{"title":"Hydrogen atoms near the exobase are cold: independent observations do not support the hot exosphere concept","authors":"Dmytro Kotov, Oleksandr Bogomaz","doi":"10.3389/fspas.2023.1200959","DOIUrl":"https://doi.org/10.3389/fspas.2023.1200959","url":null,"abstract":"OPINION article Front. Astron. Space Sci., 10 October 2023Sec. Space Physics Volume 10 - 2023 | https://doi.org/10.3389/fspas.2023.1200959","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136357222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
The accurate modelling of the point spread function (PSF) is of paramount importance in astronomical observations, as it allows for the correction of distortions and blurring caused by the telescope and atmosphere. PSF modelling is crucial for accurately measuring celestial objects’ properties. The last decades have brought us a steady increase in the power and complexity of astronomical telescopes and instruments. Upcoming galaxy surveys like Euclid and Legacy Survey of Space and Time (LSST) will observe an unprecedented amount and quality of data. Modelling the PSF for these new facilities and surveys requires novel modelling techniques that can cope with the ever-tightening error requirements. The purpose of this review is threefold. Firstly, we introduce the optical background required for a more physically motivated PSF modelling and propose an observational model that can be reused for future developments. Secondly, we provide an overview of the different physical contributors of the PSF, which includes the optic- and detector-level contributors and atmosphere. We expect that the overview will help better understand the modelled effects. Thirdly, we discuss the different methods for PSF modelling from the parametric and non-parametric families for ground- and space-based telescopes, with their advantages and limitations. Validation methods for PSF models are then addressed, with several metrics related to weak-lensing studies discussed in detail. Finally, we explore current challenges and future directions in PSF modelling for astronomical telescopes.
{"title":"Point spread function modelling for astronomical telescopes: a review focused on weak gravitational lensing studies","authors":"Liaudat, Tobias, Starck, Jean-Luc, Kilbinger, Martin, Frugier, Pierre-Antoine","doi":"10.3389/fspas.2023.1158213","DOIUrl":"https://doi.org/10.3389/fspas.2023.1158213","url":null,"abstract":"The accurate modelling of the point spread function (PSF) is of paramount importance in astronomical observations, as it allows for the correction of distortions and blurring caused by the telescope and atmosphere. PSF modelling is crucial for accurately measuring celestial objects’ properties. The last decades have brought us a steady increase in the power and complexity of astronomical telescopes and instruments. Upcoming galaxy surveys like Euclid and Legacy Survey of Space and Time (LSST) will observe an unprecedented amount and quality of data. Modelling the PSF for these new facilities and surveys requires novel modelling techniques that can cope with the ever-tightening error requirements. The purpose of this review is threefold. Firstly, we introduce the optical background required for a more physically motivated PSF modelling and propose an observational model that can be reused for future developments. Secondly, we provide an overview of the different physical contributors of the PSF, which includes the optic- and detector-level contributors and atmosphere. We expect that the overview will help better understand the modelled effects. Thirdly, we discuss the different methods for PSF modelling from the parametric and non-parametric families for ground- and space-based telescopes, with their advantages and limitations. Validation methods for PSF models are then addressed, with several metrics related to weak-lensing studies discussed in detail. Finally, we explore current challenges and future directions in PSF modelling for astronomical telescopes.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135043745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Maps of lunar wrinkle ridges (LWRs) were created from 70°N to 70°S and 140°E to 140°W (extracted and highlighted the major LWRs area) using automated LWRs detection process with Lunar Reconnaissance Orbiter Camera wide range angle camera and Lunar Orbiter Laser Altimeter data. Automatic detection of LWRs is challenging because the ridges are of irregular shapes and many ridges have been eroded and/or degraded over time. It’s a preliminary study of automated ridge detection from DEM data. Statistics and measurements of the extracted LWRs, including orientation, extent, length, height, and elevation offset, were performed based on the mapping of lunar ridges. The identified ridges were classified based on their orientation, distribution, direction, and each class were further divided over basalts, and nearby highlands. According to the findings, 3,375 segments with a total length of 26,455.01 km were identified, and the average elevation offset, width, and height of all the wrinkle ridges were 40.39 m, 3.47 km, and 0.29 km respectively after weighting by length. The LWRs were divided into three morphologies and distributions: parallel ridges, isolated ridges, and concentric ridges. The vast majority of LWRs were found in basalts area, with an extension into neighboring highland. The relations between the morphological parameters were further quantitatively analyzed, and a similar linear correlation between the width and height was found in each class of lunar ridges, implying that small and large ridges were formed as a continuum and that the three classes of ridges were probably formed by some common processes. Finally, the relations between the lunar wrinkle ridges and other geomorphic phenomena were analyzed, indicating that purely volcanic origin or buried premare structures are difficult to reconcile with the investigation. In addition, the consistency between the occurrence of the lunar wrinkle ridges and the thickness of lunar maria indicates that the formation of lunar wrinkle ridges is closely related to the lunar maria; nevertheless, the statistical NW direction of individual classes of LWRs also proposes the presence of an appropriate stress field during the process of their formation.
{"title":"Analysis and mapping of lunar wrinkle ridges (LWRs) using automated LWRs detection process with LROC-WAC and LOLA data","authors":"Aqil Tariq, Jianguo Yan, Qingyun Deng, Jean-Pierre Barriot","doi":"10.3389/fspas.2023.1037395","DOIUrl":"https://doi.org/10.3389/fspas.2023.1037395","url":null,"abstract":"Maps of lunar wrinkle ridges (LWRs) were created from 70°N to 70°S and 140°E to 140°W (extracted and highlighted the major LWRs area) using automated LWRs detection process with Lunar Reconnaissance Orbiter Camera wide range angle camera and Lunar Orbiter Laser Altimeter data. Automatic detection of LWRs is challenging because the ridges are of irregular shapes and many ridges have been eroded and/or degraded over time. It’s a preliminary study of automated ridge detection from DEM data. Statistics and measurements of the extracted LWRs, including orientation, extent, length, height, and elevation offset, were performed based on the mapping of lunar ridges. The identified ridges were classified based on their orientation, distribution, direction, and each class were further divided over basalts, and nearby highlands. According to the findings, 3,375 segments with a total length of 26,455.01 km were identified, and the average elevation offset, width, and height of all the wrinkle ridges were 40.39 m, 3.47 km, and 0.29 km respectively after weighting by length. The LWRs were divided into three morphologies and distributions: parallel ridges, isolated ridges, and concentric ridges. The vast majority of LWRs were found in basalts area, with an extension into neighboring highland. The relations between the morphological parameters were further quantitatively analyzed, and a similar linear correlation between the width and height was found in each class of lunar ridges, implying that small and large ridges were formed as a continuum and that the three classes of ridges were probably formed by some common processes. Finally, the relations between the lunar wrinkle ridges and other geomorphic phenomena were analyzed, indicating that purely volcanic origin or buried premare structures are difficult to reconcile with the investigation. In addition, the consistency between the occurrence of the lunar wrinkle ridges and the thickness of lunar maria indicates that the formation of lunar wrinkle ridges is closely related to the lunar maria; nevertheless, the statistical NW direction of individual classes of LWRs also proposes the presence of an appropriate stress field during the process of their formation.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135350972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
The ion upflow associated with the subauroral ion drift (SAID) is a crucial component in the exchange of particles between the ionosphere and the ring currents. The ion upflow associated with the double-peak subauroral ion drift (DSAID), which is a subclass of the SAID, is more complex compared to SAID. In this study, we conducted a statistical analysis of the ion upflow associated with DSAID using Defense Meteorological Satellite Program (DMSP) F16–F18 data spanning 11 years (2010–2020) in the Northern Hemisphere. Our findings revealed that ion upflow associated with DSAID can exhibit either a double-peak or a one-peak upflow. The statistical characteristics of these two types of events displayed significant differences. In DSAID with a double-peak upflow event, the velocity of DSAID around the high-latitude peak was greater than that around the low-latitude peak. However, in DSAID with a one-peak upflow event, the DSAID velocities around the two peaks were very similar. Based on the formation mechanism of DSAID and the process of frictional heating in the ionosphere, we proposed that the formation of DSAID with a double-peak upflow and DSAID with a one-peak upflow are likely related to the formation process of DSAID.
{"title":"A statistical analysis and comparison of the fine structures of the ion upflow associated with the double-peak subauroral ion drift","authors":"Qiang Zhang, De-Sheng Han, Shang-Chun Teng, Zhi-Wei Wang, Q.-H. Zhang, Zan-Yang Xing, Yong Wang, Yu-Zhang Ma","doi":"10.3389/fspas.2023.1254243","DOIUrl":"https://doi.org/10.3389/fspas.2023.1254243","url":null,"abstract":"The ion upflow associated with the subauroral ion drift (SAID) is a crucial component in the exchange of particles between the ionosphere and the ring currents. The ion upflow associated with the double-peak subauroral ion drift (DSAID), which is a subclass of the SAID, is more complex compared to SAID. In this study, we conducted a statistical analysis of the ion upflow associated with DSAID using Defense Meteorological Satellite Program (DMSP) F16–F18 data spanning 11 years (2010–2020) in the Northern Hemisphere. Our findings revealed that ion upflow associated with DSAID can exhibit either a double-peak or a one-peak upflow. The statistical characteristics of these two types of events displayed significant differences. In DSAID with a double-peak upflow event, the velocity of DSAID around the high-latitude peak was greater than that around the low-latitude peak. However, in DSAID with a one-peak upflow event, the DSAID velocities around the two peaks were very similar. Based on the formation mechanism of DSAID and the process of frictional heating in the ionosphere, we proposed that the formation of DSAID with a double-peak upflow and DSAID with a one-peak upflow are likely related to the formation process of DSAID.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135590697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2023-10-04DOI: 10.3389/fspas.2023.1224659
Raluca Ilie, Mei-Yun Lin, Muhammad Fraz Bashir, Abhiraj Majumder
Most studies have yet to consider and assess the transport and energization of N + ions throughout the ionosphere-magnetosphere system, in addition to that of O + and other heavy ion species. The limited observational record of N + presence in near-Earth plasma, partly due to instrument limitations to distinguish ion species of similar masses, has obscured its significant contribution to the near-Earth plasma. This letter reviews the most notable observations of N + ions, starting from the early low altitude measurements from Sputnik III in the ionosphere to the measurements reported by the Enhanced Polar Outflow Probe (e-POP) mission. The available observational data set suggests that nitrogen ions are constant companions of outflowing oxygen ions, and their abundances vary with season, solar cycle, time of day, and geomagnetic activity. This strong record of nitrogen presence in the ionosphere-magnetosphere system raises the question of ionic composition and the need for caution when interpreting O + measurements from current missions.
{"title":"A review of N+ observations in the ionosphere-magnetosphere system","authors":"Raluca Ilie, Mei-Yun Lin, Muhammad Fraz Bashir, Abhiraj Majumder","doi":"10.3389/fspas.2023.1224659","DOIUrl":"https://doi.org/10.3389/fspas.2023.1224659","url":null,"abstract":"Most studies have yet to consider and assess the transport and energization of N + ions throughout the ionosphere-magnetosphere system, in addition to that of O + and other heavy ion species. The limited observational record of N + presence in near-Earth plasma, partly due to instrument limitations to distinguish ion species of similar masses, has obscured its significant contribution to the near-Earth plasma. This letter reviews the most notable observations of N + ions, starting from the early low altitude measurements from Sputnik III in the ionosphere to the measurements reported by the Enhanced Polar Outflow Probe (e-POP) mission. The available observational data set suggests that nitrogen ions are constant companions of outflowing oxygen ions, and their abundances vary with season, solar cycle, time of day, and geomagnetic activity. This strong record of nitrogen presence in the ionosphere-magnetosphere system raises the question of ionic composition and the need for caution when interpreting O + measurements from current missions.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135592209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2023-10-03DOI: 10.3389/fspas.2023.1246978
Qian Jiao, Yu Gao, Qinghua Tan, Yang Gao
We present a statistical study on dense molecular gas tracers of HCN (4–3), HCO + (4–3) lines and molecular tracers of [C i ], and CO observations for a sample of 26 infrared bright star-forming (SF) galaxies. We investigate the dependence of dense gas star formation efficiency traced by HCN (4–3), HCO + (4–3) (that is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m2"><mml:msub><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mtext>IR</mml:mtext></mml:mrow></mml:msub><mml:mo>/</mml:mo><mml:msubsup><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mtext>HCN </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mn>4</mml:mn><mml:mo>-</mml:mo><mml:mn>3</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msubsup></mml:math> , and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m3"><mml:msub><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mtext>IR</mml:mtext></mml:mrow></mml:msub><mml:mo>/</mml:mo><mml:msubsup><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">H</mml:mi><mml:mi mathvariant="normal">C</mml:mi><mml:msup><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:mspace width="0.3333em" /><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mrow><mml:mn mathvariant="normal">4</mml:mn><mml:mo>−</mml:mo><mml:mn mathvariant="normal">3</mml:mn></mml:mrow><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msubsup></mml:math> ), and luminosity ratio of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m4"><mml:msubsup><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mtext>HCN </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mn>4</mml:mn><mml:mo>-</mml:mo><mml:mn>3</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msubsup><mml:mo>/</mml:mo><mml:msubsup><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">H</mml:mi><mml:mi mathvariant="normal">C</mml:mi><mml:msup><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:mspace width="0.3333em" /><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mrow><mml:mn mathvariant="normal">4</mml:mn><mml:mo>−</mml:mo><mml:mn mathvariant="normal">3</mml:mn></mml:mrow><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msubsup></mml:math> on [C i ]-CO ratios of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m5"><mml:msubsup><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mrow><mml:mo>[</mml:mo><mml:mtext>C I</mml:mtext><mml:mo>]</mml:mo></mml:mrow><mml:mtext> </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mn>1</mml:mn><mml:mo>-</mml:mo><mml:mtext>0</mml:mtext><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msubsup><mml:mo>/</mml:mo><mml:msubsup><mml:mrow><mml:mi>L</mml:m
{"title":"Dense gas star formation efficiency and the LHCN (4−3)′/LHCO+(4−3)′ ratio: insights from a statistical study of infrared bright star-forming galaxies","authors":"Qian Jiao, Yu Gao, Qinghua Tan, Yang Gao","doi":"10.3389/fspas.2023.1246978","DOIUrl":"https://doi.org/10.3389/fspas.2023.1246978","url":null,"abstract":"We present a statistical study on dense molecular gas tracers of HCN (4–3), HCO + (4–3) lines and molecular tracers of [C i ], and CO observations for a sample of 26 infrared bright star-forming (SF) galaxies. We investigate the dependence of dense gas star formation efficiency traced by HCN (4–3), HCO + (4–3) (that is <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m2\"><mml:msub><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mtext>IR</mml:mtext></mml:mrow></mml:msub><mml:mo>/</mml:mo><mml:msubsup><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mtext>HCN </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mn>4</mml:mn><mml:mo>-</mml:mo><mml:mn>3</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msubsup></mml:math> , and <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m3\"><mml:msub><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mtext>IR</mml:mtext></mml:mrow></mml:msub><mml:mo>/</mml:mo><mml:msubsup><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant=\"normal\">H</mml:mi><mml:mi mathvariant=\"normal\">C</mml:mi><mml:msup><mml:mrow><mml:mi mathvariant=\"normal\">O</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:mspace width=\"0.3333em\" /><mml:mrow><mml:mo stretchy=\"false\">(</mml:mo><mml:mrow><mml:mn mathvariant=\"normal\">4</mml:mn><mml:mo>−</mml:mo><mml:mn mathvariant=\"normal\">3</mml:mn></mml:mrow><mml:mo stretchy=\"false\">)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msubsup></mml:math> ), and luminosity ratio of <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m4\"><mml:msubsup><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mtext>HCN </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mn>4</mml:mn><mml:mo>-</mml:mo><mml:mn>3</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msubsup><mml:mo>/</mml:mo><mml:msubsup><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant=\"normal\">H</mml:mi><mml:mi mathvariant=\"normal\">C</mml:mi><mml:msup><mml:mrow><mml:mi mathvariant=\"normal\">O</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:mspace width=\"0.3333em\" /><mml:mrow><mml:mo stretchy=\"false\">(</mml:mo><mml:mrow><mml:mn mathvariant=\"normal\">4</mml:mn><mml:mo>−</mml:mo><mml:mn mathvariant=\"normal\">3</mml:mn></mml:mrow><mml:mo stretchy=\"false\">)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msubsup></mml:math> on [C i ]-CO ratios of <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m5\"><mml:msubsup><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mrow><mml:mo>[</mml:mo><mml:mtext>C I</mml:mtext><mml:mo>]</mml:mo></mml:mrow><mml:mtext> </mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mn>1</mml:mn><mml:mo>-</mml:mo><mml:mtext>0</mml:mtext><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msubsup><mml:mo>/</mml:mo><mml:msubsup><mml:mrow><mml:mi>L</mml:m","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"203 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135739351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2023-10-02DOI: 10.3389/fspas.2023.1199711
Katherine Goodrich, Ian J. Cohen, Steven Schwartz, Lynn B. Wilson, Drew Turner, Amir Caspi, Keith Smith, Randall Rose, Phyllis Whittlesey, Ferdinand Plaschke
Collisionless shock waves are one of the main mechanisms of energy conversion in space plasmas. They can directly or indirectly drive other universal plasma processes such as magnetic reconnection, turbulence, particle acceleration and wave phenomena. Collisionless shocks employ a myriad of kinetic plasma mechanisms to convert the kinetic energy of supersonic flows in space to other forms of energy (e.g., thermal plasma, energetic particles, or electromagnetic energy) in order for the flow to pass an immovable obstacle. The partitioning of energy downstream of collisionless shocks is not well understood, nor are the processes which perform energy conversion. While we, as the heliophysics community, have collected an abundance of observations of the terrestrial bow shock, instrument and mission-level limitations have made it impossible to quantify this partition, to establish the physics within the shock layer responsible for it, and to understand its dependence on upstream conditions. This paper stresses the need for the first ever spacecraft mission specifically designed and dedicated to the observation of both the terrestrial bow shock as well as Interplanetary shocks in the solar wind. Our mission concept, the Multi-point Assessment of the Kinematics of Shocks (MAKOS), will greatly improve on previous observations of the terrestrial bow shock with instrumentation specifically tailored to observe the evolution of the solar wind through the shock.
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Pub Date : 2023-09-29DOI: 10.3389/fspas.2023.1214612
Ivana Molina, Ludger Scherliess
Understanding the morphology and dynamics of the thermosphere is key to understanding the Earth’s upper atmosphere as a whole. Thermospheric winds play an important role in this process by transporting momentum and energy and affecting the composition, dynamics and morphology of not only the thermosphere but also of the ionosphere. The general morphology of the winds has been well established over the past decades, but we are only starting to understand its variability. In this process the lower atmosphere plays an important role due to direct penetration of waves from the lower atmosphere into the ionosphere/thermosphere, secondary waves generated on the way, or internal feedback mechanisms in the coupled ionosphere-thermosphere system. Therefore, knowledge about thermospheric variability and its causes is critical for an improved understanding of the global ionosphere-thermosphere system and its coupling to the lower atmosphere. We have used low-to mid-latitude zonal wind observations obtained by the Gravity Field and Steady-State Ocean Explorer (GOCE) satellite near 260 km altitude during geomagnetically quiet times to investigate the interannual and spatial zonal wind variability near dawn and dusk, during December solstice. The temporal and spatial variability is presented as a variation about the zonal mean values and decomposed into its underlying wavenumbers using a Fourier analysis. The obtained wave features are compared between different years and clear interannual changes are observed in the individual wave components, which appear to align with changes in the solar flux but do not correlate with variations in either El Niño Southern Oscillation or the Quasi Biennial Oscillation. The obtained wave features are compared and contrasted with results from the Climatological Tidal Model of the Thermosphere (CTMT) and revealed a very good agreement between CTMT and the 2009 and 2010 December GOCE zonal wind perturbations at dawn. However, during dusk, the CTMT zonal wind perturbations and in particular the zonal wave-1 component show significant differences with those observed by GOCE.
了解热层的形态和动力学是了解整个地球上层大气的关键。热层风通过传递动量和能量，影响热层和电离层的组成、动力学和形态，在这一过程中起着重要作用。在过去的几十年里，风的一般形态已经得到了很好的确立，但我们才刚刚开始了解它的可变性。在这一过程中，由于低层大气的波直接穿透电离层/热层，途中产生的二次波，或电离层-热层耦合系统的内部反馈机制，低层大气起着重要的作用。因此，了解热层变率及其原因对于提高对全球电离层-热层系统及其与低层大气耦合的理解至关重要。利用重力场和稳定状态海洋探测器(GOCE)卫星在260 km高度附近获得的低纬度至中纬度纬向风观测资料，研究了12月至日黎明和黄昏前后的年际和空间纬向风变化。时空变异性表现为纬向平均值的变化，并使用傅里叶分析将其分解为其底层波数。将获得的波特征在不同年份之间进行了比较，在单个波分量中观察到明显的年际变化，这些变化似乎与太阳通量的变化一致，但与El Niño南方涛动或准两年一次涛动的变化无关。将得到的波浪特征与CTMT (Climatological Tidal Model of Thermosphere)的结果进行了比较，发现CTMT与2009年和2010年12月GOCE的黎明纬向风扰动具有很好的一致性。然而，在黄昏期间，CTMT纬向风扰动，特别是纬向波-1分量与GOCE观测结果有显著差异。
{"title":"Longitudinal variability of thermospheric zonal winds near dawn and dusk","authors":"Ivana Molina, Ludger Scherliess","doi":"10.3389/fspas.2023.1214612","DOIUrl":"https://doi.org/10.3389/fspas.2023.1214612","url":null,"abstract":"Understanding the morphology and dynamics of the thermosphere is key to understanding the Earth’s upper atmosphere as a whole. Thermospheric winds play an important role in this process by transporting momentum and energy and affecting the composition, dynamics and morphology of not only the thermosphere but also of the ionosphere. The general morphology of the winds has been well established over the past decades, but we are only starting to understand its variability. In this process the lower atmosphere plays an important role due to direct penetration of waves from the lower atmosphere into the ionosphere/thermosphere, secondary waves generated on the way, or internal feedback mechanisms in the coupled ionosphere-thermosphere system. Therefore, knowledge about thermospheric variability and its causes is critical for an improved understanding of the global ionosphere-thermosphere system and its coupling to the lower atmosphere. We have used low-to mid-latitude zonal wind observations obtained by the Gravity Field and Steady-State Ocean Explorer (GOCE) satellite near 260 km altitude during geomagnetically quiet times to investigate the interannual and spatial zonal wind variability near dawn and dusk, during December solstice. The temporal and spatial variability is presented as a variation about the zonal mean values and decomposed into its underlying wavenumbers using a Fourier analysis. The obtained wave features are compared between different years and clear interannual changes are observed in the individual wave components, which appear to align with changes in the solar flux but do not correlate with variations in either El Niño Southern Oscillation or the Quasi Biennial Oscillation. The obtained wave features are compared and contrasted with results from the Climatological Tidal Model of the Thermosphere (CTMT) and revealed a very good agreement between CTMT and the 2009 and 2010 December GOCE zonal wind perturbations at dawn. However, during dusk, the CTMT zonal wind perturbations and in particular the zonal wave-1 component show significant differences with those observed by GOCE.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135245969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2023-09-29DOI: 10.3389/fspas.2023.1282261
Jens Oberheide, Stone M. Gardner, Mukta Neogi
NASA’s Geospace Dynamics Constellation (GDC) mission is a six satellite constellation to make in situ measurements of important ionospheric and thermospheric variables to better understand the processes that govern Earth’s near space environment. Scheduled for a 2029 launch into high inclination orbits ∼82° at ∼380 km, the satellite orbit planes will separate over time to provide almost continuous local solar time coverage every day towards the end of the 3 year baseline GDC mission. As such, the neutral temperature and neutral wind measurements of GDC will likely allow the heliophysics community to make significant progress towards resolving the tidal weather of the thermosphere, that is, day-to-day tidal variability, and how it is driven by meteorological processes near the surface and in situ forcing in the ionosphere-thermosphere system. To assess the GDC ability to accurately resolve the tides each day and when in the mission this can be achieved, we conduct an Observational Simulation System Experiment (OSSE) using SD-WACCM-X and the predicted GDC orbits. Our results show that GDC can provide closure on the tidal variability (mean, diurnal and semidiurnal, migrating and nonmigrating) at orbit height in mission phase 4 and throughout most parts of mission phase 3. We also perform Hough Mode Extension fitting of relevant tidal components to study possible connections between the GDC observations and the tides at 200 km, to assess synergies between GDC and the forthcoming DYNAMIC mission (scheduled to be co-launched with GDC) that will measure altitude-resolved winds and temperatures in the ∼100–200 km height range.
{"title":"Resolving the tidal weather of the thermosphere using GDC","authors":"Jens Oberheide, Stone M. Gardner, Mukta Neogi","doi":"10.3389/fspas.2023.1282261","DOIUrl":"https://doi.org/10.3389/fspas.2023.1282261","url":null,"abstract":"NASA’s Geospace Dynamics Constellation (GDC) mission is a six satellite constellation to make in situ measurements of important ionospheric and thermospheric variables to better understand the processes that govern Earth’s near space environment. Scheduled for a 2029 launch into high inclination orbits <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m1\"><mml:mo>∼</mml:mo><mml:mn>82</mml:mn><mml:mo>°</mml:mo></mml:math> at <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m2\"><mml:mo>∼</mml:mo><mml:mn>380</mml:mn></mml:math> km, the satellite orbit planes will separate over time to provide almost continuous local solar time coverage every day towards the end of the 3 year baseline GDC mission. As such, the neutral temperature and neutral wind measurements of GDC will likely allow the heliophysics community to make significant progress towards resolving the tidal weather of the thermosphere, that is, day-to-day tidal variability, and how it is driven by meteorological processes near the surface and in situ forcing in the ionosphere-thermosphere system. To assess the GDC ability to accurately resolve the tides each day and when in the mission this can be achieved, we conduct an Observational Simulation System Experiment (OSSE) using SD-WACCM-X and the predicted GDC orbits. Our results show that GDC can provide closure on the tidal variability (mean, diurnal and semidiurnal, migrating and nonmigrating) at orbit height in mission phase 4 and throughout most parts of mission phase 3. We also perform Hough Mode Extension fitting of relevant tidal components to study possible connections between the GDC observations and the tides at 200 km, to assess synergies between GDC and the forthcoming DYNAMIC mission (scheduled to be co-launched with GDC) that will measure altitude-resolved winds and temperatures in the ∼100–200 km height range.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135193316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2023-09-27DOI: 10.3389/fspas.2023.1260432
M. Cécere, A. Costa, H. Cremades, G. Stenborg
It has been shown that the magnetic structures surrounding coronal mass ejection (CME) events play a crucial role in their development and evolution along the first few solar radii. In particular, active regions, coronal holes, pseudostreamers, and helmet streamers are among the main coronal structures involved in the deviation of the trajectory of CMEs from their radial direction. Therefore, comprehensive observational studies along with their theoretical interpretation, aided by numerical simulations of the early evolution of CMEs, are the key ingredients to help determine their 3D trajectory in the interplanetary medium to narrow down the error in the estimation of the time of arrival of geoeffective events. In this mini-review, we compile the last decade of theoretical, numerical, and observational research that has shed light on the causes influencing the early deflection of CMEs away from their otherwise radial trajectory.
{"title":"Recent insights on CME deflections at low heights","authors":"M. Cécere, A. Costa, H. Cremades, G. Stenborg","doi":"10.3389/fspas.2023.1260432","DOIUrl":"https://doi.org/10.3389/fspas.2023.1260432","url":null,"abstract":"It has been shown that the magnetic structures surrounding coronal mass ejection (CME) events play a crucial role in their development and evolution along the first few solar radii. In particular, active regions, coronal holes, pseudostreamers, and helmet streamers are among the main coronal structures involved in the deviation of the trajectory of CMEs from their radial direction. Therefore, comprehensive observational studies along with their theoretical interpretation, aided by numerical simulations of the early evolution of CMEs, are the key ingredients to help determine their 3D trajectory in the interplanetary medium to narrow down the error in the estimation of the time of arrival of geoeffective events. In this mini-review, we compile the last decade of theoretical, numerical, and observational research that has shed light on the causes influencing the early deflection of CMEs away from their otherwise radial trajectory.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135582137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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