Oluwaseyi Emmanuel Jimoh, J. Lei, F. Huang, J. Zhong
In this study, the variations of topside ionospheric irregularities during 24 geomagnetic storms with Dst < -50 nT in 2015 were examined through an algorithm specifically designed to detect a significant level of ionospheric irregularities. The algorithm was developed through the use of several parameters derived from the topside total electron content (TEC) observations from GRACE, Swarm-C, and Swarm-B. The local time characteristics of the observed equatorial plasma irregularities (EPIs) were analyzed during different phases of the storms, within 30 S-30 N magnetic latitudes. By comparing its results with corresponding in-situ electron density data and the results of previous studies, the algorithm was found to be efficient. It was observed that the detected EPIs at different stages of the storm showed local time dependence. For instance, EPIs were observed during nighttimes, but took place in the daytime occasionally during the storm main phase. Furthermore, the percentage occurrence rates were most prominent during the main phase at the post-sunset sector within less than 6 hours of the storm onset. On the other hand, the occurrence rates became prominent in the postmidnight/morning sector during the recovery phase and even higher than observed in the post-sunset sector. Based on these findings it was concluded that the dominant driver of the enhanced EPIs during the post-midnight/daytime sector could be associated with disturbance dynamo electric fields.
{"title":"The Study of Topside Ionospheric Irregularities during Geomagnetic Storms in 2015","authors":"Oluwaseyi Emmanuel Jimoh, J. Lei, F. Huang, J. Zhong","doi":"10.1051/swsc/2022028","DOIUrl":"https://doi.org/10.1051/swsc/2022028","url":null,"abstract":"In this study, the variations of topside ionospheric irregularities during 24 geomagnetic storms with Dst < -50 nT in 2015 were examined through an algorithm specifically designed to detect a significant level of ionospheric irregularities. The algorithm was developed through the use of several parameters derived from the topside total electron content (TEC) observations from GRACE, Swarm-C, and Swarm-B. The local time characteristics of the observed equatorial plasma irregularities (EPIs) were analyzed during different phases of the storms, within 30 S-30 N magnetic latitudes. By comparing its results with corresponding in-situ electron density data and the results of previous studies, the algorithm was found to be efficient. It was observed that the detected EPIs at different stages of the storm showed local time dependence. For instance, EPIs were observed during nighttimes, but took place in the daytime occasionally during the storm main phase. Furthermore, the percentage occurrence rates were most prominent during the main phase at the post-sunset sector within less than 6 hours of the storm onset. On the other hand, the occurrence rates became prominent in the postmidnight/morning sector during the recovery phase and even higher than observed in the post-sunset sector. Based on these findings it was concluded that the dominant driver of the enhanced EPIs during the post-midnight/daytime sector could be associated with disturbance dynamo electric fields.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2022-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45070164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiawei Gao, M. Korte, S. Panovska, Z. Rong, Yong Wei
The geomagnetic field prevents energetic particles, such as galactic cosmic rays, from directly interacting with the Earth's atmosphere. The geomagnetic field is not static but constantly changing, and over the last 100,000 years several geomagnetic excursions occurred. During geomagnetic field excursions, the field strength is significantly decreased and the field morphology is strongly influenced by non-dipole components, and more cosmic ray particles can access the Earth's atmosphere. Paleomagnetic field models provide a global view of the long-term geomagnetic field evolution, however, with individual spatial and temporal resolution and uncertainties. Here, we reconstruct the geomagnetic shielding effect over the last 100,000 years by calculating the geomagnetic field cutoff rigidity using four global paleomagnetic field models, i.e., the GGF100k, GGFSS70, LSMOD.2, and CALS10k.2 model. We compare results for overlapping periods and find that the model selection is crucial to constrain the cutoff rigidity variation. However, all models indicate that the non-dipole components of the geomagnetic field are not negligible for estimating the long-term geomagnetic shielding effect. We provide a combined record of global cutoff rigidities using the best available model for individual time intervals. Our results provide the possibility to estimate the cosmogenic isotope production rate and cosmic radiation dose rate covering the last 100,000 years according to the best current knowledge about geomagnetic field evolution, and will be useful in further long-term solar activity and climate change reconstruction.
{"title":"Geomagnetic field shielding over the last one hundred thousand years","authors":"Jiawei Gao, M. Korte, S. Panovska, Z. Rong, Yong Wei","doi":"10.1051/swsc/2022027","DOIUrl":"https://doi.org/10.1051/swsc/2022027","url":null,"abstract":"The geomagnetic field prevents energetic particles, such as galactic cosmic rays, from directly interacting with the Earth's atmosphere. The geomagnetic field is not static but constantly changing, and over the last 100,000 years several geomagnetic excursions occurred. During geomagnetic field excursions, the field strength is significantly decreased and the field morphology is strongly influenced by non-dipole components, and more cosmic ray particles can access the Earth's atmosphere. Paleomagnetic field models provide a global view of the long-term geomagnetic field evolution, however, with individual spatial and temporal resolution and uncertainties. Here, we reconstruct the geomagnetic shielding effect over the last 100,000 years by calculating the geomagnetic field cutoff rigidity using four global paleomagnetic field models, i.e., the GGF100k, GGFSS70, LSMOD.2, and CALS10k.2 model. We compare results for overlapping periods and find that the model selection is crucial to constrain the cutoff rigidity variation. However, all models indicate that the non-dipole components of the geomagnetic field are not negligible for estimating the long-term geomagnetic shielding effect. We provide a combined record of global cutoff rigidities using the best available model for individual time intervals. Our results provide the possibility to estimate the cosmogenic isotope production rate and cosmic radiation dose rate covering the last 100,000 years according to the best current knowledge about geomagnetic field evolution, and will be useful in further long-term solar activity and climate change reconstruction.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49039375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Accurate forecasting of the solar wind has grown in importance as society becomes increasingly dependent on technology that is susceptible to space weather events. This work describes an inner boundary condition for ambient solar wind models based on tomography maps of the coronal plasma density gained from coronagraph observations, providing a novel alternative to magnetic extrapolations. The tomographical density maps provide a direct constraint of the coronal structure at heliocentric distances of 4 to 8 Rs, thus avoiding the need to model the complex non-radial lower corona. An empirical inverse relationship converts densities to solar wind velocities which are used as an inner boundary condition by the Heliospheric Upwind Extrapolation (HUXt) model to give ambient solar wind velocity at Earth. The dynamic time warping (DTW) algorithm is used to quantify the agreement between tomography/HUXt output and insitu data. An exhaustive search method is then used to adjust the lower boundary velocity range in order to optimize the model. Early results show a 40% decrease in mean absolute error between measured and modelled velocities compared to that of the coupled MAS/HUXt model. The use of density maps gained from tomography as an inner boundary constraint is thus a valid alternative to coronal magnetic models, and offers a significant advancement in the field given the availability of routine space-based coronagraph observations.
{"title":"An inner boundary condition for solar wind models based on coronal density","authors":"K. A. Bunting, H. Morgan","doi":"10.1051/swsc/2022026","DOIUrl":"https://doi.org/10.1051/swsc/2022026","url":null,"abstract":"Accurate forecasting of the solar wind has grown in importance as society becomes increasingly dependent on technology that is susceptible to space weather events. This work describes an inner boundary condition for ambient solar wind models based on tomography maps of the coronal plasma density gained from coronagraph observations, providing a novel alternative to magnetic extrapolations. The tomographical density maps provide a direct constraint of the coronal structure at heliocentric distances of 4 to 8 Rs, thus avoiding the need to model the complex non-radial lower corona. An empirical inverse relationship converts densities to solar wind velocities which are used as an inner boundary condition by the Heliospheric Upwind Extrapolation (HUXt) model to give ambient solar wind velocity at Earth. The dynamic time warping (DTW) algorithm is used to quantify the agreement between tomography/HUXt output and insitu data. An exhaustive search method is then used to adjust the lower boundary velocity range in order to optimize the model. Early results show a 40% decrease in mean absolute error between measured and modelled velocities compared to that of the coupled MAS/HUXt model. The use of density maps gained from tomography as an inner boundary constraint is thus a valid alternative to coronal magnetic models, and offers a significant advancement in the field given the availability of routine space-based coronagraph observations.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2022-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41681101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brett R. Carter, Gail Iles, Rehka Raju, A. Afful, R. Maj, T. Dao, M. Terkildsen, V. Lobzin, Z. Bouya, M. Parkinson, S. Le May, S. Choy, Paweł Hordyniec, Barbara Hordyniec, J. Currie, T. Skov, I. Peake
Space weather is a key component in the daily operation of many technological systems and applications; including large-scale power grids, high-frequency radio systems and satellite systems. As the international space sector continues to boom, accessible space weather products, tools and education are increasingly important to ensure that space actors (both old and new) are equipped with the knowledge of how space weather influences their activities and applications. At RMIT University, the initiative was taken to develop a Space Weather Prediction Laboratory exercise for students as part of its new offering of a Bachelor Degree in Space Science in 2020. This new Space Weather Prediction Lab exercise is offered as part of an undergraduate course on `Space Exploration', which has a diverse student in-take, including students with no background in physics; a key detail in the design of the Lab. The aims of the Space Weather Prediction Lab were to: (1) Provide a short and intense introduction to the near-Earth space environment and its impact on various human technologies; (2) Give students `hands-on' training in data analysis, interpretation and communication; and (3) Create an immersive space science experience for students that encourages learning, scientific transparency and teamwork. The format of the lab that was developed can be easily scaled in difficulty to suit the students' technical level, either by including more/less space weather datasets in the analysis or by analyzing more/less complicated space weather events. The details of the Space Weather Prediction Lab developed and taught at RMIT in 2020, in both face-to-face and online formats, are presented.
{"title":"RMIT University's Practical Space Weather Prediction Laboratory","authors":"Brett R. Carter, Gail Iles, Rehka Raju, A. Afful, R. Maj, T. Dao, M. Terkildsen, V. Lobzin, Z. Bouya, M. Parkinson, S. Le May, S. Choy, Paweł Hordyniec, Barbara Hordyniec, J. Currie, T. Skov, I. Peake","doi":"10.1051/swsc/2022025","DOIUrl":"https://doi.org/10.1051/swsc/2022025","url":null,"abstract":"Space weather is a key component in the daily operation of many technological systems and applications; including large-scale power grids, high-frequency radio systems and satellite systems. As the international space sector continues to boom, accessible space weather products, tools and education are increasingly important to ensure that space actors (both old and new) are equipped with the knowledge of how space weather influences their activities and applications.\u0000\u0000 \u0000\u0000At RMIT University, the initiative was taken to develop a Space Weather Prediction Laboratory exercise for students as part of its new offering of a Bachelor Degree in Space Science in 2020. This new Space Weather Prediction Lab exercise is offered as part of an undergraduate course on `Space Exploration', which has a diverse student in-take, including students with no background in physics; a key detail in the design of the Lab. The aims of the Space Weather Prediction Lab were to: (1) Provide a short and intense introduction to the near-Earth space environment and its impact on various human technologies; (2) Give students `hands-on' training in data analysis, interpretation and communication; and (3) Create an immersive space science experience for students that encourages learning, scientific transparency and teamwork. The format of the lab that was developed can be easily scaled in difficulty to suit the students' technical level, either by including more/less space weather datasets in the analysis or by analyzing more/less complicated space weather events. The details of the Space Weather Prediction Lab developed and taught at RMIT in 2020, in both face-to-face and online formats, are presented.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48509577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Leslie J Lamarche, Kshitija B Deshpande, Matthew D Zettergren
Small-scale ionospheric plasma structures can cause scintillation in radio signals passing through the ionosphere. The relationship between the scintillated signal and how plasma structuring develops is complex. We model the development of small-scale plasma structuring in and around an idealized polar cap patch observed by the Resolute Bay Incoherent Scatter Radars (RISR) with the Geospace Environment Model for Ion-Neutral Interactions (GEMINI). Then, we simulate a signal passing through the resulting small-scale structuring with the Satellite-beacon Ionospheric-scintillation Global Model of the upper Atmosphere (SIGMA) to predict the scintillation characteristics that will be observed by a ground receiver at different stages of instability development. Finally, we compare the predicted signal characteristics with actual observations of scintillation from ground receivers in the vicinity of Resolute Bay. We interpret the results in terms of the nature of the small-scale plasma structuring in the ionosphere and how it impacts signals of different frequencies, and attempt to infer information about the ionospheric plasma irregularity spectrum.
{"title":"Observations and Modeling of Scintillation in the Vicinity of a Polar Cap Patch","authors":"Leslie J Lamarche, Kshitija B Deshpande, Matthew D Zettergren","doi":"10.1051/swsc/2022023","DOIUrl":"https://doi.org/10.1051/swsc/2022023","url":null,"abstract":"Small-scale ionospheric plasma structures can cause scintillation in radio signals passing through the ionosphere. The relationship between the scintillated signal and how plasma structuring develops is complex. We model the development of small-scale plasma structuring in and around an idealized polar cap patch observed by the Resolute Bay Incoherent Scatter Radars (RISR) with the Geospace Environment Model for Ion-Neutral Interactions (GEMINI). Then, we simulate a signal passing through the resulting small-scale structuring with the Satellite-beacon Ionospheric-scintillation Global Model of the upper Atmosphere (SIGMA) to predict the scintillation characteristics that will be observed by a ground receiver at different stages of instability development. Finally, we compare the predicted signal characteristics with actual observations of scintillation from ground receivers in the vicinity of Resolute Bay. We interpret the results in terms of the nature of the small-scale plasma structuring in the ionosphere and how it impacts signals of different frequencies, and attempt to infer information about the ionospheric plasma irregularity spectrum.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43608809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seasonal and zonal climatologies of Rayleigh-Taylor growth rates under geomagnetically quiet conditions during solar minimum and solar moderate conditions as a function of local time and altitude are calculated using open source data and software. It is under the action of the Rayleigh-Taylor instability that plumes of depleted plasma, or plasma bubbles, are understood to develop in the bottomside of the equatorial ionosphere. The growin python module utilizes other Heliophysics python modules to collate and process vertical plasma drift to drive the SAMI2 is Another Model of the Ionosphere (SAMI2) model and subsequently calculate the flux tube integrated Rayleigh-Taylor growth rate. The process is repeated for two different types of drift inputs: the Fejer-Scherliess model and measured drifts from the Communication/Navigation Outage Forecasting System (C/NOFS). These growth rates are compared to bubble occurrence frequencies obtained from a dataset of bubbles detected by the C/NOFS satellite. There is agreement between periods of strong positive instability growth and high frequencies of bubble occurrence in both low and moderate solar activity conditions when using C/NOFS drifts. Fejer-Scherliess drifts are only in agreement with bubble occurrence frequencies during moderate solar activity conditions. Bubble occurrence frequencies are often above 25% even when growth rates in the bottomside F region are negative. The climatological nature of the growth rates discussed here begs further study into the day-to-day variability of the growth rate and its drivers.
{"title":"Growin: Modeling Ionospheric Instability Growth Rates","authors":"Jonathon Smith, J. Klenzing","doi":"10.1051/swsc/2022021","DOIUrl":"https://doi.org/10.1051/swsc/2022021","url":null,"abstract":"Seasonal and zonal climatologies of Rayleigh-Taylor growth rates under geomagnetically quiet conditions during solar minimum and solar moderate conditions as a function of local time and altitude are calculated using open source data and software. It is under the action of the Rayleigh-Taylor instability that plumes of depleted plasma, or plasma bubbles, are understood to develop in the bottomside of the equatorial ionosphere. The growin python module utilizes other Heliophysics python modules to collate and process vertical plasma drift to drive the SAMI2 is Another Model of the Ionosphere (SAMI2) model and subsequently calculate the flux tube integrated Rayleigh-Taylor growth rate. The process is repeated for two different types of drift inputs: the Fejer-Scherliess model and measured drifts from the Communication/Navigation Outage Forecasting System (C/NOFS). These growth rates are compared to bubble occurrence frequencies obtained from a dataset of bubbles detected by the C/NOFS satellite. There is agreement between periods of strong positive instability growth and high frequencies of bubble occurrence in both low and moderate solar activity conditions when using C/NOFS drifts. Fejer-Scherliess drifts are only in agreement with bubble occurrence frequencies during moderate solar activity conditions. Bubble occurrence frequencies are often above 25% even when growth rates in the bottomside F region are negative. The climatological nature of the growth rates discussed here begs further study into the day-to-day variability of the growth rate and its drivers.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41847334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yaqi Jin, L. Clausen, W. Miloch, P. Høeg, W. Jarmołowski, P. Wielgosz, J. Paziewski, B. Milanowska, M. Hoque, J. Berdermann, Haixia Lyu, M. Hernández‐Pajares, E. Monte‐Moreno, Alberto García Rigo
This paper addresses the long-term climatology (over two solar cycles) of total electron content (TEC) irregularities from a polar cap station (Thule) using rate of change of TEC index (ROTI). The climatology reveals various variabilities over different time scales, i.e., solar cycle, seasonal, and diurnal variations. These variations in different time scales can be explained by different drivers/contributors. The solar activity (represented by the solar radiation index F10.7P) dominates the longest time scale variations. The seasonal variations are controlled by the interplay of the energy input into the polar cap ionosphere and the solar illumination that damps the amplitude of ionospheric irregularities. The diurnal variations (with respect to local time) are controlled by the relative location of the station with respect to the auroral oval. We further decompose the climatology of ionospheric irregularities using the empirical orthogonal function (EOF) method. The first four EOFs could reflect the majority (99.49%) of the total data variability. By fitting the EOF coefficients using three geophysical proxies (namely, F10.7P, Bt and Dst), a climatological model of ionospheric irregularities is developed. The data-model comparison shows satisfactory results with high Pearson correlation coefficient and adequate errors. Additionally, we modeled the historical ROTI during the modern grand maximum dating back to 1965 and made the prediction during solar cycle 25. In such a way, we are able to directly compare the climatic variations of the ROTI activity across six solar cycles.
{"title":"Climatology and Modeling of Ionospheric Irregularities over Greenland Based on Empirical Orthogonal Function Method","authors":"Yaqi Jin, L. Clausen, W. Miloch, P. Høeg, W. Jarmołowski, P. Wielgosz, J. Paziewski, B. Milanowska, M. Hoque, J. Berdermann, Haixia Lyu, M. Hernández‐Pajares, E. Monte‐Moreno, Alberto García Rigo","doi":"10.1051/swsc/2022022","DOIUrl":"https://doi.org/10.1051/swsc/2022022","url":null,"abstract":"This paper addresses the long-term climatology (over two solar cycles) of total electron content (TEC) irregularities from a polar cap station (Thule) using rate of change of TEC index (ROTI). The climatology reveals various variabilities over different time scales, i.e., solar cycle, seasonal, and diurnal variations. These variations in different time scales can be explained by different drivers/contributors. The solar activity (represented by the solar radiation index F10.7P) dominates the longest time scale variations. The seasonal variations are controlled by the interplay of the energy input into the polar cap ionosphere and the solar illumination that damps the amplitude of ionospheric irregularities. The diurnal variations (with respect to local time) are controlled by the relative location of the station with respect to the auroral oval. We further decompose the climatology of ionospheric irregularities using the empirical orthogonal function (EOF) method. The first four EOFs could reflect the majority (99.49%) of the total data variability. By fitting the EOF coefficients using three geophysical proxies (namely, F10.7P, Bt and Dst), a climatological model of ionospheric irregularities is developed. The data-model comparison shows satisfactory results with high Pearson correlation coefficient and adequate errors. Additionally, we modeled the historical ROTI during the modern grand maximum dating back to 1965 and made the prediction during solar cycle 25. In such a way, we are able to directly compare the climatic variations of the ROTI activity across six solar cycles.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42469648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coronal Mass Ejections (CMEs) influence the interplanetary environment over vast distances in the solar system by injecting huge clouds of fast solar plasma and energetic particles (SEPs). A number of fundamental questions remain about how SEPs are produced, but current understanding points to CME-driven shocks and compressions in the solar corona. At the same time, unprecedented remote (AIA, LOFAR, MWA) and in situ (Parker Solar Probe, Solar Orbiter) solar observations are becoming available to constrain existing theories. Here we present a general method for recognition and tracking of objects on solar images – CME shock waves, filaments, active regions. The calculation scheme is based on a multi-scale data representation concept a-trous wavelet transform, and a set of image filtering techniques. We showcase its performance on a small set of CME-related phenomena observed with the SDO/AIA telescope. With the data represented hierarchically on different decomposition and intensity levels, our method allows to extract certain objects and their masks from the imaging observations, in order to track their evolution in time. The method presented here is general and applicable to detecting and tracking various solar and heliospheric phenomena in imaging observations. We implemented this method into a freely available Python library.
{"title":"Multi-scale Image Preprocessing and Feature Tracking for Remote CME Characterization","authors":"O. Stepanyuk, K. Kozarev, M. Nedal","doi":"10.1051/swsc/2022020","DOIUrl":"https://doi.org/10.1051/swsc/2022020","url":null,"abstract":"Coronal Mass Ejections (CMEs) influence the interplanetary environment over vast distances in the solar system by injecting huge clouds of fast solar plasma and energetic particles (SEPs). A number of fundamental questions remain about how SEPs are produced, but current understanding points to CME-driven shocks and compressions in the solar corona. At the same time, unprecedented remote (AIA, LOFAR, MWA) and in situ (Parker Solar Probe, Solar Orbiter) solar observations are becoming available to constrain existing theories. Here we present a general method for recognition and tracking of objects on solar images – CME shock waves, filaments, active regions. The calculation scheme is based on a multi-scale data representation concept a-trous wavelet transform, and a set of image filtering techniques. We showcase its performance on a small set of CME-related phenomena observed with the SDO/AIA telescope. With the data represented hierarchically on different decomposition and intensity levels, our method allows to extract certain objects and their masks from the imaging observations, in order to track their evolution in time. The method presented here is general and applicable to detecting and tracking various solar and heliospheric phenomena in imaging observations. We implemented this method into a freely available Python library.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2022-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48850630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High-energy charged plasma particles pose a danger to space technology. The accumulation of charged particles on the body of the spacecraft generates discharges. Electrostatic discharge is a source of powerful electromagnetic interference that adversely affects the functioning of individual parts and entire systems. According to statistics, in about 30% of cases, the loss of satellites are the consequences of discharges. Before the operation of spacecraft, it is necessary to calculate the spreading of currents, which requires large machine and time costs. The article proposes original approaches for quickly constructing a picture of the spreading of currents over the surface of a spacecraft due to electrification. The key point of the first approach is the construction of a limited area for calculating the flow spreading. The calculation of transient currents will only take place in the electromagnetic compatibility area specified by the user, without affecting the rest of it. The paper also developed new simplified computational schemes for a system of differential equations based on the Euler methods. With the help of new computational schemes, the time for calculating unknown quantities in a local area specified by the user has been reduced by several orders of magnitude compared to the calculation of unknown full models. The article presents conclusions on new computational schemes, indicating the complexity of their construction. The adequacy and accuracy of the new computational scheme is confirmed by a practical example.
{"title":"Development of accelerated methods for calculating the pattern of current spreading over the surface of spacecraft","authors":"A. Vostrikov, E. Prokofeva","doi":"10.1051/swsc/2022018","DOIUrl":"https://doi.org/10.1051/swsc/2022018","url":null,"abstract":"High-energy charged plasma particles pose a danger to space technology. The accumulation of charged particles on the body of the spacecraft generates discharges. Electrostatic discharge is a source of powerful electromagnetic interference that adversely affects the functioning of individual parts and entire systems. According to statistics, in about 30% of cases, the loss of satellites are the consequences of discharges. Before the operation of spacecraft, it is necessary to calculate the spreading of currents, which requires large machine and time costs. The article proposes original approaches for quickly constructing a picture of the spreading of currents over the surface of a spacecraft due to electrification. The key point of the first approach is the construction of a limited area for calculating the flow spreading. The calculation of transient currents will only take place in the electromagnetic compatibility area specified by the user, without affecting the rest of it. The paper also developed new simplified computational schemes for a system of differential equations based on the Euler methods. With the help of new computational schemes, the time for calculating unknown quantities in a local area specified by the user has been reduced by several orders of magnitude compared to the calculation of unknown full models. The article presents conclusions on new computational schemes, indicating the complexity of their construction. The adequacy and accuracy of the new computational scheme is confirmed by a practical example.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45753045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Vasylyev, Y. Béniguel, Wilken Volker, M. Kriegel, J. Berdermann
A signal, such as from a GNSS satellite or microwave sounding system, propagating in the randomly inhomogeneous ionosphere, experiences chaotic modulations of its amplitude and phase. This effect is known as scintillation. This article reviews basic theoretical concepts and simulation strategies for modeling the scintillation phenomenon. We focused our attention primarily on the methods connected with the random phase screen model. For a weak scattering regime on random ionospheric irregularities, a single phase screen model enables us to obtain the analytic expression for phase and intensity scintillation indices, as well as the statistical quantities characterizing the strength of scintillation-related fades and distortions. In the case of multiple scattering, the simulation with multiple phase screens becomes a handy tool for obtaining these indices. For both scattering regimes, the statistical properties of the ionospheric random medium play an important role in scintillation modeling and are discussed with an emphasis on related geometric aspects. As an illustration, the phase screen simulation approaches used in the global climatological scintillation model GISM is briefly discussed.
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