Auroral Research Articles

A comparative study of the blue comets C/1908 R1 (Morehouse) and C/2016 R2 (Pan-STARRS)

The long-period comet C/1908 R1 (Morehouse) is distinguished by its early spectroscopic tail photography, which uncovered notably intense emission bands of N2+ and CO+ similar to the unusual characteristics of the atypical blue comet C/2016 R2 (Pan-STARRS). To probe potential parallels with C/2016 R2 further, we revisited the historical spectroscopic plates of C/1908 R1 while leveraging the New Astrometric Reduction of Old Observations (NAROO) project's advanced sub-micrometric scanner. We first reviewed the intensity ratio method, followed by a comprehensive spectroscopic analysis of the original historical plates to determine the comet's composition. Our analysis also encompassed an evaluation of C/1908 R1's dynamic trajectory using an N-body integrator and a detailed examination of tail morphology records. Our findings suggest that C/1908 R1 experienced no significant close encounters as it crossed the inner Solar System, anchoring its origins directly in the Oort Cloud and allowing us to ascertain that this was its inaugural voyage near the Sun. We determined a N2+ CO+ ratio of $ along with a dust-poor composition, particularities it shares with C/2016 R2. Moreover, by synthesizing observations of the tail's structure over the three-month period of visibility, we uncovered a link between tail dislocation events and aurora borealis sightings on Earth. This association underscores the comet tail’s heightened sensitivity to solar wind fluctuations due to its volatile makeup. The comet C/1908 R1 (Morehouse) emerges as one of the most unaltered relics of our Solar System's formation, offering another instance of a C/2016 R2-analogous comet. This underscores the importance of preserving and reexamining historical astronomical datasets, not only for historical significance but as a critical resource for contemporary scientific advancement.

A Study of Onychoscopic Findings in Various Dermatological Disorders

Context: About 10% of all the dermatological conditions are comprised nail disorders. It is challenging for the dermatologists to diagnose nail disorders quickly without the help of invasive procedures. Aims: The aim of the study was to evaluate onychoscopic patterns associated with various nail disorders. Settings and Designs: Hospital-based cross-sectional observational study was conducted at a tertiary care teaching institute in Maharashtra, India from November 2019 to May 2021. Materials and Methods: One hundred and fifty patients, with a history and clinical presentation suggestive of nail disorders, were recruited in the study after confirming the clinical diagnosis. Patients having secondarily modified lesions were excluded. Dry as well as wet onychoscopy using polarized and nonpolarized modes was performed with the help of DermLite 4 dermoscope with an attached OnePlus 8T mobile phone camera to capture and save the dermoscopic images. Data were compiled and statistically analyzed using SPSS version 21.0. Statistical Analysis Used: Categorical variables were expressed in frequency and percentages. Data were entered in Microsoft Excel and analyzed using SPSS version 20. P value (using Z-test for proportions) was calculated wherever needed. Results: The majority of the patients were in the age group of 21–50 years with slight male preponderance. Overall most common onychoscopic findings studied in all the disorders were the nail plate alterations followed by chromonychia. The most common nail changes associated with connective tissue disorders were changes in the proximal nail fold capillaries along with changes in the curvature. The most common change observed in onychomycosis was chromonychia. Aurora borealis, spikes, and jagged edges of onycholytic plate with ruin pattern of hyperkeratosis were specific to onychomycosis. Inflammatory disorders of the nail unit (e.g., lichen planus and nail psoriasis) showed nail plate alterations with increased nail plate fragility. Conclusions: Some onychoscopic patterns are observed consistently with certain diseases, and these can be used for their diagnosis, hence, avoiding unnecessary biopsies, thus improving the patient outcome.

A New Proton‐Hydrogen‐Electron Transport Model for Simulating Optical Emissions From Proton Aurora and Comparison With Ground Observations

AbstractEnergetic proton precipitation from the magnetosphere plays an important role in the magnetosphere‐ionosphere‐thermosphere coupling and energy transfer. Proton precipitation causes hydrogen emissions, such as Hβ (486.1 nm), and also triggers the excitation of other emission lines such as the blue‐line (427.8 nm) and the green‐line (557.7 nm). In light of the growing availability of ground‐based proton auroral measurements in recent years, we revisit the proton auroral modeling in this study, with more focus on the application for interpreting ground observations. An accurate simulation of these optical emissions requires a comprehensive understanding of particle transport and collisions in the upper atmosphere, where the simultaneous consideration of precipitating protons, newly generated energetic hydrogen atoms, and secondary electrons is critical. For this purpose, we couple a 3D Monte‐Carlo proton transport model and an electron transport model. The integrated model framework can compute the emission rates of most major auroral emission lines/bands resulting from proton precipitation, along with self‐consistent calculation of the ionospheric electron density variations. The model results show improved agreement with ground optical observations in terms of the Hβ yield and the green‐to‐Hβ ratio compared to previous model studies. Our new model is a valuable tool for quantifying excitation and ionization due to proton aurora. It has the potential to leverage ground observations to infer precipitating conditions at high altitudes and even for studying magnetospheric activity.

Polar lights optimizer: Algorithm and applications in image segmentation and feature selection

This study introduces Polar Lights Optimization (PLO), an algorithm based on the aurora phenomenon or polar lights. The aurora is a unique natural spectacle that occurs when energetic particles from the solar wind converge at the Earth's poles, influenced by the geomagnetic field and the Earth's atmosphere. By analyzing the motion of high-energy particles and delving into the underlying principles of physics, we propose a unique model for mimicking particle motion. This model integrates gyration motion and aurora oval walk, with the former facilitating local exploitation, while the latter enabling global exploration. By synergistically combining these two strategies, the proposed PLO achieves a balanced approach to local exploitation and global exploration. Additionally, a particle collision strategy is introduced to enhance the efficiency of escaping local optima. To evaluate the performance of PLO, a qualitative analysis experiment is designed to assess its ability to explore the problem space and search for solutions. PLO is compared against 9 classic algorithms and 8 high-performance algorithms using 30 benchmark functions from IEEE CEC2014. Furthermore, we compare and analyze PLO with the current state-of-the-art methods in the field, utilizing 12 benchmark functions from IEEE CEC2022. Subsequently, PLO is successfully applied to multi-threshold image segmentation and feature selection. Specifically, a PLO-based multi-threshold segmentation model and a binary PLO-based feature selection method are developed. The performance of PLO is also evaluated using 10 images from the Invasive Ductal Carcinoma (IDC) medical dataset, while the overall adaptability and accuracy of the feature selection model are tested using 8 medical datasets. These results affirm the emergence of PLO as an effective optimization tool ready for solving real-world problems, including those in the medical field. The source codes of PLO are available at https://aliasgharheidari.com/PLO.html and other websites.

Investigating Different Interpolation Methods for High-Accuracy VTEC Analysis in Ionospheric Research

The dynamic structure of the ionosphere and its changes play an important role in comprehending the natural cycle by linking earth sciences and space sciences. Ionosphere research includes a variety of fields like meteorology, radio wave reflection from the atmosphere, atmospheric anomaly detection, the impact on GNSS (Global Navigation Satellite Systems) signals, the exploration of earthquake precursors, and the formation of the northern lights. To gain further insight into this layer and to monitor variations in the total electron content (TEC), ionospheric maps are created using a variety of data sources, including satellite sensors, GNSS data, and ionosonde data. In these maps, data deficiencies are addressed by using interpolation methods. The objective of this study was to obtain high-accuracy VTEC (Vertical Total Electron Content) information to analyze TEC anomalies as precursors to earthquakes. We propose an innovative approach: employing alternative mathematical surfaces for VTEC calculations, leading to enhanced change analytical interpretation for anomaly detections. Within the scope of the application, the second-degree polynomial method, kriging (point and block model), the radial basis multiquadric, and the thin plate spline (TPS) methods were implemented as interpolation methods. During a 49-day period, the TEC values were computed at three different IGS stations, generating 1176 hourly grids for each interpolation model. As reference data, the ionospheric maps produced by the CODE (Center for Orbit Determination in Europe) Analysis Center were used. This study’s findings showed that, based on statistical values, the TPS model offered more accurate results than other methods. Additionally, it has been observed that the peak values in TEC calculations based on polynomial surfaces are eliminated in TPSs.

Scientists Captured the First Glimpse of a Rare Polar Aurora

Scientists Captured the First Glimpse of a Rare Polar Aurora

Multisensory Food Experiences in Northern Norway: An Exploratory Study.

Intrinsic and extrinsic sensory elements influence our food experiences. However, most research on extrinsic multisensory aspects of food has centered on WEIRD (White, Educated, Industrialized, Rich, and Democratic) urban participants. This study breaks from this trend by investigating multisensory food experiences in the context of Northern Norway, a region characterized by distinct seasonal shifts, harsh arctic weather, unique atmospheric phenomena (e.g., the midnight sun and northern lights), limited food growth opportunities, and a rich Sámi cultural heritage. Our aim was to unravel the formation and development of multisensory food experiences within a culturally and environmentally specific framework. Our exploratory research used participant observation and interviews, involving four researchers from diverse backgrounds who closely examined multisensory food experiences within four Northern Norwegian food-related tourism businesses, all infused with Sámi cultural elements. Our findings suggest four major themes: (1) Experience elements, involving elements associated with plants, animals, and inanimate objects; (2) Bipolar concepts, which refer to opposing dimensions where experience elements varied, notably in the interplay between Sámi and Norwegian traditions; (3) Sensory stories, which highlight the narratives, enriching the eating experience with context, such as tales of dining under the captivating northern lights; and (4) Values, which indicate guiding principles shaping these experiences on a broader scale, emphasizing support for local traditions and culture. Our main contribution is the presentation of a new contextual framework of multisensory food experiences, which can be applicable to studying food experiences in other contexts.

‘Northern lights’, the Welfare State Winter School, in Ulverston, February 1991

‘Northern lights’, the Welfare State Winter School, in Ulverston, February 1991

Characteristics of the Arctic nature in the perception of a child in the children's prose written by Semyon Tumat

Significant interest in the Arctic zone of Yakutia emerged at the end of the 20th century, when alluvial diamond deposits were discovered and began to be developed. The Arctic also has great prospects for hydrocarbons. At the present time there is a struggle for the development of natural resources of the Arctic, in this connection the relevance of the Arctic theme in Yakut literature as a whole increases. The Arctic is a mysterious, harsh northern land, which at the same time is very beautiful and dangerous. The land of White Silence fascinated and attracted explorers, travellers and romantics. Not only masters of words, but also artists, pedagogues, philosophers turned their eyes to the world of childhood as an integral part of people's life. Memories of childhood spent in the harsh northern land, of its courageous inhabitants - reindeer herders, hunters, fishermen - became the material for the literary works of the national writer of Yakutia, poet, prose writer Semyon Andreevich Popov-Tumat. In the works of the writer we get acquainted with the difficult life of the indigenous people of the North with their traditions, ways of life, with their feelings and dreams. We have analysed cycles of children's proses written by Semyon Tumat. In the stories of the writer contains a lot of cognitive information about the life of a simple man, a northerner, a master, transforming this harsh land and the amazing country of snow, endless sky, illuminated by the polar lights, the wonderful world of the Arctic. S. Tumat's prose does not glorify tenderness or mercy. In the works of the writer the most important themes are: the theme of childhood, upbringing, family, faith, willpower, the theme of nature, friendship and love. However, love for his native northern land, parents, the world of the Arctic appears in the works of a strong feeling, imprinted forever on the heroes. Semyon Andreevich approached to the disclosure of this issue individually; thinking over the style and details of the narrative, composition of the works, character and psychology of the heroes.

Conceptosphere of the basic concept “winter” in Yu. Shestalov’s lyrical poetry

The article presents a description of the conceptual sphere with the basic concept of “winter”, based on the lyrical poetry of the famous Mansi poet Yuvan Shestalov. The article develops philological regionalism as a current trend in literary criticism. Based on a conceptual analysis of two volumes of the poet’s poems from his complete works, the article suggests this conceptual sphere, proving the objective choice of the nearest periphery concepts by providing examples from the texts. The immediate periphery includes such concepts and their variants as “snow” (ice, blizzard, snowstorm, snow squall); “sleep”; “night” (stars, moon); “road” (skis, sleds, deer, movement, path); “fire” (bonfire, flame, hearth heat, hot tea, ray of sunshine, northern lights). The key conclusion is that winter for the lyrical hero is a time of discovery, a time of learning new things, moving forward, a time of love and creativity. This perception of winter and Ugra as a whole is at odds with the generally accepted perception of the northern region. We believe the presented analysis will help visualize the mental space of the peoples from the North and the “winter” concept functions in the poet’s lyrical poetry to better understand his individual works, at the same time evaluating his work as an integral, mobile and developing system.

Subsurface maturation in a saline aquifer CCS project development. Experience from the Northern Lights project, offshore Norway

The Northern Lights full-scale commercial CO 2 transport and storage project is open to multi-industry capture plants, in a business still under development. The geological sequestration concept of a sloping saline aquifer raised several subsurface challenges related to timeline, data availability and development constrains, which all affected the decision process. The subsurface focus on storage security required the different disciplines to perform adjustments to the established workflows available from the hydrocarbon industry. A risk management-focused approach, front-end loading and early emphasis on containment were paramount. Here we share the experience from the Northern Lights subsurface maturation process and highlight the crucial contribution from the different disciplines in a challenging new industry.

Ultrasensitive refractometric sensing via centimeter-scale metasurfaces with spatially gradient geometry generated by elastomer mechanical stretching

Plasmonic metasurfaces with gradient geometry are emerging two-dimensional optical elements with unique capabilities, such as manipulating light by imparting local, space-variant phase changes to an incident electromagnetic wave, eliminating the chromatic aberration. However, the costly and time-consuming fabrication process and the requirement of sophisticated optical characterization instruments restrict practical applications of plasmonic metasurfaces. Herein, we present a novel nanofabrication method to generate centimeter-scale metasurface with spatially gradient geometry over the whole metasurface by directional stretching of a trapezoid elastic carrier patterned with regular metallic nanostructures. This strategy eases the requirement of time-consuming and expensive lithographic techniques in conventional methods. The spatially gradient plasmonic metasurface exhibit variable transmittances under monochromatic and polar light illumination, resulting in grayscale patterns with different transmittance intensity distributions. An ultrahigh imaging-based sensitivity of 1495 pixel/refractive index unit (RIU) and a detection limit of 0.00068 RIU can be achieved based on the spatially gradient plasmonic metasurface, which is superior to the performance of the regular metasurface before stretching. This novel strategy is expected to be promising for fabrication of gradient metasurfaces to be employed in many fields of nanophotonics.

An Explainable Deep-learning Model of Proton Auroras on Mars

Proton auroras are widely observed on the dayside of Mars, identified as a significant intensity enhancement in the hydrogen Lyα (121.6 nm) emission at altitudes of ∼110 and 150 km. Solar wind protons penetrating as energetic neutral atoms into Mars’ thermosphere are thought to be primarily responsible for these auroras. Recent observations of spatially localized “patchy” proton auroras suggest a possible direct deposition of protons into Mars’ atmosphere during unstable solar wind conditions. Improving our understanding of proton auroras is therefore important for characterizing the interaction of the solar wind with Mars’ atmosphere. Here, we develop a first purely data-driven model of proton auroras using Mars Atmosphere and Volatile Evolution (MAVEN) in situ observations and limb scans of Lyα emissions between 2014 and 2022. We train an artificial neural network that reproduces individual Lyα intensities and relative Lyα peak intensity enhancements with Pearson correlations of ∼94% and ∼60% respectively for the test data, along with a faithful reconstruction of the shape of the observed altitude profiles of Lyα emission. By performing a Shapley Additive Explanations (SHAP) analysis, we find that solar zenith angle, solar longitude, CO2 atmosphere variability, solar wind speed, and temperature are the most important features for the modeled Lyα peak intensity enhancements. Additionally, we find that the modeled peak intensity enhancements are high for early local-time hours, particularly near polar latitudes, and the induced magnetic fields are weaker. Through SHAP analysis, we also identify the influence of biases in the training data and interdependences between the measurements used for the modeling, and an improvement of those aspects can significantly improve the performance and applicability of the ANN model.

EMM EMUS Observations of FUV Aurora on Mars: Dependence on Magnetic Topology, Local Time, and Season

AbstractWe present a comprehensive study of the nightside aurora phenomenon on Mars, utilizing observations from EMUS onboard Emirates Mars Mission. The oxygen emission at 130.4 nm is by far the brightest FUV auroral emission line observed at Mars. Our statistical analysis reveals geographic, solar zenith angle, local time, and seasonal dependencies of auroral occurrence. Higher occurrence of aurora is observed in regions of open magnetic topology, where crustal magnetic fields are either very weak or both strong and vertical. Aurora occurs more frequently closer to the terminator and is more likely on the dusk side than on the dawn side of the night hemisphere. A pronounced auroral feature appears close to midnight local times in the southern hemisphere, consistent with the spot of energetic electron fluxes previously identified in the Mars Global Surveyor data. This auroral spot is more frequent after midnight than before. Additionally, some regions on Mars are “aurora voids” where essentially no aurora occurs. Aurora exhibits a seasonal dependence, with a major enhancement near perihelion. Non–crustal field aurora additionally shows a secondary enhancement near Ls 30°. This seasonal variability is a combination of the variability in ionospheric photoelectrons and thermospheric atomic oxygen abundance. Auroral occurrence also shows an increase with the rise of Solar Cycle 25. The brightest auroral pixels are observed during space weather events such as Coronal Mass Ejections and Stream Interaction Regions. These observations not only shed light on where and when Martian aurora occurs, but also add to our understanding of Mars' magnetic environment and its interaction with the heliosphere.

Ion precipitation in the cusp for northward IMF and its relationship with magnetosheath flow

If the interplanetary magnetic field (IMF) has a northward component, a portion of the solar wind ions flowing in the high-latitude magnetosheath drastically alters the flow direction owing to lobe reconnection and follows the Earth's magnetic field lines toward the low-altitude cusp. Partly because of this folded path, the relationship between the speed of ion flow in the magnetosheath and the energy of the precipitating ions in the low-altitude cusp remains unclarified. Herein, we examined particle data from 11 years of observations by Defense Meteorological Satellite Program satellites to obtain 1990 cases through an automated event identification of the cusp. This corresponds to the largest number of cusp ion events reported to date for a stable northward IMF. The results revealed a positive correlation between the energy of the precipitating ions and the estimated flow speed in the magnetosheath, which answers the question that has remained unexplained for decades: why is the brightness of the cusp proton aurora more strongly correlated with the solar wind dynamic pressure than with the solar wind number density? We suggest additional energizations of the exhausted ions from lobe reconnection in the outflow region because of the turbulent electric field formed by the opposite flow of two ion populations—one in the tailward-directed magnetosheath flow and the other in the earthward-directed outflow jet.Graphical

How the Character of the Narrator Constructs a Narratee and an Implied Reader in Philip Pullman’s Northern Lights

How the Character of the Narrator Constructs a Narratee and an Implied Reader in Philip Pullman’s Northern Lights

62°S Witnesses the Transition of Boundary Layer Marine Aerosol Pattern Over the Southern Ocean (50°S–68°S, 63°E–150°E) During the Spring and Summer: Results From MARCUS (I)

AbstractThe Atmospheric Radiation Measurement Mobile Facility‐2 was installed onboard the research vessel Aurora Australis to measure aerosol properties during the 2017–2018 Measurement of Aerosols, Radiation, and CloUds over the pristine Southern ocean (MARCUS) Experiment, providing unique data on aerosols latitudinal and seasonal variation, including south of 60°S where previous observations are scarce. Data from a Cloud Condensation Nuclei (CCN) counter and Ultra‐High‐Sensitivity Aerosol Spectrometer show that both the number concentration (NCCN) and size distribution of CCN‐active aerosols, with diameters (D) between 60 nm < D < 1,000 nm are different over the North Southern Ocean (NSO) (50°S–60°S) and the South Southern Ocean (SSO) (62°S–68°S). The average NSO NCCN at 0.2% and 0.5% supersaturation were 28% and 49% less than that over the SSO. This increase of CCN over the SSO is caused by the increase of aerosols with 60 nm < D < 200 nm, consistent with calculations of Aerosol Scattering Angstrom Exponents derived from a nephelometer. Aerosol hygroscopicity growth factor measured by the Hygroscopic Tandem Differential Mobility Analyzer stayed close to 1.41 for aerosols with 50 nm < D < 250 nm over the SSO, but increased from 1.30 to 1.67 over the NSO, indicating different chemical compositions. Both CCN and Ice Nucleating Particles (INPs) showed a stronger variation with season than with latitude. The variation of heat‐labile and presumably proteinacous INPs suggests an increase of ice nucleating‐active microbes in summer.

The northern lights go south

The northern lights go south

Russian Emigrant Publishing House “Northern Lights” in Sweden (1920—1923): History and Significance

The “peripheral” status of the Russian emigration community in Sweden is due to the geographical location of the country and the absence of major publishing centers. The most fruitful period for the Russian Abroad in Sweden was the first half of the 1920s. At that time, the publishing enterprise “Northern Lights”, founded by I.A. Lundel and E.A. Lyatsky, was operating in Stockholm. During 1920—1923 the organization published about two dozen editions. These were mainly fiction, entertainment, popular science and practical books. A study of the external and internal conditions of the book market showed that it was E.A. Lyatsky who predetermined the short-term success of the organization and its further fate. The publishing house was closed down as unprofitable due to its reliance on expensive quality editions, unprofitable sales logistics and unfulfilled co-operation with Soviet Russia. Professor E.A. Lyatsky repeatedly tried to save “Northern Lights”, even to the point of moving the organization to Czechoslovakia. Nevertheless, having given his enterprise a name and built up a reputation, he did not preserve the repertoire, staff and internal culture. This project was important for E.A. Lyatsky, but only a stage in his humanitarian and informational struggle against Bolshevism. It is on the example of “Northern Lights” and especially the personality of its founder that the mission, values and political orientation of the Russian emigration as a whole can be clearly traced. It is important to comprehensively evaluate this historical experience in the context of the development of modern Russia.

Cytokine measurement using a multiplex technique with spectral flow cytometry: application in the study of the immunobiology of ascariasis

To quantify the production of Th1/Th2/Th17 cytokines induced by Ascaris lumbricoides antigens in peripheral blood mononuclear cells (PBMCs) using a multiplex technique. PBMCs were cultured from individuals with mild A. lumbricoides infection (n = 20) and uninfected individuals (n = 21) and stimulated with A. lumbricoides extract (ExtAscaris), a mix of anti-CD2/CD3/CD28 (CDmix) as a positive control, and only medium (negative control). Cytokines in the supernatants were measured using the BD™ Cytometric Bead Array Human Th1/Th2/Th17 kit, to identify IFN-γ, TNF, IL-10, IL-6, IL-4, IL-2, and IL-17A. Readings were taken on a spectral cytometer (Northern Lights, Cytek, USA), and analysis was performed using R software with packages "tidyverse," "beadplexr," "flowCore," and "arsenal." Cytokine concentrations were calculated using a 5-parameter logistic curve. The t-test was used to compare cases and controls, and statistical significance was set at p < 0.05. The study was approved by the Ethics Committee of the University of Cartagena and the participants provided informed consent. This study was financially supported by the Colombian Sistema General de Regalías under the BPIN2020000100405 - BPIN2020000100364. Efficient fluorescence intensity extraction for each cytokine was achieved using detection channel R8 and the "mclust" clustering model (Figure 1). No significant differences were found in the levels of the seven cytokines between cases and controls (Figure 2). Although the IFN-γ response to ExtAscaris was higher in cases than in controls (252.5 ng/mL vs. 173.1 ng/mL), the difference was not significant. IL-17A (detection limit: 18.9 pg/mL) was more detectable in cases than controls (5 cases, 23% vs. 2 controls, 9.5%). IL-4 was only detected in the supernatants from CDmix-stimulated cultures but not with the Ascaris extract (Figure 2). The multiplex technique using spectral flow cytometry combined with open-source software analysis proved applicable for quantifying cytokines induced by A. lumbricoides antigens in PBMCs. However, a more sensitive method is needed to evaluate IL-4 response in the context of ascariasis. The results did not reveal significant differences in cytokine production between cases and controls for the evaluated stimuli.