On the influence of energetic electron precipitation on the water cluster ion population in the upper D-region

Energetic electron precipitation (EEP) ionizes the Earth's atmosphere and leads to production of nitric oxide (NO) throughout the polar Mesosphere and Lower Thermosphere (MLT). In this study we investigate the direct and indirect NO response to the EEP using the Whole Atmosphere Community Climate Model (WACCM) version 6. In comparison to observations from SOFIE / AIM (Solar Occultation For Ice Experiment / Aeronomy of Ice in the Mesosphere), we find that EEP production of NO in the D-region is well simulated when both medium energy electron precipitation and negative and cluster ion chemistry are included in the model. However, the main EEP production of NO occurs in the E-region, and there the observed and modeled production differ. This discrepancy impacts also the D-region due to downward transport of long lived NO. The transport across the mesopause is seasonally dependent, and WACCM&#8217;s underestimate of D-region NO is highest during winter when downwelling from above is strong. The drivers of this transport are further investigated by a sensitivity study of WACCM&#8217;s gravity wave forcing.

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The role of EEP forcing and background dynamics on the seasonal NO variability in the MLT region

10.5194/egusphere-egu2020-4946 ◽

2020 ◽

Author(s):

Christine Smith-Johnsen ◽

Hilde Nesse Tyssøy ◽

Daniel Marsh ◽

Anne Smith

Keyword(s):

Climate Model ◽

Energetic Electron ◽

Eddy Diffusion ◽

Electron Precipitation ◽

Ion Chemistry ◽

D Region ◽

E Region ◽

Cluster Ion ◽

Mlt Region

<a name="docs-internal-guid-803d1a38-7fff-fefe-52f7-d0a055a4547b"></a><a name="docs-internal-guid-b8d76d48-7fff-149a-6440-413c0de833ae"></a> Energetic electron precipitation (EEP) ionizes the Earth's atmosphere and leads to production of nitric oxide (NO) from 50 to 150 km altitude. In this study we investigate the direct and indirect NO response to EEP using the Whole Atmosphere Community Climate Model (WACCM). In comparison to observations from SOFIE / AIM (Solar Occultation For Ice Experiment / Aeronomy of Ice in the Mesosphere), we find that EEP production of NO in the D-region is well simulated when both medium energy electron precipitation and negative and cluster ion chemistry is included in the model. However, the main EEP production of NO occurs in the E-region, and there the observed and modeled production differ. This discrepancy impacts also the D-region, and is seasonally dependent with the highest underestimate of D-region NO occuring during winter. The modeled transport across the mesopause during winter is generally weak, but strengthens with increased gravity wave activity. Increased eddy diffusion, increases NO at all altitudes through the polar MLT region

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Energetic electron precipitation as a source of ionization in the night-time D-region over the mid-latitude rocket range, South Uist

Journal of Atmospheric and Terrestrial Physics ◽

10.1016/0021-9169(73)90066-4 ◽

1973 ◽

Vol 35 (5) ◽

pp. 835-850 ◽

Cited By ~ 25

Author(s):

M.P Gough ◽

H.L Collin

Keyword(s):

Energetic Electron ◽

Electron Precipitation ◽

Night Time ◽

D Region

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D-region impact area of energetic electron precipitation during pulsating aurora

Annales Geophysicae ◽

10.5194/angeo-39-135-2021 ◽

2021 ◽

Vol 39 (1) ◽

pp. 135-149

Author(s):

Emma Bland ◽

Fasil Tesema ◽

Noora Partamies

Keyword(s):

Atmospheric Chemistry ◽

Energetic Electron ◽

Auroral Oval ◽

Electron Precipitation ◽

Syowa Station ◽

Magnetic Latitude ◽

D Region ◽

Impact Area ◽

Average Size ◽

The Impact

Abstract. A total of 10 radars from the Super Dual Auroral Radar Network (SuperDARN) in Antarctica were used to estimate the spatial area over which energetic electron precipitation (EEP) impacts the D-region ionosphere during pulsating aurora (PsA) events. We use an all-sky camera (ASC) located at Syowa Station to confirm the presence of optical PsAs, and then we use the SuperDARN radars to detect high frequency (HF) radio attenuation caused by enhanced ionisation in the D-region ionosphere. The HF radio attenuation was identified visually by examining quick-look plots of the background HF radio noise and backscatter power from each radar. The EEP impact area was determined for 74 PsA events. Approximately one-third of these events have an EEP impact area that covers at least 12∘ of magnetic latitude, and three-quarters cover at least 4∘ of magnetic latitude. At the equatorward edge of the auroral oval, 44 % of events have a magnetic local time extent of at least 7 h, but this reduces to 17 % at the poleward edge. We use these results to estimate the average size of the EEP impact area during PsAs, which could be used as a model input for determining the impact of PsA-related EEP on the atmospheric chemistry.

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Strong localized variations of the low-altitude energetic electron fluxes in the evening sector near the plasmapause

Annales Geophysicae ◽

10.1007/s00585-997-0025-2 ◽

1998 ◽

Vol 16 (1) ◽

pp. 25-33 ◽

Cited By ~ 15

Author(s):

E. E. Titova ◽

T. A. Yahnina ◽

A. G. Yahnin ◽

B. B. Gvozdevsky ◽

A. A. Lyubchich ◽

...

Keyword(s):

Sharp Increase ◽

Electron Flux ◽

Particle Interaction ◽

Energetic Electron ◽

Recovery Phase ◽

Electron Precipitation ◽

Statistical Characteristics ◽

Evening Sector ◽

Proton Precipitation ◽

Low Altitude

Abstract. Specific type of energetic electron precipitation accompanied by a sharp increase in trapped energetic electron flux are found in the data obtained from low-altitude NOAA satellites. These strongly localized variations of the trapped and precipitated energetic electron flux have been observed in the evening sector near the plasmapause during recovery phase of magnetic storms. Statistical characteristics of these structures as well as the results of comparison with proton precipitation are described. We demonstrate the spatial coincidence of localized electron precipitation with cold plasma gradient and whistler wave intensification measured on board the DE-1 and Aureol-3 satellites. A simultaneous localized sharp increase in both trapped and precipitating electron flux could be a result of significant pitch-angle isotropization of drifting electrons due to their interaction via cyclotron instability with the region of sharp increase in background plasma density.Key words. Ionosphere (particle precipitation; wave-particle interaction) Magnetospheric Physics (plasmasphere)

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