Diéval et al ., ]. In addition, simulations by Diéval et al .…”

Section: Spatial Distribution and Characteristics Of The Eventsmentioning

confidence: 99%

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A statistical study of proton precipitation onto the Martian upper atmosphere: Mars Express observations

et al. 2013

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[1] Due to the small size of the Martian magnetic pile-up region, especially at the subsolar point, heated protons with high enough energy can penetrate the induced magnetosphere boundary without being backscattered, i.e., they precipitate. We present a statistical study of the downgoing~keV proton fluxes measured in the Martian ionosphere by the Analyzer of Space Plasma and Energetic Atoms experiment onboard the Mars Express spacecraft. We find that on the dayside, the events of proton penetration occur during 3% of the observation time; the precipitation is an intermittent phenomenon. The proton events carry on average~0.2% of the incident solar wind flux. Therefore, the induced magnetosphere is an effective shield against the magnetosheath protons. The events are more frequent during fast solar wind conditions than during slow solar wind conditions. The sporadic proton penetration is thought to be caused by transient increases in the magnetosheath temperature. The precipitating flux is higher on the dayside than on the nightside, and its spatial deposition is controlled by the solar wind convective electric field. The largest crustal magnetic anomalies tend to decrease the proton precipitation in the southern hemisphere. The particle and energy fluxes vary in the range 10 4 -10 6 cm -2 s -1 and 10 7 -10 9 eVcm -2 s -1 , respectively. The corresponding heating for the dayside atmosphere is on average negligible compared to the solar extreme ultraviolet heating, although the intermittent penetration may cause local ionization. The net precipitating proton particle flux input to the dayside ionosphere is estimated as 1.2 Á 10 21 s -1 .

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Section: Spatial Distribution and Characteristics Of The Eventsmentioning

confidence: 61%

“…The flux decreases with increasing SZA. This trend is consistent with the results of hybrid modeling studies [ Kallio and Janhunen , ; Diéval et al ., ]…”

Section: Spatial Distribution and Characteristics Of The Eventsmentioning

confidence: 99%

Section: Spatial Distribution and Characteristics Of The Eventsmentioning

confidence: 99%

Section: Spatial Distribution and Characteristics Of The Eventsmentioning

confidence: 99%

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A statistical study of proton precipitation onto the Martian upper atmosphere: Mars Express observations

et al. 2013

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“…Locally at the terminator, however, we conclude that 40% of the precipitating H þ flux is solar wind protons. Modelling of proton precipitation on Mars yielded a solar wind proton contribution of 62% (Diéval et al, 2012b).…”

Section: Discussionmentioning

confidence: 99%

Proton and alpha particle precipitation onto the upper atmosphere of Venus

Wieser

Ashfaque

Nilsson

et al. 2015

Planetary and Space Science

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MAVEN observations on a hemispheric asymmetry of precipitating ions toward the Martian upper atmosphere according to the upstream solar wind electric field

et al. 2017

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The Mars Atmosphere and Volatile Evolution (MAVEN) observations show that the global spatial distribution of ions precipitating toward the Martian upper atmosphere has a highly asymmetric pattern relative to the upstream solar wind electric field. MAVEN observations indicate that precipitating planetary heavy ion fluxes measured in the downward solar wind electric field (−E) hemisphere are generally larger than those measured in the upward electric field (+E) hemisphere, as expected from modeling. The −E (+E) hemispheres are defined by the direction of solar wind electric field pointing toward (or away from) the planet. On the other hand, such an asymmetric precipitating pattern relative to the solar wind electric field is less clear around the terminator. Strong precipitating fluxes are sometimes found even in the +E field hemisphere under either strong upstream solar wind dynamic pressure or strong interplanetary magnetic field periods. The results imply that those intense precipitating ion fluxes are observed when the gyroradii of pickup ions are estimated to be relatively small compared with the planetary scale. Therefore, the upstream solar wind parameters are important factors in controlling the global spatial pattern and flux of ions precipitating into the Martian upper atmosphere.

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Hybrid simulations of proton precipitation patterns onto the upper atmosphere of Mars

Cited by 12 publications

References 30 publications

A statistical study of proton precipitation onto the Martian upper atmosphere: Mars Express observations

A statistical study of proton precipitation onto the Martian upper atmosphere: Mars Express observations

Proton and alpha particle precipitation onto the upper atmosphere of Venus

MAVEN observations on a hemispheric asymmetry of precipitating ions toward the Martian upper atmosphere according to the upstream solar wind electric field

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