Frontiers in Astronomy and Space Sciences最新文献

{"title":"Ion kinetic effects linked to magnetic field discontinuities in the slow Alfvénic wind observed by Solar Orbiter in the inner heliosphere","authors":"Denise Perrone, Adriana Settino, Rossana De Marco, Raffaella D’Amicis, Silvia Perri","doi":"10.3389/fspas.2023.1250219","DOIUrl":"https://doi.org/10.3389/fspas.2023.1250219","url":null,"abstract":"Slow solar wind, sharing magnetic and plasma properties typical of fast wind, the so-called slow Alfvénic wind, has been widely observed in the heliosphere. Here, we report an analysis of the turbulent properties of a slow Alfvénic stream observed by Solar Orbiter at 0.64 AU. This solar wind stream is characterized by well distinguishable regions, namely, a main portion, an intermediate region, and a rarefaction region. Each of those intervals have been studied separately, in order to enhance similarities and differences in their turbulence properties. Coherent structures naturally emerge over different time/spatial scales and their characteristics at ion scales have been investigated. The presence of these intermittent events have been found to be closely related to kinetic features in the ion (both proton and alpha particles) velocity distribution functions, suggesting a fundamental role in the kinetic physical processes that mediate the sub-ion turbulence cascade.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135635586","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}

{"title":"The evolution of our understanding of coronal mass ejections","authors":"Russell A. Howard, Angelos Vourlidas, Guillermo Stenborg","doi":"10.3389/fspas.2023.1264226","DOIUrl":"https://doi.org/10.3389/fspas.2023.1264226","url":null,"abstract":"The unexpected observation of a sudden expulsion of mass through the solar corona in 1971 opened up a new field of interest in solar and stellar physics. The discovery came from a white-light coronagraph, which creates an artificial eclipse of the Sun, enabling the viewing of the faint glow from the corona. This observation was followed by many more observations and new missions. In the five decades since that discovery, there have been five generations of coronagraphs, each with improved performance, enabling continued understanding of the phenomena, which became known as Coronal Mass Ejection (CME) events. The conceptualization of the CME structure evolved from the elementary 2-dimensional loop to basically two fundamental types: a 3-dimensional magnetic flux rope and a non-magnetic eruption from pseudo-streamers. The former persists to 1 AU and beyond, whereas the latter dissipates by 15 R ⊙ . Historically, most of the studies have been devoted to understanding the CME large-scale structure and its associations, but this is changing. With the advent of the fourth and fifth coronagraph generations, more attention is being devoted to the their internal structure and initiation mechanisms. In this review, we describe the evolution of CME observations and their associations with other solar and heliospheric phenomena, with one of the more important correlations being its recognition as a driver of space-weather. We conclude with a brief overview of open questions and present some ideas for future observations.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135973768","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}

{"title":"Progress and prospects for research on Martian topographic features and typical landform identification","authors":"Liu Danyang, Cheng Weiming","doi":"10.3389/fspas.2023.1275516","DOIUrl":"https://doi.org/10.3389/fspas.2023.1275516","url":null,"abstract":"The study of Martian surface topography is important for understanding the geological evolution of Mars and revealing the spatial differentiation of the Martian landscape. Identifying typical landform units is a fundamental task when studying the origin and evolution of Mars and provides important information for landing on and exploring Mars, as well as estimating the age of the Martian surface and inferring the evolution of the Earth’s environment. In this paper, we first investigate Mars exploration, data acquisition and mapping, and the classification methods of Martian landforms. Then, the identification of several typical Martian landform types, such as aeolian landforms, fluvial landforms, and impact landforms, is shown in detail. Finally, the prospects of Mars data acquisition, landform mapping, and the construction and identification of the Martian landform classification system are presented. The construction of the Martian landform classification system and the identification of typical Martian landforms using deep learning are important development directions in planetary science.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135934239","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}

{"title":"Terrestrial impact sites as field analogs for planetary exploration","authors":"Philippe Lambert, Wolf Uwe Reimold","doi":"10.3389/fspas.2023.1186173","DOIUrl":"https://doi.org/10.3389/fspas.2023.1186173","url":null,"abstract":"Terrestrial impact structures provide the only analogs for hands-on astronaut training or robotic exercises in preparation for fieldwork on other planetary surfaces. Impact structures not only represent the dominant surface features on, inter alia , the Moon, Mars, or asteroids but are also crucial for basic geoscientific surface analysis, subsurface geological studies, and analysis of sites of possible exobiological evidence or economic resources for future colonization of other planetary bodies. We assess 11 terrestrial impact structures of varied age, type, size, and erosion level, the majority of which have already served for astronaut or geoscientist/student training purposes, for their suitability as possible impact geological training sites. This evaluation is achieved through a range of (1) practical criteria (such as access time and site infrastructure) and (2) geological criteria (such as impact geology, target geology, aspects of impact cratering, outcrop conditions, and variety). For the practical criteria, Ries, Rochechouart, and Steinheim score the highest, with a small advantage for Ries. Sudbury and Meteor Crater score similarly, yet much lower than the leaders, with Vredefort in between. Talemzane and Araguainha are just below Meteor Crater. Clearwater West, Haughton, and Mistastin are by far the least suitable ones. Regarding geological criteria, the scores vary much less. The three Northern Canada structures and Steinheim are at the end of the record, yet only 23%–39% below Ries, which comes out as the leader and is closely followed by Araguainha (only 2% below Ries). Although the Northern Canada sites compare in size and type to the younger and less eroded Ries and the Araguainha (older and more eroded) structures, the diversity of impact features and lithologies and the outcrop situation are less favorable. Considering only the geological features and lithologies factors, Rochechouart gets the highest mark, followed by Araguainha, Sudbury, Vredefort, and Ries. In view of the targeted objective, the analog testing experiment places Ries and Rochechouart in the first and second positions, respectively. Steinheim and Vredefort score almost the same in the third and fourth positions, respectively. The three Northern Canada sites score the lowest. Based on their accessibility, relative proximity to each other, and remarkable complementarity in terms of crater type and size, and in terms of impact and target features and lithologies, the combination of the three leading structures (Ries–Rochechouart–Steinheim) may represent the most appropriate target for analog training purposes, from anywhere in the world.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136103598","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}

{"title":"Biosignature preparation for ocean worlds (BioPOW) instrument prototype","authors":"Korine A. Duval, Tessa B. Van Volkenburg, Kathleen L. Craft, Chanel M. Person, John S. Harshman, Diarny O. Fernandes, Jennifer S. Benzing, Emil G. McDowell, Tyler W. Nelson, Gautham S. Divakar, Owen M. Pochettino, Mark E. Perry, Christopher E. Bradburne","doi":"10.3389/fspas.2023.1244682","DOIUrl":"https://doi.org/10.3389/fspas.2023.1244682","url":null,"abstract":"In situ sampling missions to detect biosignatures on ocean worlds requires thorough sample preparation to manage the expected chemical complexity of such environments. Proposed instruments must be capable of automatic liquid sample handling to ensure sensitive and accurate detections of biosignatures, regardless of the initial chemical composition. Herein, we outline the design, build, and test of the integrated Biosignature Preparation for Ocean Worlds (BioPOW) system capable of purifying amino acids from icy samples. This four step modular instrument 1) melts ice samples, 2) purifies amino acids via cation exchange chromatography, 3) concentrates via vacuum drying, and 4) derivatizes amino acids to volatilize and enable detection with downstream analytical instruments. Initial experiments validated the thermal performance of the system by melting ice in the sample cup (1 mL sample, 3°C–28°C, <5 min, 1.4 kJ) and heating the derivatization tank past the concentration temperature (20°C–60°C, 12 min, 3.6 kJ) to the derivatization temperature (60°C–90°C, 25 min, 7.5 kJ). Later experiments investigated important factors for automatic cation exchange using a design of experiments approach, and found that initial salt concentration, sample and eluate flow rates, and water wash volumes all play significant roles in reducing conductivity (1.1 x–6.7 x) while maintaining phenylalanine yields between 31% and 94%. The modules were then integrated into a 12 cm × 20 cm × 20 cm fieldable platform for analysis, and the maturation of this design for future spaceflight is discussed.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134906534","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}

{"title":"cavsiopy: a Python package to calculate and visualize spacecraft instrument orientation","authors":"E. Ceren Kalafatoglu Eyiguler, Warren Holley, Andrew D. Howarth, Donald W. Danskin, Kuldeep Pandey, Carley J. Martin, Robert G. Gillies, Andrew W. Yau, Glenn C. Hussey","doi":"10.3389/fspas.2023.1278794","DOIUrl":"https://doi.org/10.3389/fspas.2023.1278794","url":null,"abstract":"Spacecraft attitude plays an important role in the observations of various atmospheric, planetary, and terrestrial parameters and phenomena that are of interest to the scientific community. Precise measurements from imagers, particle sensors, and antennas require accurate knowledge of instrument orientation. cavsiopy is an easy-to-install and use, light-weight open-source Python package for researchers who need to consider instrument pointing direction and observation geometry. cavsiopy contains the coordinate transformation routines and the corresponding rotation matrices from the spacecraft orbital reference frame (ORF) to any of the geocentric equatorial inertial for epoch J2000 (GEI J2K)/International Celestial Reference Frame (ICRF), Earth-centered, Earth-fixed (ECEF), International Terrestrial Reference Frame (ITRF), geodetic north-east-down, and geocentric north-east-center coordinate systems. Additionally, cavsiopy includes routines for importing Swarm-E ephemeris and generic two-line-element (TLE) data files; for the calculation of spacecraft azimuth, elevation, and orbital parameters; as well as for the 2D/3D visualization of the geometry between the instrument and the target. Functionality and utilization of cavsiopy for research problems are demonstrated with examples and visualizations for the Radio Receiver Instrument (RRI) and the Fast Auroral Imager (FAI) of e-POP/Swarm-E.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136382166","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}

{"title":"Corrigendum: Magnetic field reconstruction for a realistic multi-point, multi-scale spacecraft observatory","authors":"T. Broeren, K. G. Klein, J. M. TenBarge, Ivan Dors, O. W. Roberts, D. Verscharen","doi":"10.3389/fspas.2023.1197352","DOIUrl":"https://doi.org/10.3389/fspas.2023.1197352","url":null,"abstract":"","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135321850","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}

{"title":"Responses of the wintertime auroral E-region neutral wind to varying levels of geomagnetic activity","authors":"Weijia Zhan, Stephen R. Keappler","doi":"10.3389/fspas.2023.1282724","DOIUrl":"https://doi.org/10.3389/fspas.2023.1282724","url":null,"abstract":"Introduction: The auroral E-region is an important interface where forces from the magnetosphere and the lower atmosphere converge and have a significant effect on the vertical structure of the neutral winds. The resulting vertical neutral wind structure has been reported to be associated with altitude-dependent and nonlinear effects from different forces. We conduct a statistical examination of the reactions of wintertime neutral winds to four various degrees of geomagnetic activity, with a focus on the impacts of ion drag. Methods: We derive neutral winds using the PFISR measurements covering 2010–2019 and will give a statistical view of the auroral E-region neutral wind with a focus on the winter nighttime during different disturbed conditions. We investigate the effects of the geomagnetic activity on the neutral winds and the tidal components by dividing the dataset into 4 subsets. Tidal decomposition is conducted by least square fitting of the seasonal median winds to obtain the mean, diurnal amplitude, diurnal phase, semidiurnal amplitude, and semidiurnal phase. Results and discussion: We find that 1) when geomagnetic activity increases, dawn-dusk asymmetry exists in both zonal and meridional winds in the upper E-region with stronger zonal wind in the dusk sector than in the dawn sector and much stronger meridional wind in the dawn sector than in the dusk sector. 2) Tidal decomposition results reveal that geomagnetic activity has more significant effects on the meridional diurnal amplitude than zonal diurnal amplitude while the zonal and meridional semidiurnal amplitudes show similar changes when the geomagnetic activity increases. In addition, the maximum semidiurnal amplitude, particularly in the zonal direction, appears at a higher altitude with larger values as geomagnetic activity increases, indicating an ascending transition altitude for the semidiurnal oscillations. The ascending trend of maximum semidiurnal amplitude appearing at higher altitudes during more disturbed conditions has not been reported before. 3) Zonal wind over 110 km demonstrates increasing ion drag effects in the evening sector and the effects of coupled ion drag and other factors after midnight.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135366487","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}

{"title":"The saturation mechanism of thermal instability","authors":"Tim Waters, Daniel Proga","doi":"10.3389/fspas.2023.1198135","DOIUrl":"https://doi.org/10.3389/fspas.2023.1198135","url":null,"abstract":"The literature on thermal instability (TI) reveals that even for a simple homogeneous plasma, the nonlinear outcome ranges from a gentle reconfiguration of the initial state to an explosive one, depending on whether the condensations that form evolve in an isobaric or nonisobaric manner. After summarizing the recent developments on the linear and nonlinear theory of TI, here we derive several general identities from the evolution equation for entropy that reveal the mechanism by which TI saturates; whenever the boundary of the instability region (the Balbus contour) is crossed, a dynamical change is triggered that causes the comoving time derivative of the pressure to change the sign. This event implies that the gas pressure force reverses direction, slowing the continued growth of condensation. For isobaric evolution, this “pressure reversal” occurs nearly simultaneously for every fluid element in condensation and a steady state is quickly reached. For nonisobaric evolution, the condensation is no longer in mechanical equilibrium and the contracting gas rebounds with greater force during the expansion phase that accompanies the gas reaching the equilibrium curve. The cloud then pulsates because the return to mechanical equilibrium becomes wave mediated. We show that both the contraction rebound event and subsequent pulsation behavior follow analytically from an analysis of the new identities. Our analysis also leads to the identification of an isochoric TI zone and makes it clear that unless this zone intersects the equilibrium curve, isochoric modes can only become unstable if the plasma is in a state of thermal non-equilibrium.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136113755","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}

{"title":"A possible mechanism for the formation of an eastward moving auroral spiral","authors":"Katharina N. Maetschke, Elena A. Kronberg, Noora Partamies, Elena E. Grigorenko","doi":"10.3389/fspas.2023.1240081","DOIUrl":"https://doi.org/10.3389/fspas.2023.1240081","url":null,"abstract":"The generation process of auroral spirals is described by different theories varying for their morphology and surrounding conditions. Here, a possible mechanism is proposed for an eastward moving auroral spiral, which was observed in Tromsø, Norway, during the expansion phase of a substorm on 18 September 2013. Measurements from the THEMIS-A and Cluster spacecraft were analyzed, which were located up to ∼10 R E duskward from the spiral generator region in the magnetosphere. Precursory to the spiral observation, concurrent magnetic field dipolarizations, flow bursts and electron injections were measured by the Cluster satellites between 13.6 and 14.2 R E radial distance from Earth. A local Kelvin-Helmholtz-like vortex street in the magnetic field was detected at the same time, which was likely caused by bursty bulk flows. The vortex street was oriented approximately in the X-Y (GSE) plane and presumably propagated towards the source region of the spiral due to a high dawnward velocity component in the flow bursts. The observations suggest that the spiral can have been generated by an associated vortex in the magnetotail and then mapped along the magnetic field lines to the ionosphere. To better understand the role of the ionosphere in auroral spiral generation, in future more mesoscale observations are required.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135854182","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}