Frontiers in Astronomy and Space Sciences最新文献_第2页

Improved models for estimating sporadic-E intensity from GNSS radio occultation measurements 从全球导航卫星系统无线电掩星测量中估算零星辐射强度的改进模型

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2023-12-22 DOI: 10.3389/fspas.2023.1327979

Daniel J. Emmons, Dong L. Wu, N. Swarnalingam, Ashar F. Ali, Joseph A. Ellis, Kyle E. Fitch, Kenneth S. Obenberger

{"title":"Improved models for estimating sporadic-E intensity from GNSS radio occultation measurements","authors":"Daniel J. Emmons, Dong L. Wu, N. Swarnalingam, Ashar F. Ali, Joseph A. Ellis, Kyle E. Fitch, Kenneth S. Obenberger","doi":"10.3389/fspas.2023.1327979","DOIUrl":"https://doi.org/10.3389/fspas.2023.1327979","url":null,"abstract":"Several models for estimating sporadic-E intensity from Global Navigation Satellite System (GNSS) radio occultation (RO) observation have previously been developed using a single perturbation or intensity parameter, such as phase-based total electron content (TEC) or the amplitude-based S4 index. Here, we outline two new models that use a combination of phase and amplitude parameters for the L1 and L2 signals. These models show a significant improvement over the baseline models used for comparison. Furthermore, the GNSS-RO parameters are compared with several different ionosonde intensity parameters including the direct foEs and fbEs measurements along with the metallic-ion based foμEs and fbμEs parameters which account for the background E-region density. Interestingly, the phase-based σϕ scintillation index shows the strongest correlation to foEs and fbEs while amplitude-based S4 shows the strongest correlation to foμEs and fbμEs. While the metallic-ion based foμEs and fbμEs parameters are physically ideal for GNSS-RO observations, we show difficulties in practical implementation due to the reliance on a background E-region density estimate using a model such as the International Reference Ionosphere (IRI). Ultimately, we provide two improved sporadic-E intensity models that can be used for future GNSS-RO based studies along with a recommendation to compare against the ionosonde-based foEs parameter.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"7 3","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138947338","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}

引用次数: 0

Jitter error evaluation in large-aperture optical telescopes based on normalized point source sensitivity 基于归一化点源灵敏度的大口径光学望远镜抖动误差评估

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2023-12-15 DOI: 10.3389/fspas.2023.1311323

Yuan-Guo Liu, Yang Fei, Jia-Kang Zhu, Yin-Long Huo

引用次数: 0

Observations and simulations of large-scale traveling ionospheric disturbances during the January 14-15, 2022 geomagnetic storm 2022 年 1 月 14-15 日地磁风暴期间大尺度巡回电离层扰动的观测与模拟

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2023-12-15 DOI: 10.3389/fspas.2023.1297632

Kedeng Zhang, Hui Wang

{"title":"Observations and simulations of large-scale traveling ionospheric disturbances during the January 14-15, 2022 geomagnetic storm","authors":"Kedeng Zhang, Hui Wang","doi":"10.3389/fspas.2023.1297632","DOIUrl":"https://doi.org/10.3389/fspas.2023.1297632","url":null,"abstract":"Using the total electron content (TEC) observations from GPS, and simulations from the Thermosphere Ionosphere Electrodynamic General Circulation Model (TIEGCM), this work investigates the large-scale traveling ionospheric disturbances (LSTIDs) and the possible involved drivers during the geomagnetic storm on January 14-15, 2022. Based on the term analysis of O+ continuity equation in TIEGCM, it is found that the traveling atmospheric disturbances in equatorward winds are responsible for the LSTIDs, with minor contributions from plasma drifts owing to the prompt penetration electric field. A strong interhemispheric asymmetry of the LSTIDs is observed, which might be attributed to both the equatorward wind disturbances and background plasma. The stronger wind (plasma) disturbances occurs in the winter hemisphere than that in the summer hemisphere. The maximum magnitude of LSTIDs in electron density disturbances occurs at ∼250 and ∼270 km in the northern and southern hemispheres, respectively, owing to both the thermospheric equatorward winds and background plasma. An interesting phenomenon that tail-like LSTIDs occur at the dip equator and low latitudes might be related to the eruption of the Tonga volcano, but it is not well reproduced in TIEGCM that deserves further exploration in a future study.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"287 4","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138996540","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}

引用次数: 0

Impacts of Kelvin-Helmholtz billow formation on GNSS radio occultation measurements of sporadic-E 开尔文-赫尔姆霍兹波浪形成对全球导航卫星系统零星-E 无线电掩星测量的影响

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2023-12-14 DOI: 10.3389/fspas.2023.1280228

A. Knisely, Daniel J. Emmons

{"title":"Impacts of Kelvin-Helmholtz billow formation on GNSS radio occultation measurements of sporadic-E","authors":"A. Knisely, Daniel J. Emmons","doi":"10.3389/fspas.2023.1280228","DOIUrl":"https://doi.org/10.3389/fspas.2023.1280228","url":null,"abstract":"Global Navigation Satellite System (GNSS) Radio Occultation (RO) has shown great promise for monitoring sporadic-E layers. However, extracting sporadic-E information from RO signals remains a difficult task due to the many unknown parameters such as length, intensity, vertical thickness, and small-scale structure or turbulence. To further our understanding of sporadic-E turbulence, we investigate the power spectra of sporadic-E layers during Kelvin-Helmholtz billow formation. Additionally, RO signals traversing the billows are simulated to analyze the impact on both amplitude and phase. From this, we find that the horizontal power spectrum is generally steeper in sporadic-E layers without billow formation, and the spectrum flattens as small-scale structures develop. Additionally, the typical “U”-shaped RO amplitude profiles produced by sporadic-E layers become asymmetric and less defined as the billows form and progress, showing that a single sporadic-E layer can produce a variety of RO signatures as it evolves over time. Ultimately, these results provide valuable insight for both modeling RO signals through sporadic-E layers and inverting RO data to extract information about the layers.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"1998 2","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139002213","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}

引用次数: 0

Implementation of an automated process for Limnospira indica harvesting and culture medium recycling for space applications 实施用于空间应用的褐飞虱收获和培养基回收自动化流程

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2023-12-13 DOI: 10.3389/fspas.2023.1229043

Jordan Tallec, Marie Vandermies, Céline Coene, Brigitte Lamaze-Lefebvre, Dries Demey, M. Frappart, E. Couallier

{"title":"Implementation of an automated process for Limnospira indica harvesting and culture medium recycling for space applications","authors":"Jordan Tallec, Marie Vandermies, Céline Coene, Brigitte Lamaze-Lefebvre, Dries Demey, M. Frappart, E. Couallier","doi":"10.3389/fspas.2023.1229043","DOIUrl":"https://doi.org/10.3389/fspas.2023.1229043","url":null,"abstract":"Future long-term space exploration missions require the implementation of circular life support systems for the supply of water, oxygen and food from mission wastes. Therefore, separation systems dealing with multi-phasic streams need to be addressed. The BioHarvest (BHV) study focused on solid/liquid separation in space with the aim to demonstrate the continuous separation and harvesting of the cyanobacterium Limnospira indica from its culture broth under axenic conditions. The cyanobacterium biomass is intended to be used for further food processing while the broth free of organic matter and resupplied with nutrients should be directly recycled into the photobioreactor (PBR). In this study, an automated breadboard model based on a two-step process was built. First, a Biomass Harvesting Unit (BHU) separates the biomass produced in the PBR from the culture medium with dead-end filtration. Second, the Medium Filtration Unit (MFU) further treats the culture medium to retain the dissolved organic compounds using crossflow filtration. The performances of BHU and MHU met the requirements in batch mode and in short continuous mode: the BHU was able to retain all the biomass and the MFU could retain more than 90% of organic matter while being permeable to nutrients. The productivity of the MFU was also very good, with a high permeation flux allowing treating the targeted 80 L of culture per day. However, continuous operation of the BHV technology could not be achieved in the long term due to biomass accumulation as a sticky cake with a high specific resistance on the BHU filter, despite backwashing cycles and intense vibrations. Future work shall therefore focus on this critical step, to improve process performance by preventing fouling of the filter sheets.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"118 12","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139003845","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}

引用次数: 0

Electron diffusion by chorus waves: effects of latitude-dependent wave power spectrum 合唱波的电子扩散：纬度波功率谱的影响

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2023-12-12 DOI: 10.3389/fspas.2023.1333184

Jiang Yu, Jing Wang, Zhaoguo He, Zuzheng Chen, Liuyuan Li, Jun Cui, Jinbin Cao

引用次数: 0

Insights into the first and second hydrostatic core stages from numerical simulations 数值模拟对第一和第二静压核心阶段的启示

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2023-12-05 DOI: 10.3389/fspas.2023.1288730

Alison K. Young

{"title":"Insights into the first and second hydrostatic core stages from numerical simulations","authors":"Alison K. Young","doi":"10.3389/fspas.2023.1288730","DOIUrl":"https://doi.org/10.3389/fspas.2023.1288730","url":null,"abstract":"The theory of how low mass stars form from the collapse of a dense molecular cloud core has been well-established for decades. Thanks to significant progress in computing and numerical modelling, more physical models have been developed and a wider parameter space explored to understand the early stages of star formation more fully. In this review, I describe the expected physical properties of the first and second core stages and how the inclusion of different physics affects those predicted characteristics. I provide an overview of chemical models and synthetic observations, looking towards the positive identification of the first core in nature, which remains elusive. However, there are a few likely candidate first cores, which are listed, and I briefly discuss the recent progress in characterising the youngest protostellar sources. Chemistry will be instrumental in the firm identification of the first core so we require robust theoretical predictions of the chemical evolution of protostellar cores, especially of the first and second core outflows. Looking ahead, simulations can shed light on how the protostellar collapse phase shapes the evolution of the protostellar disc. Simulations of dust evolution during protostellar core collapse show there is significant enhancement in grain size and abundance towards the centre of the core. Chemical models show that the warm, dense conditions of the first core drive chemical evolution. There is a wide scope for further study of the role that the first and second core stages play in determining the structure and composition of the protostellar disc and envelope and, of course, the eventual influence on the formation of planets.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"17 3","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138598446","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}

引用次数: 0

The temporal and latitudinal dependences of turbulence driven by pickup ions in the outer heliosphere 外日光层拾取离子驱动湍流的时间和纬度相关性

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2023-12-01 DOI: 10.3389/fspas.2023.1298577

Bingbing Wang, Lingling Zhao, Paria Abouhamzeh, G. Zank, L. Adhikari

{"title":"The temporal and latitudinal dependences of turbulence driven by pickup ions in the outer heliosphere","authors":"Bingbing Wang, Lingling Zhao, Paria Abouhamzeh, G. Zank, L. Adhikari","doi":"10.3389/fspas.2023.1298577","DOIUrl":"https://doi.org/10.3389/fspas.2023.1298577","url":null,"abstract":"The distribution of turbulence in the heliosphere remains a mystery, due to the complexity in not only modeling the turbulence transport equations but also identifying the drivers of turbulence that vary with time and spatial location. Beyond the ionization cavity (a few astronomical units (AU) from the Sun), the turbulence is driven predominantly by freshly created pickup ions (PUIs), in contrast to the driving by stream shear and compression. Understanding the source characteristics is necessary to refine turbulence transport models and interpret measurements of turbulence and solar wind temperature in the outer heliosphere. Using a recent latitude-dependent solar wind speed model and the ionization rate of neutral interstellar hydrogen (H), we investigate the temporal and spatial variation in the strength of low-frequency turbulence driven by PUIs from 1998 to 2020. We find that the driving rate is stronger during periods of high solar activity and at lower latitudes in the outer heliosphere. The driving rates for parallel and anti-parallel propagating (relative to the background magnetic field) slab turbulence have different spatial and latitude dependences. The calculated generation rate of turbulence by PUIs is an essential ingredient to investigate the latitude dependence of turbulence in the outer heliosphere, which is important to understand the heating of the distant solar wind and the modulation of cosmic rays.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":" 41","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138618365","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}

引用次数: 0

Nuclear data resources and initiatives for nuclear astrophysics 核天体物理学的核数据资源和倡议

3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2023-11-10 DOI: 10.3389/fspas.2023.1243615

Michael S. Smith

{"title":"Nuclear data resources and initiatives for nuclear astrophysics","authors":"Michael S. Smith","doi":"10.3389/fspas.2023.1243615","DOIUrl":"https://doi.org/10.3389/fspas.2023.1243615","url":null,"abstract":"Research into the cosmic synthesis of the elements, the evolution and explosion of stars, the nature of the early Universe, and other important topics in nuclear astrophysics are at the forefront of nuclear science. These studies are motivating laboratory measurements and theoretical calculations that, after significant investments, are pushing the boundaries of what is possible. The latest nuclear results, however, must be specially prepared before they can be used to advance our knowledge of the cosmos. This processing requires a set of resources unique to nuclear astrophysics, and an impressive collection of nuclear reaction and nuclear structure datasets, processing codes, thermonuclear reaction rate libraries, and simulation codes and services have been developed for the field. There are, however, some serious challenges to these efforts that will only worsen in the future, making it important to develop strategies and act now to ensure a sustainable future for this work. After detailing the specific data types needed for nuclear astrophysics and the available data resources, the major challenges in this work and their implications are discussed. A set of initiatives are proposed to meet those challenges along with suggested implementations and possible ways that they may advance our understanding of the Universe and strengthen the field of nuclear astrophysics.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":" March","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135186400","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}

引用次数: 0

Effects of the evolving early Moon and Earth magnetospheres 早期月球和地球磁层演化的影响

3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2023-11-10 DOI: 10.3389/fspas.2023.1112233

James Green, Scott Boardsen, Chuanfei Dong

{"title":"Effects of the evolving early Moon and Earth magnetospheres","authors":"James Green, Scott Boardsen, Chuanfei Dong","doi":"10.3389/fspas.2023.1112233","DOIUrl":"https://doi.org/10.3389/fspas.2023.1112233","url":null,"abstract":"Recently it has been identified that our Moon had an extensive magnetosphere for several hundred million years soon after it was formed when the Moon was within 20 Earth Radii (R E ) from the Earth. Some aspects of the interaction between the early Earth-Moon magnetospheres are investigated by mapping the interconnected field lines between the Earth and the Moon and investigating how the early lunar magnetosphere affects the magnetospheric dynamics within the coupled magnetospheres over time. So long as the magnetosphere of the Moon remains strong as it moves away from the Earth in the antialigned dipole configuration, the extent of the Earth’s open field lines decreases. As a result, at times it significantly changes the structure of the field-aligned current system, pushing the polar cusp significantly northward, and forcing magnetotail reconnection sites into the deeper tail region. In addition, the combined magnetospheres of the Earth and the Moon greatly extend the number of closed field lines enabling a much larger plasmasphere to exist and connecting the lunar polar cap with closed field lines to the Earth. That configuration supports the transfer of plasma between the Earth and the Moon potentially creating a time capsule of the evolution of volatiles with depth. This paper only touches on the evolution of the early Earth and Moon magnetospheres, which has been a largely neglected space physics problem and has great potential for complex follow-on studies using more advanced tools and due to the expected new lunar data coming in the next decade through the Artemis Program.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":" August","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135186910","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}

引用次数: 0