F. Enengl, D. Kotova, Yaqi Jin, L. Clausen, W. Miloch
Auroral particle precipitation potentially plays a main role in ionospheric plasma structuring. The impact of auroral particle precipitation on plasma structuring is investigated using multi-point measurements from scintillation receivers and all sky cameras from Longyearbyen, Ny-Ålesund and Hornsund on Svalbard. This provides us with the unique possibility of studying the spatial and temporal dynamics of the aurora. Here we consider three case studies to investigate how plasma structuring is related to different auroral forms. We demonstrate that plasma structuring impacting the GNSS signals is largest at the edges of auroral forms. Here we studied two stable arcs, two dynamic auroral bands and a spiral. Specifically for arcs we find elevated phase scintillation indices at the pole-ward edge of the aurora. This is observed for auroral oxygen emissions (557.7 nm) at 150~km in the ionospheric E-region. This altitude is also used as the ionospheric piercing point for the GNSS signals as the observations remain the same regardless of different satellite elevations and azimuths. Further, there may be a time delay between the temporal evolution of aurora (f.e. commencement and fading of auroral activity) and observations of elevated phase scintillation indices. The time delay could be explained by the intense influx of particles, which increases the plasma density and causes recombination to carry on longer, which may lead to a persistence of structures - a 'memory effect'. High values of phase scintillation indices can be observed even shortly after strong visible aurora and can then remain significant at low intensities of the aurora.
{"title":"Ionospheric Plasma Structuring in Relation to Auroral Particle Precipitation","authors":"F. Enengl, D. Kotova, Yaqi Jin, L. Clausen, W. Miloch","doi":"10.1051/swsc/2022038","DOIUrl":"https://doi.org/10.1051/swsc/2022038","url":null,"abstract":"Auroral particle precipitation potentially plays a main role in ionospheric plasma structuring. The impact of auroral particle precipitation on plasma structuring is investigated using multi-point measurements from scintillation receivers and all sky cameras from Longyearbyen, Ny-Ålesund and Hornsund on Svalbard. This provides us with the unique possibility of studying the spatial and temporal dynamics of the aurora. Here we consider three case studies to investigate how plasma structuring is related to different auroral forms. \u0000 We demonstrate that plasma structuring impacting the GNSS signals is largest at the edges of auroral forms. Here we studied two stable arcs, two dynamic auroral bands and a spiral. Specifically for arcs we find elevated phase scintillation indices at the pole-ward edge of the aurora. This is observed for auroral oxygen emissions (557.7 nm) at 150~km in the ionospheric E-region. This altitude is also used as the ionospheric piercing point for the GNSS signals as the observations remain the same regardless of different satellite elevations and azimuths. Further, there may be a time delay between the temporal evolution of aurora (f.e. commencement and fading of auroral activity) and observations of elevated phase scintillation indices. The time delay could be explained by the intense influx of particles, which increases the plasma density and causes recombination to carry on longer, which may lead to a persistence of structures - a 'memory effect'. High values of phase scintillation indices can be observed even shortly after strong visible aurora and can then remain significant at low intensities of the aurora.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48564848","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}
K. Herlingshaw, L. Baddeley, K. Oksavik, D. Lorentzen, K. Laundal
This paper details the first large scale, interhemispheric statistical study into ionospheric fast flow (>900 m/s) channels in the polar cap using the SuperDARN radar network. An automatic algorithm was applied to 6 years of data (2010 – 2016) from 8 SuperDARN radars with coverage in the polar cap regions in both hemispheres. Over 17,000 flow channels were detected, the majority of which occurred in the dayside polar cap region. To determine a statistical relationship between the flow channels and the IMF, a Monte Carlo simulation was used to generate probability distribution functions for IMF conditions and dipole tilt angles. These were used as a baseline for comparisons with IMF conditions associated with the flow channels. This analysis showed that fast flow channels are preferentially driven by IMF By dominant conditions, suggesting that a magnetic tension force on the newly reconnected field lines is required to accelerate the ionospheric plasma to the high speeds on the dayside. The flow channels also occur preferentially during disturbed IMF conditions. Large populations of flow channels were observed on the flanks of the polar cap region. This indicates that significant momentum transfer from the magnetosphere can routinely occur on open field lines on the flanks, far from the dayside and nightside reconnection regions.
{"title":"A Statistical Study of Polar Cap Flow Channels observed in Both Hemispheres using SuperDARN Radars","authors":"K. Herlingshaw, L. Baddeley, K. Oksavik, D. Lorentzen, K. Laundal","doi":"10.1051/swsc/2022037","DOIUrl":"https://doi.org/10.1051/swsc/2022037","url":null,"abstract":"This paper details the first large scale, interhemispheric statistical study into ionospheric fast flow (>900 m/s) channels in the polar cap using the SuperDARN radar network. An automatic algorithm was applied to 6 years of data (2010 – 2016) from 8 SuperDARN radars with coverage in the polar cap regions in both hemispheres. Over 17,000 flow channels were detected, the majority of which occurred in the dayside polar cap region. To determine a statistical relationship between the flow channels and the IMF, a Monte Carlo simulation was used to generate probability distribution functions for IMF conditions and dipole tilt angles. These were used as a baseline for comparisons with IMF conditions associated with the flow channels. This analysis showed that fast flow channels are preferentially driven by IMF By dominant conditions, suggesting that a magnetic tension force on the newly reconnected field lines is required to accelerate the ionospheric plasma to the high speeds on the dayside. The flow channels also occur preferentially during disturbed IMF conditions. Large populations of flow channels were observed on the flanks of the polar cap region. This indicates that significant momentum transfer from the magnetosphere can routinely occur on open field lines on the flanks, far from the dayside and nightside reconnection regions.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48416561","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}
Peng Chen, Rong Wang, Yibin Yao, Zhiyuan An, Zhihao Wang
Ionospheric diurnal double maxima (DDM) is a twin-peak pattern in the ionospheric electron density/total electron content (TEC) during the daytime. Understanding the characteristics of DDM is essential to study the physical mechanisms of the ionosphere. In this paper, the vertical TEC data (VTEC) in 2019-2020 derived from 537 globally distributed GPS stations were used to investigate the DDM phenomenon. The results reveal that the occurrence rate of DDMs is roughly quasi-symmetrical about the magnetic equator. In the northern hemisphere, it first increases, then decreases, and finally increases with the increase of magnetic latitude. The DDM phenomenon also exhibits significant seasonal variation. It mainly appears in summer/winter in the northern/southern hemisphere, and the valley and the second peak usually appear earlier in winter and later in summer. According to the difference in the magnitude of the two peaks of DDM, the DDM phenomenon is mainly manifested as the front peak significant type or the posterior peak significant type. The probability of the former shows a M-shaped variation with the increasing longitude in the middle and high latitudes of the northern hemisphere, and an inverted V-shaped variation in the high latitudes of the southern hemisphere within 180°W~60°W. The probability of the posterior peak significant type shows a trend opposite to the front peak significant type in each area. The occurrence time of DDM structures is usually about one hour later in low-latitude regions than other regions, and the duration is usually shorter than in other regions. The relative magnitude of the DDM’s twin peaks in low-latitude regions is usually smaller than that of other regions.
{"title":"On the Global Ionospheric Diurnal Double Maxima Based on GPS Vertical Total Electron Content","authors":"Peng Chen, Rong Wang, Yibin Yao, Zhiyuan An, Zhihao Wang","doi":"10.1051/swsc/2022035","DOIUrl":"https://doi.org/10.1051/swsc/2022035","url":null,"abstract":"Ionospheric diurnal double maxima (DDM) is a twin-peak pattern in the ionospheric electron density/total electron content (TEC) during the daytime. Understanding the characteristics of DDM is essential to study the physical mechanisms of the ionosphere. In this paper, the vertical TEC data (VTEC) in 2019-2020 derived from 537 globally distributed GPS stations were used to investigate the DDM phenomenon. The results reveal that the occurrence rate of DDMs is roughly quasi-symmetrical about the magnetic equator. In the northern hemisphere, it first increases, then decreases, and finally increases with the increase of magnetic latitude. The DDM phenomenon also exhibits significant seasonal variation. It mainly appears in summer/winter in the northern/southern hemisphere, and the valley and the second peak usually appear earlier in winter and later in summer. According to the difference in the magnitude of the two peaks of DDM, the DDM phenomenon is mainly manifested as the front peak significant type or the posterior peak significant type. The probability of the former shows a M-shaped variation with the increasing longitude in the middle and high latitudes of the northern hemisphere, and an inverted V-shaped variation in the high latitudes of the southern hemisphere within 180°W~60°W. The probability of the posterior peak significant type shows a trend opposite to the front peak significant type in each area. The occurrence time of DDM structures is usually about one hour later in low-latitude regions than other regions, and the duration is usually shorter than in other regions. The relative magnitude of the DDM’s twin peaks in low-latitude regions is usually smaller than that of other regions.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48105122","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}
Yuhao Zheng, Chao Xiong, Yaqi Jin, Dun Liu, K. Oksavik, Chunyu Xu, Yixun Zhu, Shunzu Gao, Fengjue Wang, Hui Wang, F. Yin
Different indices have been used to reflect, or monitor the ionospheric scintillation, e.g. the detrended carrier phase, δφ, S4, the rate of change of the total electron content index (ROTI), as well as the ionosphere‐free linear combination (IFLC) of two carrier phases. However, few studies have been performed to investigate the refractive and diffractive contributions to these indices, especially during geomagnetic storms. In this study, we analyze the high-resolution (50 Hz) phase and amplitude measurements from four high-latitude stations in Svalbard, Norway during the geomagnetic storm on 7-8 September 2017. Our results show that at high latitudes, the high-pass filter with a standard cutoff frequency of 0.1 Hz sometimes cannot effectively remove the refraction driven phase variations, especially during the geomagnetic storm, leading to a remaining refraction contribution to the detrended carrier phase and δφ when scintillation happens. In the meanwhile, as ROTI is sensitive to the TEC gradients, regardless of small- or large-scale ionospheric structures, both refraction and diffraction effects can cause visible fluctuations of ROTI. For most of the scintillation events, the phase indices (including detrended carrier phase, δφ, and ROTI), IFLC and S4 show consistent fluctuations, indicating that diffraction usually occurs simultaneously with refraction during scintillation. One interesting feature is that although the IFLC and S4 are thought to be both related to the diffraction effect, they do not always show simultaneous correspondence during scintillations. The IFLC is enhanced during the geomagnetic storm, while such a feature is not seen in S4. We suggest that the enhanced IFLC during geomagnetic storm is caused by the increased high-frequency phase power, which should be related to the enhanced density of small-scale irregularities during storm periods.
{"title":"The refractive and diffractive contributions to GPS signal scintillation at high latitude during the geomagnetic storm on 7-8 September 2017","authors":"Yuhao Zheng, Chao Xiong, Yaqi Jin, Dun Liu, K. Oksavik, Chunyu Xu, Yixun Zhu, Shunzu Gao, Fengjue Wang, Hui Wang, F. Yin","doi":"10.1051/swsc/2022036","DOIUrl":"https://doi.org/10.1051/swsc/2022036","url":null,"abstract":"Different indices have been used to reflect, or monitor the ionospheric scintillation, e.g. the detrended carrier phase, δφ, S4, the rate of change of the total electron content index (ROTI), as well as the ionosphere‐free linear combination (IFLC) of two carrier phases. However, few studies have been performed to investigate the refractive and diffractive contributions to these indices, especially during geomagnetic storms. In this study, we analyze the high-resolution (50 Hz) phase and amplitude measurements from four high-latitude stations in Svalbard, Norway during the geomagnetic storm on 7-8 September 2017. Our results show that at high latitudes, the high-pass filter with a standard cutoff frequency of 0.1 Hz sometimes cannot effectively remove the refraction driven phase variations, especially during the geomagnetic storm, leading to a remaining refraction contribution to the detrended carrier phase and δφ when scintillation happens. In the meanwhile, as ROTI is sensitive to the TEC gradients, regardless of small- or large-scale ionospheric structures, both refraction and diffraction effects can cause visible fluctuations of ROTI. For most of the scintillation events, the phase indices (including detrended carrier phase, δφ, and ROTI), IFLC and S4 show consistent fluctuations, indicating that diffraction usually occurs simultaneously with refraction during scintillation. One interesting feature is that although the IFLC and S4 are thought to be both related to the diffraction effect, they do not always show simultaneous correspondence during scintillations. The IFLC is enhanced during the geomagnetic storm, while such a feature is not seen in S4. We suggest that the enhanced IFLC during geomagnetic storm is caused by the increased high-frequency phase power, which should be related to the enhanced density of small-scale irregularities during storm periods.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42709745","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}
R. Kataoka, Tatsuhiko Sato, C. Kato, A. Kadokura, M. Kozai, S. Miyake, K. Murase, Lihito Yoshida, Y. Tomikawa, K. Munakata
Solar modulation of galactic cosmic rays around the solar minimum in 2019-2020 looks different in the secondary neutrons and muons observed at the ground. To compare the solar modulation of primary cosmic rays in detail, we must remove the possible seasonal variations caused by the atmosphere and surrounding environment. As such surrounding environment effects, we evaluate the snow cover effect on neutron count rate and the atmospheric temperature effect on muon count rate, both simultaneously observed at Syowa Station in the Antarctic (69.01º S, 39.59º E). A machine learning technique, Echo State Network (ESN), is applied to estimate both effects hidden in the observed time series of the count rate. We show that the ESN with the input of GDAS data (temperature time series at 925, 850, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, and 20 hPa) at the local position can be useful for both the temperature correction for muons and snow cover correction for neutrons. The corrected muon count rate starts decreasing in late 2019, preceding the corrected neutron count rate which starts decreasing in early 2020, possibly indicating the rigidity-dependent solar modulation in the heliosphere.
{"title":"Local environmental effects on cosmic ray observations at Syowa Station in the Antarctic: PARMA-based snow cover correction for neutrons and machine learning approach for neutrons and muons","authors":"R. Kataoka, Tatsuhiko Sato, C. Kato, A. Kadokura, M. Kozai, S. Miyake, K. Murase, Lihito Yoshida, Y. Tomikawa, K. Munakata","doi":"10.1051/swsc/2022033","DOIUrl":"https://doi.org/10.1051/swsc/2022033","url":null,"abstract":"Solar modulation of galactic cosmic rays around the solar minimum in 2019-2020 looks different in the secondary neutrons and muons observed at the ground. To compare the solar modulation of primary cosmic rays in detail, we must remove the possible seasonal variations caused by the atmosphere and surrounding environment. As such surrounding environment effects, we evaluate the snow cover effect on neutron count rate and the atmospheric temperature effect on muon count rate, both simultaneously observed at Syowa Station in the Antarctic (69.01º S, 39.59º E). A machine learning technique, Echo State Network (ESN), is applied to estimate both effects hidden in the observed time series of the count rate. We show that the ESN with the input of GDAS data (temperature time series at 925, 850, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, and 20 hPa) at the local position can be useful for both the temperature correction for muons and snow cover correction for neutrons. The corrected muon count rate starts decreasing in late 2019, preceding the corrected neutron count rate which starts decreasing in early 2020, possibly indicating the rigidity-dependent solar modulation in the heliosphere.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46218119","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}
R. Kataoka, D. Shiota, H. Fujiwara, H. Jin, C. Tao, H. Shinagawa, Y. Miyoshi
The accidental reentry of 38 Starlink satellites occurred in early February 2022, associated with the occurrence of moderate magnetic storms. A poorly understood structure of coronal mass ejections (CMEs) caused the magnetic storms at unexpected timing. Therefore, a better understanding of minor CME structures is necessary for the modern space weather forecast. During this event, the "up to 50%" enhancement of air drag force was observed at ~200 km altitude, preventing the satellites’ safety operations. Although the mass density enhancement predicted by the NRLMSIS2.0 empirical model is less than 25 % under the present moderate magnetic storms, the real-time GAIA simulation showed a mass density enhancement of up to 50%. Further, the real-time GAIA simulation suggests that the actual thermospheric disturbances at 200 km altitude may occur with larger amplitude in a broader area than previously thought.
{"title":"Unexpected space weather causing the reentry of 38 Starlink satellites in February 2022","authors":"R. Kataoka, D. Shiota, H. Fujiwara, H. Jin, C. Tao, H. Shinagawa, Y. Miyoshi","doi":"10.1051/swsc/2022034","DOIUrl":"https://doi.org/10.1051/swsc/2022034","url":null,"abstract":"The accidental reentry of 38 Starlink satellites occurred in early February 2022, associated with the occurrence of moderate magnetic storms. A poorly understood structure of coronal mass ejections (CMEs) caused the magnetic storms at unexpected timing. Therefore, a better understanding of minor CME structures is necessary for the modern space weather forecast. During this event, the \"up to 50%\" enhancement of air drag force was observed at ~200 km altitude, preventing the satellites’ safety operations. Although the mass density enhancement predicted by the NRLMSIS2.0 empirical model is less than 25 % under the present moderate magnetic storms, the real-time GAIA simulation showed a mass density enhancement of up to 50%. Further, the real-time GAIA simulation suggests that the actual thermospheric disturbances at 200 km altitude may occur with larger amplitude in a broader area than previously thought.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45679330","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}
T. Verhulst, D. Altadill, V. Barta, A. Belehaki, D. Burešová, C. Cesaroni, I. Galkin, Marco Guerra, A. Ippolito, T. Herekakis, D. Kouba, J. Mielich, A. Segarra, L. Spogli, I. Tsagouri
The 15 January 2022 eruption of the Hunga volcano provides a unique opportunity to study the reaction of the ionosphere to large explosive events. In particular, this event allows us to study the global propagation of travelling ionospheric disturbances using various instruments. We focus on the detection of the ionospheric disturbances caused by this eruption over Europe, where dense networks of both ionosondes and GNSS receivers are available. This event took place on the day of a geomagnetic storm. We show how data from different instruments and from different observatories can be combined to clearly distinguish the TIDs produced by the eruption from those caused by concurrent geomagnetic activity. The Lamb wave front was detected as the strongest disturbance in the ionosphere, travelling at between 300 and 340 m/s, consistent with the disturbances in the lower atmosphere. By comparing observations obtained from multiple types of instruments, we also show that TIDs produced by various mechanisms are present simultaneously, with different types of waves affecting different physical quantities. This illustrates the importance of analysing data from multiple independent instruments in order to obtain a full picture of an event like this one, as relying on only a single data source might result in some effects going unobserved.
{"title":"Multi-instrument detection in Europe of ionospheric disturbances caused\u0000by the 15 January 2022 eruption of the Hunga volcano","authors":"T. Verhulst, D. Altadill, V. Barta, A. Belehaki, D. Burešová, C. Cesaroni, I. Galkin, Marco Guerra, A. Ippolito, T. Herekakis, D. Kouba, J. Mielich, A. Segarra, L. Spogli, I. Tsagouri","doi":"10.1051/swsc/2022032","DOIUrl":"https://doi.org/10.1051/swsc/2022032","url":null,"abstract":"The 15 January 2022 eruption of the Hunga volcano provides a unique opportunity to study the reaction of the ionosphere to large explosive events. In particular, this event allows us to study the global propagation of travelling ionospheric disturbances using various instruments. We focus on the detection of the ionospheric disturbances caused by this eruption over Europe, where dense networks of both ionosondes and GNSS receivers are available.\u0000This event took place on the day of a geomagnetic storm. We show how data from different instruments and from different observatories can be combined to clearly distinguish the TIDs produced by the eruption from those caused by concurrent geomagnetic activity. The Lamb wave front was detected as the strongest disturbance in the ionosphere, travelling at between 300 and 340 m/s, consistent with the disturbances in the lower atmosphere.\u0000By comparing observations obtained from multiple types of instruments, we also show that TIDs produced by various mechanisms are present simultaneously, with different types of waves affecting different physical quantities. This illustrates the importance of analysing data from multiple independent instruments in order to obtain a full picture of an event like this one, as relying on only a single data source might result in some effects going unobserved.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2022-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48860801","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}
A. Cesarini, C. Grimani, M. Fabi, Federico Sabbatini, M. Villani, S. Benella, D. Telloni
The Laser Interferometer Space Antenna (LISA) of the European Space Agency (ESA) will be the first low-frequency gravitational-wave observatory orbiting the Sun at 1 AU. The LISA Pathfinder (LPF) mission, aiming at testing of the instruments to be located on board the LISA spacecraft (S/C), hosted, among the others, fluxgate magnetometers and a particle detector as parts of a diagnostics subsystem. These instruments allowed us for the estimate of the magnetic and Coulomb spurious forces acting on the test masses that constitute the mirrors of the interferometer. With these instruments we also had the possibility to study the galactic cosmic-ray short term-term variations as a function of the particle energy and the associated interplanetary disturbances. Platform magnetometers and particle detectors will be also placed on board each LISA S/C. This work reports about an empirical method that allowed us to disentangle the interplanetary and onboard-generated components of the magnetic field by using the LPF magnetometer measurements. Moreover, we estimate the number and fluence of solar energetic particle events expected to be observed with the ESA Next Generation Radiation Monitor during the mission lifetime. An additional cosmic-ray detector, similar to that designed for LPF, in combination with magnetometers, would permit to observe the evolution of recurrent and non-recurrent galactic cosmic-ray variations and associated increases of the interplanetary magnetic field at the transit of high-speed solar wind streams and interplanetary counterparts of coronal mass ejections.
{"title":"Interplanetary medium monitoring with LISA: lessons from LISA Pathfinder","authors":"A. Cesarini, C. Grimani, M. Fabi, Federico Sabbatini, M. Villani, S. Benella, D. Telloni","doi":"10.1051/swsc/2022031","DOIUrl":"https://doi.org/10.1051/swsc/2022031","url":null,"abstract":"The Laser Interferometer Space Antenna (LISA) of the European Space Agency (ESA) will be the first low-frequency gravitational-wave observatory orbiting the Sun at 1 AU. \u0000\u0000The LISA Pathfinder (LPF) mission, aiming at testing of the instruments to be located on board the LISA spacecraft (S/C), hosted, among the others, fluxgate magnetometers and a particle detector as parts of a diagnostics subsystem. \u0000\u0000These instruments allowed us for the estimate of the magnetic and Coulomb spurious forces acting on the test masses that constitute the mirrors of the interferometer. \u0000\u0000With these instruments we also had the possibility to study the galactic cosmic-ray short term-term variations as a function of the particle energy and the associated interplanetary disturbances.\u0000\u0000Platform magnetometers and particle detectors will be also placed on board each LISA S/C.\u0000\u0000This work reports about an empirical method that allowed us to disentangle the interplanetary and onboard-generated components of the magnetic field by using the LPF magnetometer measurements.\u0000\u0000Moreover, we estimate the number and fluence of solar energetic particle events expected to be observed with the ESA Next Generation Radiation Monitor during the mission lifetime. An additional cosmic-ray detector, similar to that designed for LPF, in combination with magnetometers, would permit to observe the evolution of recurrent and non-recurrent galactic cosmic-ray variations and associated increases of the interplanetary magnetic field at the transit of high-speed solar wind streams and interplanetary counterparts of coronal mass ejections.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2022-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46708676","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}
Ben Boyde, A. Wood, G. Dorrian, Richard A Fallows, D. Themens, J. Mielich, S. Elvidge, M. Mevius, P. Zucca, B. Dabrowski, A. Krankowski, C. Vocks, M. Bisi
Observations made using the LOw Frequency ARray (LOFAR) between 10:15 and 11:48 UT on the 15th of September 2018 over a bandwidth of approximately 25-65 MHz contain discrete pseudo-periodic features of ionospheric origin. These features occur with a period of approximately ten minutes and collectively last roughly an hour. They are strongly frequency dependent, broadening significantly in time towards the lower frequencies, and show an overlaid pattern of diffraction fringes. By modelling the ionosphere as a thin phase screen containing a wave-like disturbance, we are able to replicate the observations, suggesting that they are associated with small-scale travelling ionospheric disturbances (TIDs). This modelling indicates that the features observed here require a compact radio source at a low elevation, and that the TID or TIDs in question have a wavelength ~30 km. Several features suggest the presence of deviations from an idealised sinusoidal wave form. These results demonstrate LOFAR's capability to identify and characterise small-scale ionospheric structures.
{"title":"lensing from small-scale travelling ionospheric disturbances observed using lofar","authors":"Ben Boyde, A. Wood, G. Dorrian, Richard A Fallows, D. Themens, J. Mielich, S. Elvidge, M. Mevius, P. Zucca, B. Dabrowski, A. Krankowski, C. Vocks, M. Bisi","doi":"10.1051/swsc/2022030","DOIUrl":"https://doi.org/10.1051/swsc/2022030","url":null,"abstract":"Observations made using the LOw Frequency ARray (LOFAR) between 10:15 and 11:48 UT on the 15th of September 2018 over a bandwidth of approximately 25-65 MHz contain discrete pseudo-periodic features of ionospheric origin. These features occur with a period of approximately ten minutes and collectively last roughly an hour. They are strongly frequency dependent, broadening significantly in time towards the lower frequencies, and show an overlaid pattern of diffraction fringes. By modelling the ionosphere as a thin phase screen containing a wave-like disturbance, we are able to replicate the observations, suggesting that they are associated with small-scale travelling ionospheric disturbances (TIDs). This modelling indicates that the features observed here require a compact radio source at a low elevation, and that the TID or TIDs in question have a wavelength ~30 km. Several features suggest the presence of deviations from an idealised sinusoidal wave form. These results demonstrate LOFAR's capability to identify and characterise small-scale ionospheric structures.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47744630","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}
J. Paziewski, P. Høeg, R. Sieradzki, Yaqi Jin, W. Jarmołowski, M. Mainul Hoque, J. Berdermann, M. Hernández‐Pajares, P. Wielgosz, Haixia Lyu, W. Miloch, R. Orús-Pérez
Ionospheric irregularities impair Global Navigation Satellite System (GNSS) signals and, in turn, affect the performance of GNSS positioning. Such effects are especially evident at low and high latitudes, which are currently gaining the attention of research and industry sectors. This study evaluates the impact of ionospheric irregularities on GNSS positioning in Greenland. We assess the performance of positioning methods that meet the demands of a wide range of users. In particular, we address the needs of the users of mass-market single-frequency receivers and those who require a solution of high precision provided by geodetic dual-frequency receivers. We take advantage of the datasets collected during three ionospheric storms: the St. Patrick’s Day storm of March 17, 2015, the storm on June 22, 2015, and another on August 25–26, 2018. We discover a significant impact of the ionospheric disturbances on the ambiguity resolution performance and the accuracy of the float solution in Real Time Kinematics (RTK) positioning. Next, assessing the single-frequency ionosphere-free Precise Point Positioning (PPP), we demonstrate that the model is generally unaffected by ionospheric disturbances. Hence, the model is predestined for the application by the users of single-frequency receivers in the areas of frequent ionospheric disturbances. Finally, based on the observation analyses, we reveal that phase signals on the L2 frequency band are more prone to the cycle slips induced by ionospheric irregularities than those transmitted on the L1. Such signal properties explain a noticeable decline in the dual-frequency RTK performance during the ionospherically disturbed period and merely no effect for the single-frequency ionosphere-free PPP model.
{"title":"The implications of ionospheric disturbances for precise GNSS positioning in Greenland","authors":"J. Paziewski, P. Høeg, R. Sieradzki, Yaqi Jin, W. Jarmołowski, M. Mainul Hoque, J. Berdermann, M. Hernández‐Pajares, P. Wielgosz, Haixia Lyu, W. Miloch, R. Orús-Pérez","doi":"10.1051/swsc/2022029","DOIUrl":"https://doi.org/10.1051/swsc/2022029","url":null,"abstract":"Ionospheric irregularities impair Global Navigation Satellite System (GNSS) signals and, in turn, affect the performance of GNSS positioning. Such effects are especially evident at low and high latitudes, which are currently gaining the attention of research and industry sectors. This study evaluates the impact of ionospheric irregularities on GNSS positioning in Greenland. We assess the performance of positioning methods that meet the demands of a wide range of users. In particular, we address the needs of the users of mass-market single-frequency receivers and those who require a solution of high precision provided by geodetic dual-frequency receivers. We take advantage of the datasets collected during three ionospheric storms: the St. Patrick’s Day storm of March 17, 2015, the storm on June 22, 2015, and another on August 25–26, 2018. We discover a significant impact of the ionospheric disturbances on the ambiguity resolution performance and the accuracy of the float solution in Real Time Kinematics (RTK) positioning. Next, assessing the single-frequency ionosphere-free Precise Point Positioning (PPP), we demonstrate that the model is generally unaffected by ionospheric disturbances. Hence, the model is predestined for the application by the users of single-frequency receivers in the areas of frequent ionospheric disturbances. Finally, based on the observation analyses, we reveal that phase signals on the L2 frequency band are more prone to the cycle slips induced by ionospheric irregularities than those transmitted on the L1. Such signal properties explain a noticeable decline in the dual-frequency RTK performance during the ionospherically disturbed period and merely no effect for the single-frequency ionosphere-free PPP model.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2022-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46203206","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}
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