Cosmic noise absorption signature of particle precipitation during interplanetary coronal mass ejection sheaths and ejecta

Kilpua, Emilia; Juusola, Liisa; Grandin, Maxime; Kero, Antti; Dubyagin, S.; Partamies, Noora; Osmane, Adnane; Kalliokoski, Milla; Raita, Tero; Asikainen, Timo; Palmroth, Minna

doi:10.5194/angeo-38-557-2020

Cited by 3 publications

(5 citation statements)

References 102 publications

(130 reference statements)

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“…This conclusion agrees well with earlier observations of the radiation belt dynamics, where a 1-3 day delay was found between the substorm activity and the maximum radiation belt response (Forsyth et al, 2016). As was further discussed by Kilpua et al (2020), the direct substorm injection to the ionosphere results in less intense precipitation than that driven by wave-particle interaction, which is in effect when the injected electrons are drifting into the morning sector after the injection. It was also concluded by Grandin et al (2017) that strong CNA is more likely to occur during a substorm event with a longer duration.…”

Section: Discussionsupporting

confidence: 92%

“…The CNA values during the substorms studied here peaked between 0.5 and 1.0 dB (Figure 4), which is between the longterm average CNA including the quiet times (CNA mainly below 0.5 dB, Kavanagh et al, 2004) and the absorption values related to geomagnetic storms driven by coronal mass ejection (CME) sub-structures, sheath and ejecta (CNA values typically around 1 dB, Kilpua et al, 2020). An earlier study on HSS-driven substorms reported CNA levels of 1-2 dB (Grandin et al, 2017).…”

Section: Discussionmentioning

confidence: 71%

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Electron precipitation characteristics during isolated, compound and multi-night substorm events

Partamies¹,

Tesema²,

Bland³

et al. 2020

Preprint

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Abstract. A set of 24 isolated, 46 compound and 36 multi-night substorm events from the years 2008–2013 have been analysed in this study. Isolated substorm events are defined as single expansion-recovery phase pairs, compound substorms consist of multiple phase pairs, and multi-night substorm events refer to recurring substorm activity on consecutive nights. Approximately 200 nights of substorm activity observed over the Fennoscandian Lapland have been analysed for their magnetic disturbance magnitude and the level of cosmic radio noise absorption. Substorm events were automatically detected from the local electrojet index data and visually categorised. We show that isolated substorms have limited lifetimes and spatial extents, as compared to the other substorm types. The average intensity (both in absorption and ground-magnetic deflection) of compound and multi-night substorm events is similar. For multi-night substorm events, the first night is rarely associated with the strongest absorption. Instead, the high-energy electron population needed to cause the strongest absorption builds up over 1–2 additional nights of substorm activity. The non-linear relationship between the absorption and the magnetic deflection at high and low activity conditions is also discussed. We further collect in-situ particle spectra for expansion and recovery phases to construct median precipitation fluxes at energies from 30 eV up to about 800 keV. In the expansion phases the bulk of the spectra shows a local maximum flux in the range of a few keV to 10 keV, while in the recovery phases higher fluxes are seen in the range of tens of keV to hundreds of keV. These findings are discussed in the light of earlier observations of substorm precipitation and their atmospheric effects.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 71%

Electron precipitation characteristics during isolated, compound and multi-night substorm events

Partamies¹,

Tesema²,

Bland³

et al. 2020

Preprint

Self Cite

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show abstract

“…A more direct estimate of the atmospheric impact area could be obtained by determining the spatial extent of the CNA, since this parameter is sensitive specifically to the particle precipitation energies associated with an atmospheric impact. Bland et al (2020) recently used the Super Dual Auroral Radar Network (Super-DARN, Lester, 2013) to estimate the spatial coverage of the particle precipitation impact area during pulsating aurora by studying the attenuation of 10-12 MHz radio noise in the Dregion ionosphere. They found that the atmospheric impact area extended over at least 4 • of magnetic latitude for 75 % of the PsA events studied, and 36 % of the events extended over at least 12 • of magnetic latitude.…”

Section: Discussionmentioning

confidence: 99%

Electron precipitation characteristics during isolated, compound, and multi-night substorm events

Partamies

Tesema

Bland³

et al. 2021

Ann. Geophys.

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Abstract. A set of 24 isolated, 46 compound, and 36 multi-night substorm events from the years 2008–2013 have been analysed in this study. Isolated substorm events are defined as single expansion–recovery phase pairs, compound substorms consist of multiple phase pairs, and multi-night substorm events refer to recurring substorm activity on consecutive nights. Approximately 200 nights of substorm activity observed over Fennoscandian Lapland have been analysed for their magnetic disturbance magnitude and the level of cosmic radio noise absorption. Substorm events were automatically detected from the local electrojet index data and visually categorized. We show that isolated substorms have limited lifetimes and spatial extents as compared to the other substorm types. The average intensity (both in absorption and ground-magnetic deflection) of compound and multi-night substorm events is similar. For multi-night substorm events, the first night is rarely associated with the strongest absorption. Instead, the high-energy electron population needed to cause the strongest absorption builds up over 1–2 additional nights of substorm activity. The non-linear relationship between the absorption and the magnetic deflection at high- and low-activity conditions is also discussed. We further collect in situ particle spectra for expansion and recovery phases to construct median precipitation fluxes at energies from 30 eV up to about 800 keV. In the expansion phases the bulk of the spectra show a local maximum flux in the range of a few keV to 10 keV, while in the recovery phases higher fluxes are seen in the range of tens of keV to hundreds of keV. These findings are discussed in the light of earlier observations of substorm precipitation and their atmospheric effects.

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“…Continuous monitoring of energetic particle precipitation by riometers allows long-term global studies, such as statistical behaviour of solar proton and electron precipitation impact regions in the atmosphere (e.g. Kilpua et al 2020;Heino et al 2019;Heino and Partamies 2020). The two-dimensional CNA distribution, in turn, facilitates more detailed spatial distribution studies of hard precipitation regions in comparison with other observations (e.g.…”

Section: Climatology Of the Ionospherementioning

confidence: 99%

“…Some of the recent studies are listed in the next section. Kilpua et al (2020) studied electron precipitation associated with the interplanetary coronal mass ejections (ICME), i.e. the coronal mass ejection observed close to the Sun (CME) when it moves in the interplanetary space.…”

Section: Climatology Of the Ionospherementioning

confidence: 99%

Review of Environmental Monitoring by Means of Radio Waves in the Polar Regions: From Atmosphere to Geospace

et al. 2022

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The Antarctic and Arctic regions are Earth's open windows to outer space. They provide unique opportunities for investigating the troposphere–thermosphere–ionosphere–plasmasphere system at high latitudes, which is not as well understood as the mid- and low-latitude regions mainly due to the paucity of experimental observations. In addition, different neutral and ionised atmospheric layers at high latitudes are much more variable compared to lower latitudes, and their variability is due to mechanisms not yet fully understood. Fortunately, in this new millennium the observing infrastructure in Antarctica and the Arctic has been growing, thus providing scientists with new opportunities to advance our knowledge on the polar atmosphere and geospace. This review shows that it is of paramount importance to perform integrated, multi-disciplinary research, making use of long-term multi-instrument observations combined with ad hoc measurement campaigns to improve our capability of investigating atmospheric dynamics in the polar regions from the troposphere up to the plasmasphere, as well as the coupling between atmospheric layers. Starting from the state of the art of understanding the polar atmosphere, our survey outlines the roadmap for enhancing scientific investigation of its physical mechanisms and dynamics through the full exploitation of the available infrastructures for radio-based environmental monitoring.

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Cosmic noise absorption signature of particle precipitation during interplanetary coronal mass ejection sheaths and ejecta

Cited by 3 publications

References 102 publications

Electron precipitation characteristics during isolated, compound and multi-night substorm events

Electron precipitation characteristics during isolated, compound and multi-night substorm events

Electron precipitation characteristics during isolated, compound, and multi-night substorm events

Review of Environmental Monitoring by Means of Radio Waves in the Polar Regions: From Atmosphere to Geospace

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