Pub Date : 2023-09-15DOI: 10.3389/fspas.2023.1186172
Martin Ferus, Antonín Knížek, Giuseppe Cassone, Paul B. Rimmer, Hitesh Changela, Elias Chatzitheodoridis, Inna Uwarova, Ján Žabka, Petr Kabáth, Franz Saija, Homa Saeidfirozeh, Libor Lenža, Miroslav Krůs, Lukáš Petera, Lukáš Nejdl, Petr Kubelík, Anna Křivková, David Černý, Martin Divoký, Michael Pisařík, Tomáš Kohout, Lakshika Palamakumbure, Barbora Drtinová, Klára Hlouchová, Nikola Schmidt, Zita Martins, Jorge Yáñez, Svatopoluk Civiš, Pavel Pořízka, Tomáš Mocek, Jona Petri, Sabine Klinkner
Meteor plasmas and impact events are complex, dynamic natural phenomena. Simulating these processes in the laboratory is, however, a challenge. The technique of laser induced dielectric breakdown was first used for this purpose almost 50 years ago. Since then, laser-based experiments have helped to simulate high energy processes in the Tunguska and Chicxulub impact events, heavy bombardment on the early Earth, prebiotic chemical evolution, space weathering of celestial bodies and meteor plasma. This review summarizes the current level of knowledge and outlines possible paths of future development.
{"title":"Simulating asteroid impacts and meteor events by high-power lasers: from the laboratory to spaceborne missions","authors":"Martin Ferus, Antonín Knížek, Giuseppe Cassone, Paul B. Rimmer, Hitesh Changela, Elias Chatzitheodoridis, Inna Uwarova, Ján Žabka, Petr Kabáth, Franz Saija, Homa Saeidfirozeh, Libor Lenža, Miroslav Krůs, Lukáš Petera, Lukáš Nejdl, Petr Kubelík, Anna Křivková, David Černý, Martin Divoký, Michael Pisařík, Tomáš Kohout, Lakshika Palamakumbure, Barbora Drtinová, Klára Hlouchová, Nikola Schmidt, Zita Martins, Jorge Yáñez, Svatopoluk Civiš, Pavel Pořízka, Tomáš Mocek, Jona Petri, Sabine Klinkner","doi":"10.3389/fspas.2023.1186172","DOIUrl":"https://doi.org/10.3389/fspas.2023.1186172","url":null,"abstract":"Meteor plasmas and impact events are complex, dynamic natural phenomena. Simulating these processes in the laboratory is, however, a challenge. The technique of laser induced dielectric breakdown was first used for this purpose almost 50 years ago. Since then, laser-based experiments have helped to simulate high energy processes in the Tunguska and Chicxulub impact events, heavy bombardment on the early Earth, prebiotic chemical evolution, space weathering of celestial bodies and meteor plasma. This review summarizes the current level of knowledge and outlines possible paths of future development.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135439634","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}
SiRGraF Integrated Tool for Coronal dynaMics (SITCoM) is based on the Simple Radial Gradient Filter used to filter the radial gradient in the white-light coronagraph images and bring out dynamic structures. SITCoM has been developed in Python and integrated with SunPy and can be installed by users with the command pip install sitcom. This enables the user to pass the white-light coronagraph data to the tool and generate radially filtered output with an option to save in various formats as required. We implemented the functionality of tracking the transients such as coronal mass ejections, outflows, and plasma blobs, using height–time plots and deriving their kinematics. In addition, SITCoM also supports oscillation and wave studies such as for streamer waves. This is performed by creating a distance–time plot at a user-defined location (artificial slice) and fitting a sinusoidal function to derive the properties of waves, such as time period, amplitude, and damping time (if any). We provide the option to manually or automatically select the data points to be used for fitting. SITCoM is a tool to analyze some properties of coronal dynamics quickly. We present an overview of the SITCoM with the applications for deriving coronal dynamics’ kinematics and oscillation properties. We discuss the limitations of this tool along with prospects for future improvement.
{"title":"SITCoM: SiRGraF Integrated Tool for Coronal dynaMics","authors":"Purvi Udhwani, Arpit Kumar Shrivastav, Ritesh Patel","doi":"10.3389/fspas.2023.1227872","DOIUrl":"https://doi.org/10.3389/fspas.2023.1227872","url":null,"abstract":"SiRGraF Integrated Tool for Coronal dynaMics (SITCoM) is based on the Simple Radial Gradient Filter used to filter the radial gradient in the white-light coronagraph images and bring out dynamic structures. SITCoM has been developed in Python and integrated with SunPy and can be installed by users with the command pip install sitcom. This enables the user to pass the white-light coronagraph data to the tool and generate radially filtered output with an option to save in various formats as required. We implemented the functionality of tracking the transients such as coronal mass ejections, outflows, and plasma blobs, using height–time plots and deriving their kinematics. In addition, SITCoM also supports oscillation and wave studies such as for streamer waves. This is performed by creating a distance–time plot at a user-defined location (artificial slice) and fitting a sinusoidal function to derive the properties of waves, such as time period, amplitude, and damping time (if any). We provide the option to manually or automatically select the data points to be used for fitting. SITCoM is a tool to analyze some properties of coronal dynamics quickly. We present an overview of the SITCoM with the applications for deriving coronal dynamics’ kinematics and oscillation properties. We discuss the limitations of this tool along with prospects for future improvement.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135438484","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 : 2023-09-14DOI: 10.3389/fspas.2023.1214591
Ivana Molina, Ludger Scherliess
Winds in the thermosphere play an important role in the transport of momentum and energy in the upper atmosphere and affect the composition, dynamics and morphology of the ionospheric plasma. Although the general morphology of the winds is well understood, we are only starting to understand its variability. During the last decade it has become inherently clear that in addition to solar forcing of the thermosphere, the lower atmosphere also is an important driver of thermospheric variability. Therefore, an understanding of thermospheric variability and its spatial and temporal correlations is critical for an improved understanding of the coupled ionosphere-thermosphere system and the coupling to the lower atmosphere. The Gravity Field and Steady-State Ocean Explorer (GOCE) provided zonal winds near dawn and dusk at an altitude of around 260 km from November 2009 to October 2013. We have used GOCE zonal wind observations from low- to mid-latitudes obtained during geomagnetically quiet times to investigate spatial and temporal correlations in the zonal winds near dawn and dusk. Latitudinal correlations were calculated for the GOCE zonal winds for December solstice separately for each year from 2009 to 2012 and their year-to-year variation was established. Correlations between hemispheric conjugate points were found at mid latitudes during the latter years. Latitudinal correlations for December solstice 2009 and June solstice 2010 were compared and the correlation length was found to be consistently larger in the winter hemisphere during dawn and in the summer hemisphere during dusk. Zonal wind longitudinal/temporal correlations were also determined for December 2009 and 2011 and for June 2010 and found to be periodic in longitude/time. The temporal evolution of the temporal/longitudinal correlations were found to gradually decrease over the course of several days. The maxima in the correlation coefficients were always located in the winter hemisphere during dawn and in the summer hemisphere during dusk. During dawn, the largest contributors to the temporal/longitudinal correlations were found to be nonmigrating tides, whereas during dusk, additional waves appear to play important roles.
{"title":"Spatial and temporal correlations of thermospheric zonal winds from GOCE satellite observations","authors":"Ivana Molina, Ludger Scherliess","doi":"10.3389/fspas.2023.1214591","DOIUrl":"https://doi.org/10.3389/fspas.2023.1214591","url":null,"abstract":"Winds in the thermosphere play an important role in the transport of momentum and energy in the upper atmosphere and affect the composition, dynamics and morphology of the ionospheric plasma. Although the general morphology of the winds is well understood, we are only starting to understand its variability. During the last decade it has become inherently clear that in addition to solar forcing of the thermosphere, the lower atmosphere also is an important driver of thermospheric variability. Therefore, an understanding of thermospheric variability and its spatial and temporal correlations is critical for an improved understanding of the coupled ionosphere-thermosphere system and the coupling to the lower atmosphere. The Gravity Field and Steady-State Ocean Explorer (GOCE) provided zonal winds near dawn and dusk at an altitude of around 260 km from November 2009 to October 2013. We have used GOCE zonal wind observations from low- to mid-latitudes obtained during geomagnetically quiet times to investigate spatial and temporal correlations in the zonal winds near dawn and dusk. Latitudinal correlations were calculated for the GOCE zonal winds for December solstice separately for each year from 2009 to 2012 and their year-to-year variation was established. Correlations between hemispheric conjugate points were found at mid latitudes during the latter years. Latitudinal correlations for December solstice 2009 and June solstice 2010 were compared and the correlation length was found to be consistently larger in the winter hemisphere during dawn and in the summer hemisphere during dusk. Zonal wind longitudinal/temporal correlations were also determined for December 2009 and 2011 and for June 2010 and found to be periodic in longitude/time. The temporal evolution of the temporal/longitudinal correlations were found to gradually decrease over the course of several days. The maxima in the correlation coefficients were always located in the winter hemisphere during dawn and in the summer hemisphere during dusk. During dawn, the largest contributors to the temporal/longitudinal correlations were found to be nonmigrating tides, whereas during dusk, additional waves appear to play important roles.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135489312","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 : 2023-09-14DOI: 10.3389/fspas.2023.1266750
L. A. Balona
High-precision photometry from TESS has revealed over 500 stars, located between the δ Scuti and β Cephei instability strips, which pulsate with high frequencies. Models do not predict high pulsation frequencies in these stars. These anomalous variables may be identified with the historical “Maia” variables. From the projected rotational velocities, it is shown that the rotation rates of Maia variables are no different from main sequence or SPB stars in the same effective temperature range. Some Maia stars pulsate at frequencies typical of roAp stars. It is shown that Maia stars should be considered an extension of δ Scuti variables to effective temperatures as high as 18,000 K, rather than as a separate class. The TESS data show a continuous sequence of low-frequency pulsating stars linking the γ Doradus and SPB variables, which is not predicted by the models. There are, in fact, no well-defined instability strips at all among upper main sequence stars, which means that arbitrary choices of effective temperature and frequency ranges need to be made in order to assign a particular variability class. It seems that a mixture of driving mechanisms is present in which convection may play a very important role.
{"title":"Maia variables and other anomalies among pulsating stars","authors":"L. A. Balona","doi":"10.3389/fspas.2023.1266750","DOIUrl":"https://doi.org/10.3389/fspas.2023.1266750","url":null,"abstract":"High-precision photometry from TESS has revealed over 500 stars, located between the δ Scuti and β Cephei instability strips, which pulsate with high frequencies. Models do not predict high pulsation frequencies in these stars. These anomalous variables may be identified with the historical “Maia” variables. From the projected rotational velocities, it is shown that the rotation rates of Maia variables are no different from main sequence or SPB stars in the same effective temperature range. Some Maia stars pulsate at frequencies typical of roAp stars. It is shown that Maia stars should be considered an extension of δ Scuti variables to effective temperatures as high as 18,000 K, rather than as a separate class. The TESS data show a continuous sequence of low-frequency pulsating stars linking the γ Doradus and SPB variables, which is not predicted by the models. There are, in fact, no well-defined instability strips at all among upper main sequence stars, which means that arbitrary choices of effective temperature and frequency ranges need to be made in order to assign a particular variability class. It seems that a mixture of driving mechanisms is present in which convection may play a very important role.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134912850","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 : 2023-09-13DOI: 10.3389/fspas.2023.1162624
T. M. Esman, J. R. Espley, J. R. Gruesbeck, A. Verbiscer, J. Giacalone, A. J. Halford
Schumann resonances are electromagnetic resonances generally associated with lightning. If they exist on Mars, Schumann resonances are expected to resonate within the ionospheric cavity at a fundamental frequency of 7–14 Hz. We conducted a search for 5–16 Hz signals below 400 km in magnetic field data from the Mars Global Surveyor (MGS) and Mars Atmosphere and Volatile Evolution (MAVEN) missions. Fast Fourier transforms and wavelet analysis were used to find these signals and investigate their characteristics further. We discuss our null results and the required steps forward to continue and improve this search. Future studies will require higher sensitivity instruments and would benefit from additional missions that reach into the lower ionosphere of Mars.
{"title":"Will we find Martian lightning via Schumann resonances?","authors":"T. M. Esman, J. R. Espley, J. R. Gruesbeck, A. Verbiscer, J. Giacalone, A. J. Halford","doi":"10.3389/fspas.2023.1162624","DOIUrl":"https://doi.org/10.3389/fspas.2023.1162624","url":null,"abstract":"Schumann resonances are electromagnetic resonances generally associated with lightning. If they exist on Mars, Schumann resonances are expected to resonate within the ionospheric cavity at a fundamental frequency of 7–14 Hz. We conducted a search for 5–16 Hz signals below 400 km in magnetic field data from the Mars Global Surveyor (MGS) and Mars Atmosphere and Volatile Evolution (MAVEN) missions. Fast Fourier transforms and wavelet analysis were used to find these signals and investigate their characteristics further. We discuss our null results and the required steps forward to continue and improve this search. Future studies will require higher sensitivity instruments and would benefit from additional missions that reach into the lower ionosphere of Mars.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135734782","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 so-called sporadic sodium layers (SSLs or Na S ) are proposed to be strongly related to wave fluctuations. The solitary wave is a particular solution of the partial differential equation whose energy travels as a localized wave packet. A soliton, on the other hand, is a special type of solitary wave that exhibits a particle-like behavior with a strong stable form. For the first time, the solitary wave theory has been used in this research to study the fine structure of SSL/Na S . We performed soliton fitting processes on the observed data from the Andes Lidar Observatory and found out that 24/27 Na S events had exhibited similar features/characteristics to a soliton. Time series of the net anomaly of the Na S revealed the same variation process to the solution of a generalized five-order KdV equation. Our results, therefore, suggested that the Na S phenomenon would be a pertinent tracer for non-linear wave studies in the atmosphere.
所谓的零星钠层(sls或Na S)被认为与波动密切相关。孤立波是偏微分方程的特解，其能量以局域波包的形式传播。另一方面，孤子是一种特殊类型的孤波，它表现出类似粒子的行为，具有很强的稳定形式。本研究首次利用孤立波理论研究了SSL/Na S的精细结构。我们对安第斯激光雷达观测数据进行了孤子拟合处理，发现24/27 Na S事件具有与孤子相似的特征。Na S净距平的时间序列对广义五阶KdV方程的解具有相同的变化过程。因此，我们的结果表明，Na S现象将是大气中非线性波研究的相关示踪剂。
{"title":"Solitary wave characteristics on the fine structure of the mesospheric sporadic sodium layer","authors":"Shican Qiu, Mengxi Shi, Hamad Yousof, Willie Soon, Mingjiao Jia, Xianghui Xue, Tao Li, Peng Ju, Xiankang Dou","doi":"10.3389/fspas.2023.1241663","DOIUrl":"https://doi.org/10.3389/fspas.2023.1241663","url":null,"abstract":"The so-called sporadic sodium layers (SSLs or Na S ) are proposed to be strongly related to wave fluctuations. The solitary wave is a particular solution of the partial differential equation whose energy travels as a localized wave packet. A soliton, on the other hand, is a special type of solitary wave that exhibits a particle-like behavior with a strong stable form. For the first time, the solitary wave theory has been used in this research to study the fine structure of SSL/Na S . We performed soliton fitting processes on the observed data from the Andes Lidar Observatory and found out that 24/27 Na S events had exhibited similar features/characteristics to a soliton. Time series of the net anomaly of the Na S revealed the same variation process to the solution of a generalized five-order KdV equation. Our results, therefore, suggested that the Na S phenomenon would be a pertinent tracer for non-linear wave studies in the atmosphere.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884356","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 : 2023-09-12DOI: 10.3389/fspas.2023.1255481
Tobias C. Hinse, Bertil F. Dorch, Lars V. T. Occhionero, Jakob P. Holck
The 450th anniversary of the discovery of the SN 1572 supernova event was celebrated in 2022. A closer look at the historical development of the field of supernova astronomy reveals the scientific importance of Tycho Brahe’s 1572 observations of this “new star.” In their quest to learn more about the new type of stellar explosion and subsequent evolution, the initial protagonists in this field (Baader and Zwicky among others) gradually turned their attention to the final remnant state of these supernova events. Since the remnant object thought to be associated with the extragalactic supernova event was found to be very dim, the focus quickly shifted toward nearby galactic events. It is at this point where Tycho Brahe’s observations played an important and often overlooked role in the context of the development of stellar evolution as a scientific field. Tycho Brahe’s meticulous and detailed recordings of the change in brightness of the new star not only allowed modern astronomers to classify SN 1572 as a supernova event but also helped them pinpoint the exact astrometric location of SN 1572. These findings helped to empirically link extragalactic supernova events to nearby past supernova remnants in the Milky Way. This enabled subsequent observations allowing further characterization. Transforming the historical recordings to a standardized photometric system also allowed the classification of SN 1572 as a type I supernova event.
{"title":"How Tycho Brahe’s recordings in 1572 support SN 1572 as a type I(a) supernova","authors":"Tobias C. Hinse, Bertil F. Dorch, Lars V. T. Occhionero, Jakob P. Holck","doi":"10.3389/fspas.2023.1255481","DOIUrl":"https://doi.org/10.3389/fspas.2023.1255481","url":null,"abstract":"The 450th anniversary of the discovery of the SN 1572 supernova event was celebrated in 2022. A closer look at the historical development of the field of supernova astronomy reveals the scientific importance of Tycho Brahe’s 1572 observations of this “new star.” In their quest to learn more about the new type of stellar explosion and subsequent evolution, the initial protagonists in this field (Baader and Zwicky among others) gradually turned their attention to the final remnant state of these supernova events. Since the remnant object thought to be associated with the extragalactic supernova event was found to be very dim, the focus quickly shifted toward nearby galactic events. It is at this point where Tycho Brahe’s observations played an important and often overlooked role in the context of the development of stellar evolution as a scientific field. Tycho Brahe’s meticulous and detailed recordings of the change in brightness of the new star not only allowed modern astronomers to classify SN 1572 as a supernova event but also helped them pinpoint the exact astrometric location of SN 1572. These findings helped to empirically link extragalactic supernova events to nearby past supernova remnants in the Milky Way. This enabled subsequent observations allowing further characterization. Transforming the historical recordings to a standardized photometric system also allowed the classification of SN 1572 as a type I supernova event.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135885923","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 kinematics of coronal mass ejections (CMEs) are crucial for understanding their initiation mechanism and predicting their impact on Earth and other planets. With most of the acceleration and deceleration occurring below 4 R ⊙ , capturing this phase is vital to better understand their initiation mechanism. Furthermore, the kinematics of CMEs in the inner corona ( < 3 R ⊙ ) are closely related to their propagation in the outer corona and their eventual impact on Earth. Since the kinematics of CMEs are mainly probed using coronagraph data, it is crucial to investigate the impact of imaging cadence on the precision of data analysis and the conclusions drawn from it and also for determining the flexibility of designing observational campaigns with upcoming coronagraphs. This study investigates the impact of imaging cadence on the kinematics of ten CMEs observed by the K-Coronagraph of the Mauna Loa Solar Observatory. We manually track the CMEs using high cadence (15 s) white-light observations of K-Cor and vary the cadence as 30 s, 1, 2, and 5 min to study the impact of cadence on the kinematics. We also employed the bootstrapping method to estimate the confidence interval of the fitting parameters. Our results indicate that the average velocity of the CMEs does not have a high dependence on the imaging cadence, while the average acceleration shows significant dependence on the same, with the confidence interval showing significant shifts for the average acceleration for different cadences. The impact of degraded cadence is also seen in the estimation of the time of onset of acceleration. We further find that it is difficult to find an optimum cadence to study all CMEs, as it is also influenced by the pixel resolution of the instrument and the speed of the CME. However, except for very slow CMEs (speeds less than 300 km −1 ), our results indicate a cadence of 1 min to be reasonable for the study of their kinematics. The results of this work will be important in the planning of observational campaigns for the existing and upcoming missions that will observe the inner corona.
{"title":"Exploring the impact of imaging cadence on inferring CME kinematics","authors":"Nitin Vashishtha, Satabdwa Majumdar, Ritesh Patel, Vaibhav Pant, Dipankar Banerjee","doi":"10.3389/fspas.2023.1232197","DOIUrl":"https://doi.org/10.3389/fspas.2023.1232197","url":null,"abstract":"The kinematics of coronal mass ejections (CMEs) are crucial for understanding their initiation mechanism and predicting their impact on Earth and other planets. With most of the acceleration and deceleration occurring below 4 R ⊙ , capturing this phase is vital to better understand their initiation mechanism. Furthermore, the kinematics of CMEs in the inner corona ( <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m1\"><mml:mo><</mml:mo></mml:math> 3 R ⊙ ) are closely related to their propagation in the outer corona and their eventual impact on Earth. Since the kinematics of CMEs are mainly probed using coronagraph data, it is crucial to investigate the impact of imaging cadence on the precision of data analysis and the conclusions drawn from it and also for determining the flexibility of designing observational campaigns with upcoming coronagraphs. This study investigates the impact of imaging cadence on the kinematics of ten CMEs observed by the K-Coronagraph of the Mauna Loa Solar Observatory. We manually track the CMEs using high cadence (15 s) white-light observations of K-Cor and vary the cadence as 30 s, 1, 2, and 5 min to study the impact of cadence on the kinematics. We also employed the bootstrapping method to estimate the confidence interval of the fitting parameters. Our results indicate that the average velocity of the CMEs does not have a high dependence on the imaging cadence, while the average acceleration shows significant dependence on the same, with the confidence interval showing significant shifts for the average acceleration for different cadences. The impact of degraded cadence is also seen in the estimation of the time of onset of acceleration. We further find that it is difficult to find an optimum cadence to study all CMEs, as it is also influenced by the pixel resolution of the instrument and the speed of the CME. However, except for very slow CMEs (speeds less than 300 km −1 ), our results indicate a cadence of 1 min to be reasonable for the study of their kinematics. The results of this work will be important in the planning of observational campaigns for the existing and upcoming missions that will observe the inner corona.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135886378","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}
Empirical models have been previously developed using the large dataset of satellite observations to obtain the global distributions of total electron density and whistler-mode wave power, which are important in modeling radiation belt dynamics. In this paper, we apply the empirical models to construct the total electron density and the wave amplitudes of chorus and hiss, and compare them with the observations along Van Allen Probes orbits to evaluate the model performance. The empirical models are constructed using the Hp30 and SME (or SML) indices. The total electron density model provides an overall high correlation coefficient with observations, while large deviations are found in the dynamic regions near the plasmapause or in the plumes. The chorus wave model generally agrees with observations when the plasma trough region is correctly modeled and for modest wave amplitudes of 10–100 pT. The model overestimates the wave amplitude when the chorus is not observed or weak, and underestimates the wave amplitude when a large-amplitude chorus is observed. Similarly, the hiss wave model has good performance inside the plasmasphere when modest wave amplitudes are observed. However, when the modeled plasmapause location does not agree with the observation, the model misidentifies the chorus and hiss waves compared to observations, and large modeling errors occur. In addition, strong (>200 pT) hiss waves are observed in the plumes, which are difficult to capture using the empirical model due to their transient nature and relatively poor sampling statistics. We also evaluate four metrics for different empirical models parameterized by different indices. Among the tested models, the empirical model considering a plasmapause and controlled by Hp* (the maximum Hp30 during the previous 24 h) and SME* (the maximum SME during the previous 3 h) or Hp* and SML has the best performance with low errors and high correlation coefficients. Our study indicates that the empirical models are applicable for predicting density and whistler-mode waves with modest power, but large errors could occur, especially near the highly-dynamic plasmapause or in the plumes.
{"title":"Evaluating the performance of empirical models of total electron density and whistler-mode wave amplitude in the Earth’s inner magnetosphere","authors":"Qianli Ma, Xiangning Chu, Donglai Ma, Sheng Huang, Wen Li, Jacob Bortnik, Xiao-Chen Shen","doi":"10.3389/fspas.2023.1232702","DOIUrl":"https://doi.org/10.3389/fspas.2023.1232702","url":null,"abstract":"Empirical models have been previously developed using the large dataset of satellite observations to obtain the global distributions of total electron density and whistler-mode wave power, which are important in modeling radiation belt dynamics. In this paper, we apply the empirical models to construct the total electron density and the wave amplitudes of chorus and hiss, and compare them with the observations along Van Allen Probes orbits to evaluate the model performance. The empirical models are constructed using the Hp30 and SME (or SML) indices. The total electron density model provides an overall high correlation coefficient with observations, while large deviations are found in the dynamic regions near the plasmapause or in the plumes. The chorus wave model generally agrees with observations when the plasma trough region is correctly modeled and for modest wave amplitudes of 10–100 pT. The model overestimates the wave amplitude when the chorus is not observed or weak, and underestimates the wave amplitude when a large-amplitude chorus is observed. Similarly, the hiss wave model has good performance inside the plasmasphere when modest wave amplitudes are observed. However, when the modeled plasmapause location does not agree with the observation, the model misidentifies the chorus and hiss waves compared to observations, and large modeling errors occur. In addition, strong (&gt;200 pT) hiss waves are observed in the plumes, which are difficult to capture using the empirical model due to their transient nature and relatively poor sampling statistics. We also evaluate four metrics for different empirical models parameterized by different indices. Among the tested models, the empirical model considering a plasmapause and controlled by Hp* (the maximum Hp30 during the previous 24 h) and SME* (the maximum SME during the previous 3 h) or Hp* and SML has the best performance with low errors and high correlation coefficients. Our study indicates that the empirical models are applicable for predicting density and whistler-mode waves with modest power, but large errors could occur, especially near the highly-dynamic plasmapause or in the plumes.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135982329","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 : 2023-09-08DOI: 10.3389/fspas.2023.1228901
Michael S. Smith, Ramona L. Vogt, K. Label
Understanding the harmful effects of galactic cosmic rays (GCRs) on space exploration requires a substantial amount of nuclear data. Specifically, the interaction of energetic GCR charged particles with spacecraft materials generates secondary radiations that, through energy deposition, can harm astronauts and electronic systems. By identifying the gaps in our knowledge of the relevant nuclear data—such as interaction cross sections—and identifying ways to fill those gaps—with measurements, compilations, evaluations, dissemination, reaction modeling, sensitivity studies, and uncertainty quantification—the safety and viability of space exploration can be improved. This work surveys the state of the art in this interdisciplinary field and identifies promising collaborative research topics that have significant potential to advance our understanding of the effects of the space radiation environment on space exploration.
{"title":"Nuclear data for space exploration","authors":"Michael S. Smith, Ramona L. Vogt, K. Label","doi":"10.3389/fspas.2023.1228901","DOIUrl":"https://doi.org/10.3389/fspas.2023.1228901","url":null,"abstract":"Understanding the harmful effects of galactic cosmic rays (GCRs) on space exploration requires a substantial amount of nuclear data. Specifically, the interaction of energetic GCR charged particles with spacecraft materials generates secondary radiations that, through energy deposition, can harm astronauts and electronic systems. By identifying the gaps in our knowledge of the relevant nuclear data—such as interaction cross sections—and identifying ways to fill those gaps—with measurements, compilations, evaluations, dissemination, reaction modeling, sensitivity studies, and uncertainty quantification—the safety and viability of space exploration can be improved. This work surveys the state of the art in this interdisciplinary field and identifies promising collaborative research topics that have significant potential to advance our understanding of the effects of the space radiation environment on space exploration.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48230849","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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