Key elements of auroral substorm development and their relationship to recent observations of detached sub-auroral phenomena including STEVE-like emissions

Henderson, M. G.

doi:10.1016/j.jastp.2021.105600

Cited by 6 publications

(8 citation statements)

References 107 publications

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“…Energetic ions also heat ambient cold plasma (plasmasphere), and heated thermal electrons are believed to cause SAR arcs (Inaba et al., 2021). Proton aurora occurs near the meridian of intensifications in the auroral oval (streamers) (Henderson, 2021; Montbriand, 1971; Nishimura et al., 2014). SAR arcs detach from the auroral oval during substorms (Oyama et al., 2020; Takagi et al., 2018)…”

Section: Introductionmentioning

confidence: 99%

“…Energetic ions also heat ambient cold plasma (plasmasphere), and heated thermal electrons are believed to cause SAR arcs (Inaba et al, 2021). Proton aurora occurs near the meridian of intensifications in the auroral oval (streamers) (Henderson, 2021;Montbriand, 1971;Nishimura et al, 2014). SAR arcs detach from the auroral oval during substorms (Oyama et al, 2020;Takagi et al, 2018) Although both proton aurora and SAR arcs are related to ion injections to the inner magnetosphere, proton aurora and SAR arcs have been investigated separately, and to our knowledge, there has been no report about the relation between proton aurora and SAR arcs.…”

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confidence: 99%

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Interaction Between Proton Aurora and Stable Auroral Red Arcs Unveiled by Citizen Scientist Photographs

Nishimura

Bruus

Karvinen³

et al. 2022

JGR Space Physics

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Recently, a growing number of citizen scientists post photographs of the night sky, and they have made important contributions to shed light on upper atmospheric emissions that were little known among scientists. Citizen scientists brought Strong Thermal Emission Velocity Enhancement (STEVE) (MacDonald et al., 2018) to scientists' attention, and their photographs were an essential piece for recognize its existence and distinction from previously known types of emissions in the upper atmosphere. Dunes (Palmroth et al., 2020) are another discovery of upper-atmospheric emissions that was achieved by citizen scientist photographs. The present work was also motivated by citizen scientist photographs at subauroral latitudes in three nights. Observations indicate that the optical emissions resemble proton aurora and stable auroral red (SAR) arcs, but interestingly, the emissions show a dynamic interplay between the two types of phenomena that to our knowledge has never been reported.Proton aurora is caused by energetic proton precipitation from the ring current in the inner magnetosphere (Egeland & Burke, 2019). Proton aurora in terms of ground-based observations often refers to H β (486.1 nm) emissions, but proton precipitation also creates secondary electrons, whose collision with neutrals emits green (557.7 nm) light. The green emission is much brighter than the H β line, and proton aurora is recognized as green diffuse aurora in naked eyes (Ono et al., 1987). Proton aurora occasionally includes red (630.0 nm) emissions (Lummerzheim et al., 2001;Sakaguchi et al., 2012), and secondary electrons are also considered as the source of the red color in proton aurora.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Interaction Between Proton Aurora and Stable Auroral Red Arcs Unveiled by Citizen Scientist Photographs

Nishimura

Bruus

Karvinen³

et al. 2022

JGR Space Physics

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“…Streamers are believed to be the ionospheric signature of BBFs in the nightside plasma sheet [Lyons et al, 1999;Henderson et al 1998] and a wedge-type current system, where streamers mark upward FACs on the duskward edge of BBFs [Sergeev et al, 2004]. They can develop into large scale omega bands (folded auroral arc moving eastwards) and auroral torches (features that form when one of the legs of the omega extends dramatically towards the poleward active arc system), or they could be absorbed by a pre-existing auroral arc at the equatorward boundary [Henderson, 2021].…”

Section: The Science Casementioning

confidence: 99%

“…This process mass-loads the earthward side of the magnetopause, thereby affecting the reconnection rate and the accompanying high-latitude convection electric field [Ouellette et al, 2016]. It has been hypothesized that the intermixing of hot plasma sheet and cold plasmaspheric populations, due to SAPS driven instabilities, leads to both the observed subauroral emissions and also provides a source of cold plasma on open drift paths that can feed the recently discovered long-lived drainage plumes [Henderson et al, 2021]. This interplay associated with the plume has a global impact on plasma density redistribution.…”

Section: The Science Casementioning

confidence: 99%

PARAGON mission concept: Seeing the Global Geospace in Mesoscale Resolution

Gkioulidou,

Gabrielse,

DeMajistre

et al. 2023

Bulletin of the AAS

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In this paper we present PARAGON, a mission concept that provides predictive understanding of geomagnetic disturbances at systems level, by connecting global evolution to mesoscale dynamics and kinetic-scale effects. PARAGON introduces a paradigm shift in the way we observe geospace by utilizing coordinated: i) unprecedented spatial and temporal resolution imaging of the ring current, near-Earth plasma sheet, aurora, and plasmasphere and ii) in-situ plasma, energetic particles and magnetic field measurements, from different platforms, in order to discover, quantify and understand the global impact of mesoscale processes in the development of major geomagnetic disturbances. Since the beginning of the space age, we have ventured extensively into Earth's immediate surroundings, and have learned how geospace is a coupled system of systems, including the magnetosphere, the ionosphere and the upper atmosphere in which the ionosphere is embedded. Just like terrestrial weather disturbances, such as cyclones, evolve as a collection of processes at different spatial and temporal scales in the atmosphere, so too do geomagnetic storms transfer energy, mass, and momentum throughout geospace at local, mesoscale, and global scales. Multiple missions over the years have targeted either the local or global nature of geospace with in-situ probes or global imaging, respectively. However, understanding geomagnetic disturbances to the level of predictability remains elusive, because we still do not understand the bridge between the local and global geospace, that is, the mesoscale (1000 km to few R E in the magnetotail, ~10s-100s km in the ionosphere) processes and their global implications. PARAGON will determine under what conditions mesoscale processes in the coupled Magnetosphere-Ionosphere (M-I) system become geoeffective, by observing the global system in mesoscale resolution. PARAGON addresses fundamental questions about mesoscale processes that are observed throughout the solar system, from the fast rotating magnetospheres of Jupiter and Saturn to the supra-arcade downflows in the eruptive solar flares. Earth's accessible space environment provides the perfect laboratory for these processes to be explored in detail. With the outstanding question of the global impact of mesoscale processes still being at the forefront of magnetospheric physics, and considering the technological advancements over the last decade, PARAGON can and should be of the highestpriority for implementation in the upcoming decade.

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“…Geomagnetic substorms are disturbances in the Earth's magnetosphere triggered by the release of stored energy in the magnetotail (Akasofu, 1964; McPherron, 1979). Although the major phenomena that occur during the auroral substorm are well‐established (e.g., Akasofu, 2017; Henderson, 2021, and references therein), the corresponding sequence of events in the magnetosphere remains hotly debated (e.g., Angelopoulos et al., 2008; Lui, 2003; Lui et al., 2008; Ohtani, 2001). The substorm has three phases: growth, expansion, and recovery.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Energetic Proton Parallel Pressure Anisotropy at Geosynchronous Altitudes: Potential Role in Triggering Substorm Expansion Phase Onset

Babu,

Mann,

Dimitrakoudis

et al. 2024

Geophysical Research Letters

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The sequence of events associated with the triggering of energy release during substorm expansion phase onset is still not well‐understood. Oberhagemann and Mann (2020b, https://doi.org/10.1029/2019gl085271) proposed a new substorm onset mechanism, where the transition toward parallel proton pressure anisotropy during tail stretching in the late growth phase could trigger a pressure anisotropic ballooning instability. Here we examine the evolution of energetic proton parallel pressure anisotropy at geosynchronous altitudes, seeking evidence in support of the proposed substorm onset mechanism. We use the Geostationary Operational Environment Satellite (GOES) proton flux and magnetometer data combined with substorm onset indicators derived from ground‐based magnetometers. Superposed epoch analysis of substorm onset times for 2014 using the isolated substorm list (Ohtani & Gjerloev, 2020, https://doi.org/10.1029/2020ja027902) clearly shows signatures of energetic proton parallel pressure anisotropy immediately before substorm onset, potentially supportive of the Oberhagemann and Mann theory.

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Key elements of auroral substorm development and their relationship to recent observations of detached sub-auroral phenomena including STEVE-like emissions

Cited by 6 publications

References 107 publications

Interaction Between Proton Aurora and Stable Auroral Red Arcs Unveiled by Citizen Scientist Photographs

Interaction Between Proton Aurora and Stable Auroral Red Arcs Unveiled by Citizen Scientist Photographs

PARAGON mission concept: Seeing the Global Geospace in Mesoscale Resolution

Evolution of Energetic Proton Parallel Pressure Anisotropy at Geosynchronous Altitudes: Potential Role in Triggering Substorm Expansion Phase Onset

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