Rowan Dayton-Oxland

We present NORVIS (NORdlys Versatile Imaging Spectrograph), a portable broadband imaging spectrograph developed for ground-based auroral observations. Based on the Star'Ex optical concept, NORVIS is optimized for auroral emissions and covers approximately 380–860 nm in a single acquisition at a moderate spectral resolution of 1.2 nm FWHM. The instrument combines auroral spectroscopy, wide-field context imaging, field operation, automated spectral reduction, and centralized data archiving within a researcher-citizen science framework. First observations were obtained during a campaign at Skibotn Observatory, Norway, in February 2026, during which approximately 1200 spectra were acquired and reduced over three observing nights, with typical exposure times of 30 s. These observations demonstrate the simultaneous detection of key auroral emissions, including the N2+ 1NG bands at 391.4 and 427.8 nm and the [O I] emissions at 557.7 and 630.0/636.4 nm, while also providing access to the Hα region and to O I emissions at 777.4 and 844.6 nm. Representative observations illustrate the potential of NORVIS for emission-ratio diagnostics and geometry-aware interpretation of auroral structures. NORVIS is intended to form the basis of a distributed observing network, with coordinated deployments planned in Kiruna, Skibotn, Svalbard, and northern Finland, followed by permanent installations at Kiruna, Skibotn, the Kjell Henriksen Observatory in Svalbard, and Nyrölä.

Fragmented aurora-like emissions (fragments) are small-scale green E-region structures that have previously been reported mainly from high-latitude locations near the poleward auroral oval boundary. Here we present a global citizen-science dataset of 26 fragment observations from 2017 to 2025, collected through an international citizen-science campaign via the Skywarden platform. The observations span magnetic latitudes from approximately 53 to 76°, a wide range of magnetic local times and activity levels, both hemispheres, and diverse auroral conditions. The dataset substantially extends the observational record of fragments beyond previously reported high-latitude regions. Both isolated fragments (type I) and the quasi-periodic wave-like fragments (type II) are represented in this broader geographical context. To assess fragment locations relative to the auroral oval, three case studies combining satellite observations with ground-based auroral images were analysed in detail. These demonstrate that fragments occur poleward of the oval in Antarctica, equatorward of the oval in Manitoba, and within the oval near the diffuse-discrete boundary in Iceland. Together, the global dataset and case studies show that fragments occur across a much broader range of auroral and geomagnetic conditions and oval positions than previously documented. The results demonstrate the scientific value of citizen-science observations for studying short-lived and localised auroral phenomena.

Fragmented aurora-like emissions (fragments) are small-scale green E-region structures that have previously been reported mainly from high-latitude locations near the poleward auroral oval boundary. Here we present a global citizen-science dataset of 26 fragment observations from 2017 to 2025, collected through an international citizen-science campaign via the Skywarden platform. The observations span magnetic latitudes from approximately 53 to 76°, a wide range of magnetic local times and activity levels, both hemispheres, and diverse auroral conditions. The dataset substantially extends the observational record of fragments beyond previously reported high-latitude regions. Both isolated fragments (type I) and the quasi-periodic wave-like fragments (type II) are represented in this broader geographical context. To assess fragment locations relative to the auroral oval, three case studies combining satellite observations with ground-based auroral images were analysed in detail. These demonstrate that fragments occur poleward of the oval in Antarctica, equatorward of the oval in Manitoba, and within the oval near the diffuse-discrete boundary in Iceland. Together, the global dataset and case studies show that fragments occur across a much broader range of auroral and geomagnetic conditions and oval positions than previously documented. The results demonstrate the scientific value of citizen-science observations for studying short-lived and localised auroral phenomena.

Fragmented aurora-like emissions (fragments) are small-scale green E-region structures that have previously been reported mainly from high-latitude locations near the poleward auroral oval boundary. Here we present a global citizen-science dataset of 26 fragment observations from 2017 to 2025, collected through an international citizen-science campaign via the Skywarden platform. The observations span magnetic latitudes from approximately 53 to 76°, a wide range of magnetic local times and activity levels, both hemispheres, and diverse auroral conditions. The dataset substantially extends the observational record of fragments beyond previously reported high-latitude regions. Both isolated fragments (type I) and the quasi-periodic wave-like fragments (type II) are represented in this broader geographical context. To assess fragment locations relative to the auroral oval, three case studies combining satellite observations with ground-based auroral images were analysed in detail. These demonstrate that fragments occur poleward of the oval in Antarctica, equatorward of the oval in Manitoba, and within the oval near the diffuse-discrete boundary in Iceland. Together, the global dataset and case studies show that fragments occur across a much broader range of auroral and geomagnetic conditions and oval positions than previously documented. The results demonstrate the scientific value of citizen-science observations for studying short-lived and localised auroral phenomena.

Fragmented aurora-like emissions (fragments) are small-scale green E-region structures that have previously been reported mainly from high-latitude locations near the poleward auroral oval boundary. Here we present a global citizen-science dataset of 26 fragment observations from 2017 to 2025, collected through an international citizen-science campaign via the Skywarden platform. The observations span magnetic latitudes from approximately 53 to 76°, a wide range of magnetic local times and activity levels, both hemispheres, and diverse auroral conditions. The dataset substantially extends the observational record of fragments beyond previously reported high-latitude regions. Both isolated fragments (type I) and the quasi-periodic wave-like fragments (type II) are represented in this broader geographical context. To assess fragment locations relative to the auroral oval, three case studies combining satellite observations with ground-based auroral images were analysed in detail. These demonstrate that fragments occur poleward of the oval in Antarctica, equatorward of the oval in Manitoba, and within the oval near the diffuse-discrete boundary in Iceland. Together, the global dataset and case studies show that fragments occur across a much broader range of auroral and geomagnetic conditions and oval positions than previously documented. The results demonstrate the scientific value of citizen-science observations for studying short-lived and localised auroral phenomena.

We investigate the origin of the continuum emissions observed in the poleward boundary dayside aurora discovered in Partamies et al. 2025, known as GHOST, and propose that they arise from highly excited, hot N₂. Using spectral modelling and fits to ground-based measurements of high-resolution GHOST spectra, we demonstrate that vibrationally and rotationally excited N₂ and N₂⁺ can reproduce the observed structured continuum without requiring emission from NO. Spectral fitting indicates that GHOST events coincide with extreme ion heating and high neutral temperatures. Background conditions from additional events indicate that strong ionospheric flows are typically present, which can help to provide the necessary energy input for producing hot neutral and ionised N₂. Proton aurora observations and EISCAT incoherent scatter radar measurements of ionospheric plasma parameters indicate that two of our three events are located in the cusp. These results suggest that the combination of strong flow, heating, particle precipitation, and cusp conditions produce thermally excited N₂ populations which can account for the continuum spectrum of GHOST.

We investigate the origin of the continuum emissions observed in the poleward boundary dayside aurora discovered in Partamies et al. 2025, known as GHOST, and propose that they arise from highly excited, hot N₂. Using spectral modelling and fits to ground-based measurements of high-resolution GHOST spectra, we demonstrate that vibrationally and rotationally excited N₂ and N₂⁺ can reproduce the observed structured continuum without requiring emission from NO. Spectral fitting indicates that GHOST events coincide with extreme ion heating and high neutral temperatures. Background conditions from additional events indicate that strong ionospheric flows are typically present, which can help to provide the necessary energy input for producing hot neutral and ionised N₂. Proton aurora observations and EISCAT incoherent scatter radar measurements of ionospheric plasma parameters indicate that two of our three events are located in the cusp. These results suggest that the combination of strong flow, heating, particle precipitation, and cusp conditions produce thermally excited N₂ populations which can account for the continuum spectrum of GHOST.

Fragmented aurora-like emissions (fragments) are small-scale green E-region structures that have previously been reported mainly from high-latitude locations near the poleward auroral oval boundary. Here we present a global citizen-science dataset of 26 fragment observations from 2017 to 2025, collected through an international citizen-science campaign via the Skywarden platform. The observations span magnetic latitudes from approximately 53 to 76°, a wide range of magnetic local times and activity levels, both hemispheres, and diverse auroral conditions. The dataset substantially extends the observational record of fragments beyond previously reported high-latitude regions. Both isolated fragments (type I) and the quasi-periodic wave-like fragments (type II) are represented in this broader geographical context. To assess fragment locations relative to the auroral oval, three case studies combining satellite observations with ground-based auroral images were analysed in detail. These demonstrate that fragments occur poleward of the oval in Antarctica, equatorward of the oval in Manitoba, and within the oval near the diffuse-discrete boundary in Iceland. Together, the global dataset and case studies show that fragments occur across a much broader range of auroral and geomagnetic conditions and oval positions than previously documented. The results demonstrate the scientific value of citizen-science observations for studying short-lived and localised auroral phenomena.

We investigate the origin of the continuum emissions observed in the poleward boundary dayside aurora discovered in Partamies et al. 2025, known as GHOST, and propose that they arise from highly excited, hot N₂. Using spectral modelling and fits to ground-based measurements of high-resolution GHOST spectra, we demonstrate that vibrationally and rotationally excited N₂ and N₂⁺ can reproduce the observed structured continuum without requiring emission from NO. Spectral fitting indicates that GHOST events coincide with extreme ion heating and high neutral temperatures. Background conditions from additional events indicate that strong ionospheric flows are typically present, which can help to provide the necessary energy input for producing hot neutral and ionised N₂. Proton aurora observations and EISCAT incoherent scatter radar measurements of ionospheric plasma parameters indicate that two of our three events are located in the cusp. These results suggest that the combination of strong flow, heating, particle precipitation, and cusp conditions produce thermally excited N₂ populations which can account for the continuum spectrum of GHOST.

We investigate the origin of the continuum emissions observed in the poleward boundary dayside aurora discovered in Partamies et al. 2025, known as GHOST, and propose that they arise from highly excited, hot N₂. Using spectral modelling and fits to ground-based measurements of high-resolution GHOST spectra, we demonstrate that vibrationally and rotationally excited N₂ and N₂⁺ can reproduce the observed structured continuum without requiring emission from NO. Spectral fitting indicates that GHOST events coincide with extreme ion heating and high neutral temperatures. Background conditions from additional events indicate that strong ionospheric flows are typically present, which can help to provide the necessary energy input for producing hot neutral and ionised N₂. Proton aurora observations and EISCAT incoherent scatter radar measurements of ionospheric plasma parameters indicate that two of our three events are located in the cusp. These results suggest that the combination of strong flow, heating, particle precipitation, and cusp conditions produce thermally excited N₂ populations which can account for the continuum spectrum of GHOST.