Exploring the Predictability of the High‐Energy Tail of MEE Precipitation Based on Solar Wind Properties

Salice, Josephine Alessandra; Nesse, H.; Babu, Eldho Midhun; Smith‐Johnsen, Christine; Richardson, I. G.

doi:10.1029/2022ja031194

Cited by 10 publications

(10 citation statements)

References 65 publications

(160 reference statements)

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“…(2022) suggested that the delay between relativistic electron fluxes and the plasma density n sw (or velocity V sw ) of solar wind is around 10 hr. Moreover, substorm injection and solar wind pressure can also regulate the fluxes of sub‐MeV electrons (Salice et al., 2023; Tyssoy et al., 2021). In this study, we use the time delay between the wave detection and the index measurement to modify the AE and P d indices.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Global Distribution of Relativistic Electron Precipitation and the Dependences on Substorm Injection and Solar Wind Ram Pressure: Long‐Term POES Observations

Chen,

Gao,

et al. 2023

JGR Space Physics

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Relativistic electron precipitation (REP) into the Earth's atmosphere is one of the fundamental mechanisms causing radiation belt electron flux dropout. It is important to know the preferred regions of REP events and the interplanetary and magnetospheric conditions under which the events take place. In this study of the POES relativistic electron data during 1998–2017, we have examined all REP events from L = 3–10 using an automatic algorithm. The REP events preferentially occur in MLT = 17–03 at L = 4–6.5, where the precipitation fluxes also peak. The monthly average REP event number is correlated with both monthly average AE (auroral electrojet index) and Pd (solar wind ram pressure) indices, so we separately investigate the spatial dependences of the events on one index by restricting the other one to a low level. The occurrence rate of REP events increases with both the AE* and the indices (where AE* and are time‐modified from the AE and Pd indices). During large AE* but low , the events occur mainly in the dusk sector (MLT = 17–22) near the plasmapause. For large but low AE* intervals, most of the events occur outside the plasmapause in the midnight sector (MLT = 23–03). Possible REP loss mechanisms are discussed based on our findings. Our study provides new insights into the distribution and dependences of REP in the Earth's magnetosphere.

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Section: Conclusion and Discussionmentioning

confidence: 99%

Global Distribution of Relativistic Electron Precipitation and the Dependences on Substorm Injection and Solar Wind Ram Pressure: Long‐Term POES Observations

Chen,

Gao,

et al. 2023

JGR Space Physics

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“…This is consistent with the increased intensification of wave‐particle interactions of both the chorus whistler mode and plasmaspheric hiss in geomagnetic disturbed periods. For >292 keV the maximum precipitating fluxes is delayed a day or two, owing to the time it takes to accelerate the electrons to the respective energies (Nesse Tyssøy et al., 2021; Salice et al., 2023) suggesting that it is partly a product of accelerated seed particles tens of keV electrons. In the following days, both the precipitation from the main radiation belt and the slot region subside.…”

Section: Discussionmentioning

confidence: 99%

Energetic Electron Precipitation During Slot Region Filling Events

Nesse,

Babu,

Salice

et al. 2023

JGR Space Physics

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The slot region marks the equatorward boundary of the energetic electron precipitation (EEP). There are, however, numerous reports where energetic electrons cross these boundaries and fill the slot region. The ensuing EEP will occur long after the geomagnetic activity subsides. This is a missing energy input in current EEP estimates scaled by geomagnetic indices. This study explores the occurrence rate, duration, and local time dependence of slot region filling events using observations from the National Oceanic and Atmospheric Administration/Polar Orbiting Environmental Satellites over a full solar cycle from 2004 to 2014. The EEP flux estimates are based on the Medium Energy Proton Electron Detector 0° and 90° detectors and the theory of pitch angle diffusion by wave‐particle interaction. The occurrence rates of >43, >114, and >292 keV events are found to be strongly energy and solar cycle dependent. Higher energy events are more likely to be associated with Coronal Mass Ejections and stronger geomagnetic deflections compared to lower energy events. Solar wind speed, Bz, and Ey reveal a calm period before the events, potentially important for preconditioning the ensuing magnetospheric mass convection. The slot region reforms more efficiently closer to the plasmapause, which creates a double EEP band throughout the recovery period. The slot region EEP maximizes around noon throughout the afternoon/evening sector, consistent with pitch angle scattering from plasmaspheric hiss and lightning induced whistler mode waves. Concurrent with slot region filling events, the Michelson Interferometer for Passive Atmospheric Sounding/Envisat nitric oxide density show an increase at <55° corrected geomagnetic latitudes. This demonstrates the importance of including slot region EEP when assessing the EEP impact on the atmosphere.

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“…Additionally, by examining a subset of absolute E1 and E3 events with similar/overlapping >43 keV peak fluxes, we seek to gain a deeper understanding of the specific conditions associated with acceleration and precipitation of the high-energy tail. The >292 keV peak flux correlates with the >43 keV peak flux; however, for a specific >43 keV value, the corresponding >292 keV peak flux can vary by an order of magnitude (Salice et al, 2023). Hence, exploring the relative increase between >43 and >292 keV peak fluxes allows for further insight into the conditions favorable for generating a high-energy tail, independent of the initial >43 keV flux level and total energy flux.…”

Section: Methodsmentioning

confidence: 99%

“…The Medium Energy Proton and Electron Detectors (MEPED) aboard the Polar Operational Environmental Satellites (POES) and European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) MetOp have the advantage of observing within the bounce loss cone (BLC) at polar latitudes, with several operational satellites over multiple solar cycles. Nonetheless, due to instrumental challenges and different data handling within the community, parameterization of MEE leads to a large range of ionization and electron flux estimates (Nesse Tyssøy et al, 2022;Sinnhuber et al, 2022) and is currently a highly active field of research (Beharrell et al, 2015;van de Kamp et al, 2016;van de Kamp et al, 2018;Mironova et al, 2019;Pettit et al, 2019;Tyssøy et al, 2019;Duderstadt et al, 2021;Partamies et al, 2021;Tyssøy et al, 2021;Tyssøy et al, 2021;Babu et al, 2022;Nesse Tyssøy et al, 2022;Zúñiga López et al, 2022;Babu et al, 2023;Nesse et al, 2023;Salice et al, 2023). Other initiatives, such as the UARS satellite (Winningham et al, 1993) and the ELFIN twin CubeSats (Angelopoulos et al, 2023), have also monitored high-energy EEP within the BLC but not with the same coverage.…”

Section: Introductionmentioning

confidence: 99%

“…However, a further understanding of MEE and its properties is necessary to capture the variability during especially strong flux responses, not only when it comes to the absolute flux response but also its duration. Research has found that the high-energy tail of MEE behaves differently compared to lower energies regarding quantity, timing, and duration (Ødegaard et al, 2017;Salice et al, 2023). The significance of MEE precipitation on atmospheric chemistry, debated in various studies (Clilverd et al, 2009;Newnham et al, 2011;Sinnhuber et al, 2011;Daae et al, 2012;Sinnhuber et al, 2014;Kirkwood et al, 2015), stems partly from limited particle measurements and scarce NO observations in the polar atmosphere, and partly from the significantly lower fluxes compared to auroral precipitation.…”

Section: Introductionmentioning

confidence: 99%

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The high-energy tail of energetic electron precipitation: solar wind drivers and geomagnetic responses

Salice,

Nesse,

Partamies

et al. 2024

Front. Astron. Space Sci.

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Compositional NOx changes caused by energetic electron precipitation (EEP) at a specific altitude and those co-dependent on vertical transport are referred to as the EEP direct and indirect effect, respectively. The direct effect of EEP at lower mesospheric and upper stratospheric altitudes is linked to the high-energy tail of EEP (≳ 300 keV). The relative importance of this direct effect on NOx, ozone, and atmospheric dynamics remains unresolved due to inadequate particle measurements and scarcity of polar mesospheric NOx observations. An accurate parameterization of the high-energy tail of EEP is, therefore, crucial. This study utilizes EEP flux data from MEPED aboard the POES/Metop satellites from 2004–2014. Data from both hemispheres (55–70° N/S) are combined in daily flux estimates. 164 peaks above the 90th percentile of the ≳ 30 keV flux are identified. These peaks are categorized into absolute E1 and E3 events representing weak and strong ≳ 300 keV responses, respectively. A subset of absolute E1 and E3 events with similar ≳ 30 keV responses is termed overlapping events. Additionally, relative E1 and E3 events are determined by the relative strength of the ≳ 300 keV response, scaled by the initial ≳ 30 keV flux. A comparison between E1 and E3 events aims to identify solar wind and geomagnetic conditions leading to high-energy EEP responses and to gain insight into the conditions that generate a high-energy tail, independent of the initial ≳ 30 keV flux level. Superposed epoch analysis of mesospheric NO density from SOFIE confirms an observable direct impact on lower mesospheric chemistry associated with the absolute E3 events. A probability assessment based on absolute events identifies specific thresholds in the solar wind-magnetosphere coupling function (epsilon) and the geomagnetic indices Kp*10 and Dst, capable of determining the occurrence or exclusion of absolute E1 and E3 events. Elevated solar wind speeds persisting in the recovery phase of a deep Dst trough appear characteristic of overlapping and relative E3 events. This study provides insight into which parameters are important for accurately modeling the high-energy tail of EEP.

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Exploring the Predictability of the High‐Energy Tail of MEE Precipitation Based on Solar Wind Properties

Abstract: Energetic particle precipitation (EPP) causes chemical changes in the upper atmosphere (≳50 km), for example, by creating NO x and HO x gasses (e.g.

Cited by 10 publications

References 65 publications

Global Distribution of Relativistic Electron Precipitation and the Dependences on Substorm Injection and Solar Wind Ram Pressure: Long‐Term POES Observations

Global Distribution of Relativistic Electron Precipitation and the Dependences on Substorm Injection and Solar Wind Ram Pressure: Long‐Term POES Observations

Energetic Electron Precipitation During Slot Region Filling Events

The high-energy tail of energetic electron precipitation: solar wind drivers and geomagnetic responses

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