The September 2017 SEP Event in Context With the Current Solar Cycle: Mars Express ASPERA‐3/IMA and MAVEN/SEP Observations

Ramstad, Robin; Holmström, Mats; Futaana, Yoshifumi; Lee, Christina O.; Rahmati, Ali; Dunn, P.; Lillis, R. J.; Larson, D. E.

doi:10.1029/2018gl077842

Cited by 17 publications

(28 citation statements)

References 12 publications

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“…In the following,

{\overset{true¯}{italicVar}}_{0}

is the average solar parameter at a time t 0 before the periapsis and

{\overset{true¯}{italicVar}}_{1}

is the average solar parameters at a time t 1 after the periapsis. We then linearly interpolated the reconstructed solar wind parameters from

{\overset{true¯}{italicVar}}_{0}

and

{\overset{true¯}{italicVar}}_{1}

to the time t when we reconstructed the precipitating ion flux (as in section ) using the following relation:

Var = {\overset{true¯}{italicVar}}_{0} + ((), {\overset{true¯}{italicVar}}_{1} - {\overset{true¯}{italicVar}}_{0}) * \frac{t - t_{0}}{t_{1} - t_{0}}

In order to estimate an uncertainty for these reconstructed solar wind parameters, we considered the dispersion of the reconstructed solar wind values at t 0 and t 1 . To verify the validity of our methods, we also compared these results with Mars Express measurements of the density and speed of the solar wind using ASPERA‐3 (Barabash et al, ; Ramstad et al, ). In Figure , we displayed our interpolated solar wind parameters (in orange) and the Mars Express measured values (in blue): the solar wind density (Figure a) and the solar wind speed (Figure b).…”

Section: Methodsmentioning

confidence: 99%

“…In order to estimate an uncertainty for these reconstructed solar wind parameters, we considered the dispersion of the reconstructed solar wind values at t 0 and t 1 . To verify the validity of our methods, we also compared these results with Mars Express measurements of the density and speed of the solar wind using ASPERA-3 (Barabash et al, 2006;Ramstad et al, 2018). In Figure 2, we displayed our interpolated solar wind parameters (in orange) and the Mars Express measured values (in blue): the solar wind density (Figure 2a) and the solar wind speed (Figure 2b).…”

Section: Reconstruction Of the Solar Conditions During Maven Periapsimentioning

confidence: 98%

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Variability of Precipitating Ion Fluxes During the September 2017 Event at Mars

et al. 2019

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In this work, we study the influence of the September 2017 solar event on the precipitating heavy ion fluxes toward Mars' atmosphere as seen by Mars Atmosphere and Volatile EvolutioN/Solar Wind Ion Analyzer, an energy and angular ion spectrometer and by Mars Atmosphere and Volatile EvolutioN/Suprathermal and Thermal Ion Composition instrument, an energy, mass, and angular ion spectrometer. After a careful reconstruction of the background induced by the Solar Energetic Particle event in the Mars Atmosphere and Volatile EvolutioN/Solar Wind Ion Analyzer spectrometer, we investigate the precipitating ion flux responses to the space weather events that took place in September 2017. This period is a unique opportunity to analyze the respective role of various possible drivers of heavy ion precipitation into Mars' atmosphere with a wide range of different space weather events occurring during the same month. This study shows an increase in the precipitation flux by more than 1 order of magnitude during the arrival of the September Interplanetary Coronal Mass Ejection compared to the average flux during quiet solar conditions. We also showed that among the possible solar drivers, the solar wind dynamic pressure is the most significant during September 2017.

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“…In the following,

{\overset{true¯}{italicVar}}_{0}

is the average solar parameter at a time t 0 before the periapsis and

{\overset{true¯}{italicVar}}_{1}

is the average solar parameters at a time t 1 after the periapsis. We then linearly interpolated the reconstructed solar wind parameters from

{\overset{true¯}{italicVar}}_{0}

and

{\overset{true¯}{italicVar}}_{1}

to the time t when we reconstructed the precipitating ion flux (as in section ) using the following relation:

Var = {\overset{true¯}{italicVar}}_{0} + ((), {\overset{true¯}{italicVar}}_{1} - {\overset{true¯}{italicVar}}_{0}) * \frac{t - t_{0}}{t_{1} - t_{0}}

Section: Methodsmentioning

confidence: 99%

Section: Reconstruction Of the Solar Conditions During Maven Periapsimentioning

confidence: 98%

Variability of Precipitating Ion Fluxes During the September 2017 Event at Mars

et al. 2019

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“…Effects of the solar storms on Mars and its surrounding space environment were also significant. The September 2017 event produced the largest SEP event seen by MAVEN since its arrival at Mars in 2014 and the fourth largest seen by Mars Express since its arrival at Mars in 2004 (Ramstad et al., 2018). SEPs significantly enhanced nightside ionosphere densities, producing peak electron densities of 1–2 × 10 4 cm −3 around 120 km altitude (Harada et al., 2018).…”

Section: Solar Storms Of September 2017 and Their Effects At Earth Anmentioning

confidence: 99%

Effects of the 10 September 2017 Solar Flare on the Density and Composition of the Thermosphere of Mars

et al. 2020

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The effects of solar flares on the upper atmosphere of Mars are large but poorly constrained by observations. These effects are an important aspect of the response of Mars to space weather events and may also influence the escape of volatiles from Mars, particularly in the solar system's early history. Here we report the effects of the X8.2 flare on 10 September 2017 on the density and composition of the thermosphere of Mars. This analysis uses neutral number densities of He, O, N 2 , CO, Ar, and CO 2 from the MAVEN Neutral Gas and Ion Mass Spectrometer (NGIMS). From these observations, we investigate how the enhanced solar irradiance during the flare produced changes in the neutral upper atmosphere of Mars due to atmospheric heating and photochemistry. Flare-produced photochemical changes in the neutral thermosphere of Mars have been previously implied but not quantified. We find that at fixed altitudes, the number densities of all species barring He increase and the O/CO 2 ratio decreases by ∼15-45%, indicating thermal expansion. However, when viewed at fixed total number densities, the densities of CO 2 and Ar decrease, and the O/CO 2 ratio increases by up to a factor of ∼3. The photodissociation of CO 2 is one photochemical process that produces changes resembling those identified. The quantified changes will help to constrain the shifting chemical makeup of the upper atmosphere due to these impactful flare events and may aid modeling of flare behavior and the impact of flares on the evolution of the Martian climate.

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“…The overall trend follows observations from MAVEN/SWEA and also MAVEN/SEP‐FTO (Figure c). Ramstad et al () reported the first attempt to calibrate the IMA penetrating background counts with the MAVEN/SEP‐FTO data. In doing so, they found that the IMA background counts are due to >1 MeV SEP electrons and >20 MeV protons.…”

Section: Seps At Marsmentioning

confidence: 99%

Observations and Impacts of the 10 September 2017 Solar Events at Mars: An Overview and Synthesis of the Initial Results

Lee

Jakosky

Luhmann

et al. 2018

Geophysical Research Letters

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117

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On 10 September 2017, some of the strongest solar activity occurred in association with active region 12673 (AR2673), including an X‐class solar flare and a fast coronal mass ejection. Although AR2673 was not centrally facing Mars, the activity impacted the local space weather conditions at Mars. We give an overview of observations obtained from the Mars Atmosphere and Volatile EvolutioN, Mars Science Laboratory, and Mars Express missions. Numerical results from the Wang‐Sheeley‐Arge (WSA)‐Enlil‐cone model together with Earth/L1 and STEREO‐A observations are also presented to provide some heliospheric context. We discuss the initial results on the space weather impacts at Mars, which include heating of the upper atmosphere by solar flare emissions, flare‐related enhancements of ion and neutral densities, solar energetic particles impacting the atmosphere and surface, bright emissions of a diffuse (global) aurora, deeply penetrating interplanetary magnetic fields over the Martian dayside, and enhanced atmospheric escape rates.

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The September 2017 SEP Event in Context With the Current Solar Cycle: Mars Express ASPERA‐3/IMA and MAVEN/SEP Observations

Cited by 17 publications

References 12 publications

Variability of Precipitating Ion Fluxes During the September 2017 Event at Mars

Variability of Precipitating Ion Fluxes During the September 2017 Event at Mars

Effects of the 10 September 2017 Solar Flare on the Density and Composition of the Thermosphere of Mars

Observations and Impacts of the 10 September 2017 Solar Events at Mars: An Overview and Synthesis of the Initial Results

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