The Sun is a standard reference object for Astrophysics and also a fascinating subject of study in its own right. X-ray and extreme ultraviolet movies of the Sun's atmosphere show an extraordinary diversity of plasma phenomena, from barely visible bursts and jets to coronal mass ejections that impact a large portion of the solar surface. The processes that produce these phenomena, heat the corona and power the solar wind remain actively studied and accurate atomic data are essential for interpreting observations and making model predictions. For the Sun's interior intense effort is focused on resolving the "solar problem," (a discrepancy between solar interior models and helioseismology measurements) and atomic data are central to both element abundance measurements and interior physics such as opacity and nuclear reaction rates. In this article, topics within solar interior and solar atmosphere physics are discussed and the role of atomic data described. Areas of active research are highlighted and specific atomic data needs are identified.
太阳是天体物理学的标准参照物，其本身也是一个引人入胜的研究课题。太阳大气层的 X 射线和极紫外视频显示了非凡多样的等离子体现象，从几乎看不见的爆发和喷射到影响大部分太阳表面的日冕物质抛射。对产生这些现象、加热日冕和为太阳风提供动力的过程仍在进行积极的研究，准确的原子数据对于解释观测结果和进行模型预测至关重要。对于太阳内部，人们正集中精力解决 "太阳问题"（太阳内部模型与日光地震学测量之间的差异），而原子数据对于元素丰度测量和内部物理学（如不透明度和核反应速率）都至关重要。本文讨论了太阳内部物理学和太阳大气物理学的主题，并介绍了原子数据的作用。文章强调了正在进行的研究领域，并指出了具体的原子数据需求。
{"title":"Applications of Atomic Data to Studies of the Sun","authors":"Peter R. Young","doi":"arxiv-2409.09166","DOIUrl":"https://doi.org/arxiv-2409.09166","url":null,"abstract":"The Sun is a standard reference object for Astrophysics and also a\u0000fascinating subject of study in its own right. X-ray and extreme ultraviolet\u0000movies of the Sun's atmosphere show an extraordinary diversity of plasma\u0000phenomena, from barely visible bursts and jets to coronal mass ejections that\u0000impact a large portion of the solar surface. The processes that produce these\u0000phenomena, heat the corona and power the solar wind remain actively studied and\u0000accurate atomic data are essential for interpreting observations and making\u0000model predictions. For the Sun's interior intense effort is focused on\u0000resolving the \"solar problem,\" (a discrepancy between solar interior models and\u0000helioseismology measurements) and atomic data are central to both element\u0000abundance measurements and interior physics such as opacity and nuclear\u0000reaction rates. In this article, topics within solar interior and solar\u0000atmosphere physics are discussed and the role of atomic data described. Areas\u0000of active research are highlighted and specific atomic data needs are\u0000identified.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Scintillations of radio frequency signals due to the ionosphere, despite having been studied for decades, is still an active area of research. Of particular interest is the scintillations near the geomagnetic equator, where such scintillations can be strong enough to cause disruptions to satellite communications. In this paper, a low cost system to monitor VHF scintillations is described. The system called the Personal Ionospheric Experiment (PIE) makes use of a widely available software defined radio (SDR) to perform the measurements. The use of an SDR vastly enhances the flexibility, especially in environments with non-negligible radio frequency interference (RFI). A simple technique to effectively subtract out transient RFI commonly found in radio data is detailed, and tested with data collected over several months. The utility of the proposed system is demonstrated with the analysis of a night-time scintillation patch; a few daytime scintillations are also reported. Therefore this paper demonstrates the feasibility of conducting useful low-cost radio science experiments in semi-urban locations with RFI, encouraging similar citizen science initiatives.
{"title":"First results from a low cost software defined radio system monitoring VHF equatorial ionospheric scintillations in the Indian sector","authors":"Jishnu N. Thekkeppattu","doi":"arxiv-2409.07758","DOIUrl":"https://doi.org/arxiv-2409.07758","url":null,"abstract":"Scintillations of radio frequency signals due to the ionosphere, despite\u0000having been studied for decades, is still an active area of research. Of\u0000particular interest is the scintillations near the geomagnetic equator, where\u0000such scintillations can be strong enough to cause disruptions to satellite\u0000communications. In this paper, a low cost system to monitor VHF scintillations\u0000is described. The system called the Personal Ionospheric Experiment (PIE) makes\u0000use of a widely available software defined radio (SDR) to perform the\u0000measurements. The use of an SDR vastly enhances the flexibility, especially in\u0000environments with non-negligible radio frequency interference (RFI). A simple\u0000technique to effectively subtract out transient RFI commonly found in radio\u0000data is detailed, and tested with data collected over several months. The\u0000utility of the proposed system is demonstrated with the analysis of a\u0000night-time scintillation patch; a few daytime scintillations are also reported.\u0000Therefore this paper demonstrates the feasibility of conducting useful low-cost\u0000radio science experiments in semi-urban locations with RFI, encouraging similar\u0000citizen science initiatives.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142178382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rajkumar Hajra, Bruce Tsatnam Tsurutani, Quanming Lu, Richard B. Horne, Gurbax Singh Lakhina, Xu Yang, Pierre Henri, Aimin Du, Xingliang Gao, Rongsheng Wang, San Lu
The 23-24 April 2023 double-peak (SYM-H intensities of -179 and -233 nT) intense geomagnetic storm was caused by interplanetary magnetic field southward component Bs associated with an interplanetary fast-forward shock-preceded sheath (Bs of 25 nT), followed by a magnetic cloud (MC) (Bs of 33 nT), respectively. At the center of the MC, the plasma density exhibited an order of magnitude decrease, leading to a sub-Alfvenic solar wind interval for ~2.1 hr. Ionospheric Joule heating accounted for a significant part (~81%) of the magnetospheric energy dissipation during the storm main phase. Equal amount of Joule heating in the dayside and nightside ionosphere is consistent with the observed intense and global-scale DP2 (disturbance polar) currents during the storm main phase. The sub-Alfvenic solar wind is associated with disappearance of substorms, a sharp decrease in Joule heating dissipation, and reduction in electromagnetic ion cyclotron wave amplitude. The shock/sheath compression of the magnetosphere led to relativistic electron flux losses in the outer radiation belt between L* = 3.5 and 5.5. Relativistic electron flux enhancements were detected in the lower L* < 3.5 region during the storm main and recovery phases. Equatorial ionospheric plasma anomaly structures are found to be modulated by the prompt penetration electric fields. Around the anomaly crests, plasma density at ~470 km altitude and altitude-integrated ionospheric total electron content are found to increase by ~60% and ~80%, with ~33% and ~67% increases in their latitudinal extents compared to their quiet-time values, respectively.
{"title":"The April 2023 SYM-H = -233 nT Geomagnetic Storm: A Classical Event","authors":"Rajkumar Hajra, Bruce Tsatnam Tsurutani, Quanming Lu, Richard B. Horne, Gurbax Singh Lakhina, Xu Yang, Pierre Henri, Aimin Du, Xingliang Gao, Rongsheng Wang, San Lu","doi":"arxiv-2409.08118","DOIUrl":"https://doi.org/arxiv-2409.08118","url":null,"abstract":"The 23-24 April 2023 double-peak (SYM-H intensities of -179 and -233 nT)\u0000intense geomagnetic storm was caused by interplanetary magnetic field southward\u0000component Bs associated with an interplanetary fast-forward shock-preceded\u0000sheath (Bs of 25 nT), followed by a magnetic cloud (MC) (Bs of 33 nT),\u0000respectively. At the center of the MC, the plasma density exhibited an order of\u0000magnitude decrease, leading to a sub-Alfvenic solar wind interval for ~2.1 hr.\u0000Ionospheric Joule heating accounted for a significant part (~81%) of the\u0000magnetospheric energy dissipation during the storm main phase. Equal amount of\u0000Joule heating in the dayside and nightside ionosphere is consistent with the\u0000observed intense and global-scale DP2 (disturbance polar) currents during the\u0000storm main phase. The sub-Alfvenic solar wind is associated with disappearance\u0000of substorms, a sharp decrease in Joule heating dissipation, and reduction in\u0000electromagnetic ion cyclotron wave amplitude. The shock/sheath compression of\u0000the magnetosphere led to relativistic electron flux losses in the outer\u0000radiation belt between L* = 3.5 and 5.5. Relativistic electron flux\u0000enhancements were detected in the lower L* < 3.5 region during the storm main\u0000and recovery phases. Equatorial ionospheric plasma anomaly structures are found\u0000to be modulated by the prompt penetration electric fields. Around the anomaly\u0000crests, plasma density at ~470 km altitude and altitude-integrated ionospheric\u0000total electron content are found to increase by ~60% and ~80%, with ~33% and\u0000~67% increases in their latitudinal extents compared to their quiet-time\u0000values, respectively.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142178383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Parker Solar Probe (PSP) spacecraft has transited the inner-most regions of the zodiacal cloud and detects impacts to the spacecraft body via its electric field instrument. Multiple dust populations have been proposed to explain the PSP dust impact rates. PSP's unique orbit allows us to identify a region where the impact rates are likely dominated by $alpha$-meteoroids, small zodiacal grains on approximately circular, bound orbits. From the distribution of voltage signals generated by dust impacts to PSP in this region, we find the cumulative mass index for grains with radii of $sim$0.6-1.4 $mu$m (masses of $3times10^{-15}$ to $3times10^{-14}$ kg) to be $alpha = 1.1 pm 0.3$ from 0.1-0.25 $R_odot$. $alpha$ increases toward the Sun, with even smaller fragments generated closer to the Sun. The derived size distribution is steeper than previously estimated, and in contrast to expectations we find most of the dust mass resides in the smallest fragments and not in large grains inside 0.15 au. As the inner-most regions of the zodiacal cloud are likely collisionally evolved, these results place new constraints how the solar system's zodiacal cloud and by extension astrophysical debris disks are partitioned in mass.
{"title":"Size distribution of small grains in the inner zodiacal cloud","authors":"J. R. Szalay, P. Pokorný, D. M. Malaspina","doi":"arxiv-2409.07411","DOIUrl":"https://doi.org/arxiv-2409.07411","url":null,"abstract":"The Parker Solar Probe (PSP) spacecraft has transited the inner-most regions\u0000of the zodiacal cloud and detects impacts to the spacecraft body via its\u0000electric field instrument. Multiple dust populations have been proposed to\u0000explain the PSP dust impact rates. PSP's unique orbit allows us to identify a\u0000region where the impact rates are likely dominated by $alpha$-meteoroids,\u0000small zodiacal grains on approximately circular, bound orbits. From the\u0000distribution of voltage signals generated by dust impacts to PSP in this\u0000region, we find the cumulative mass index for grains with radii of\u0000$sim$0.6-1.4 $mu$m (masses of $3times10^{-15}$ to $3times10^{-14}$ kg) to\u0000be $alpha = 1.1 pm 0.3$ from 0.1-0.25 $R_odot$. $alpha$ increases toward\u0000the Sun, with even smaller fragments generated closer to the Sun. The derived\u0000size distribution is steeper than previously estimated, and in contrast to\u0000expectations we find most of the dust mass resides in the smallest fragments\u0000and not in large grains inside 0.15 au. As the inner-most regions of the\u0000zodiacal cloud are likely collisionally evolved, these results place new\u0000constraints how the solar system's zodiacal cloud and by extension\u0000astrophysical debris disks are partitioned in mass.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142178388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The relationship between a moderate level of geomagnetic activity, represented by the Kp index (2- - 5+), and solar wind conditions were revealed based on Potential Learning (PL), and dependence of particular solar wind plasma density (NP) on moderate geomagnetic conditions was discussed. It has poorly been understood from what stage of geomagnetic activity NP begins to control the Kp level. Previously, PL succeeded to extract the most influential solar wind parameters at an extremely low (0 - 1+) and high (6- - 9) Kp ranges under southward interplanetary magnetic field (IMF) conditions. The IMF three components, solar wind flow speed (VX), and NP obtained from the 21-year OMNI solar wind database were used as the PL input parameters. PL extracted VX as the most significant parameter for the moderate Kp level under southward IMF conditions and NP is the second most influential parameter. Based on the examination of the statistical relationship between VX and NP under extremely low, high, and moderate Kp levels using the PL database, geomagnetic conditions remain high while NP becomes large, even if VX decreases (or remains similar). This shows that both VX and NP govern geomagnetic activity, following the relational equation between Kp and the solar wind plasma parameter. Based on the relation between VX and NP clarified by PL and incidental statistical studies using PL input data, we also revealed that NP begins to affect the Kp level from moderate geomagnetic activity level. These results suggest that even under southward IMF conditions, the geomagnetic activity might be influenced by fast (slow) VX and low (high) NP. Our results would greatly help understand general relationship between solar wind conditions and geomagnetic activity under various IMF conditions, and forecast the geomagnetic activity under extreme solar wind conditions.
{"title":"Dependence of the Solar Wind Plasma Density on Moderate Geomagnetic Activity Elucidated by Potential Learning","authors":"Ryozo Kitajima, Motoharu Nowada, Ryotaro Kamimura","doi":"arxiv-2409.07073","DOIUrl":"https://doi.org/arxiv-2409.07073","url":null,"abstract":"The relationship between a moderate level of geomagnetic activity,\u0000represented by the Kp index (2- - 5+), and solar wind conditions were revealed\u0000based on Potential Learning (PL), and dependence of particular solar wind\u0000plasma density (NP) on moderate geomagnetic conditions was discussed. It has\u0000poorly been understood from what stage of geomagnetic activity NP begins to\u0000control the Kp level. Previously, PL succeeded to extract the most influential\u0000solar wind parameters at an extremely low (0 - 1+) and high (6- - 9) Kp ranges\u0000under southward interplanetary magnetic field (IMF) conditions. The IMF three\u0000components, solar wind flow speed (VX), and NP obtained from the 21-year OMNI\u0000solar wind database were used as the PL input parameters. PL extracted VX as\u0000the most significant parameter for the moderate Kp level under southward IMF\u0000conditions and NP is the second most influential parameter. Based on the\u0000examination of the statistical relationship between VX and NP under extremely\u0000low, high, and moderate Kp levels using the PL database, geomagnetic conditions\u0000remain high while NP becomes large, even if VX decreases (or remains similar).\u0000This shows that both VX and NP govern geomagnetic activity, following the\u0000relational equation between Kp and the solar wind plasma parameter. Based on\u0000the relation between VX and NP clarified by PL and incidental statistical\u0000studies using PL input data, we also revealed that NP begins to affect the Kp\u0000level from moderate geomagnetic activity level. These results suggest that even\u0000under southward IMF conditions, the geomagnetic activity might be influenced by\u0000fast (slow) VX and low (high) NP. Our results would greatly help understand\u0000general relationship between solar wind conditions and geomagnetic activity\u0000under various IMF conditions, and forecast the geomagnetic activity under\u0000extreme solar wind conditions.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We argue that two prominent theories of ion heating in low-$beta$ collisionless plasmas -- stochastic and quasi-linear heating -- represent similar physical processes in turbulence with different normalized cross helicities. To capture both, we propose a simple phenomenology based on the power in scales at which critically balanced fluctuations reach their smallest parallel scale. Simulations of test ions interacting with turbulence confirm our scalings across a wide range of different ion and turbulence properties, including with a steep ion-kinetic transition range as relevant to the solar wind.
{"title":"A Unified Phenomenology of Ion Heating in Low-$β$ Plasmas: Test-Particle Simulations","authors":"Zade Johnston, Jonathan Squire, Romain Meyrand","doi":"arxiv-2409.07015","DOIUrl":"https://doi.org/arxiv-2409.07015","url":null,"abstract":"We argue that two prominent theories of ion heating in low-$beta$\u0000collisionless plasmas -- stochastic and quasi-linear heating -- represent\u0000similar physical processes in turbulence with different normalized cross\u0000helicities. To capture both, we propose a simple phenomenology based on the\u0000power in scales at which critically balanced fluctuations reach their smallest\u0000parallel scale. Simulations of test ions interacting with turbulence confirm\u0000our scalings across a wide range of different ion and turbulence properties,\u0000including with a steep ion-kinetic transition range as relevant to the solar\u0000wind.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142178384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Motoharu Nowada, Yukinaga Miyashita, Aoi Nakamizo, Noora Partamies, Quan-Qi Shi
Local vortex-structured auroral spiral and a large-scale transpolar arc (TPA) were contemporaneously observed by the Polar ultraviolet imager (UVI), when a substorm almost recovered. The TPA grew along the dawnside auroral oval from the nightside to the dayside (oval-aligned TPA), and a chain of multiple auroral spots and spiral were located azimuthally near the poleward edge of the nightside auroral oval. Contemporaneous appearances of the TPA and the auroral spiral can be seen after the spiral appeared alone. Polar also detected the oval-aligned TPA and another dawnside TPA with the nightside end distorted toward the premidnight sector (J-shaped TPA) before and after the spiral's formation, respectively. To examine these associated magnetotail structures, we performed global magnetohydrodynamic (MHD) simulations, based on two different types of code, BAT-S-RUS and improved REPPU, and examined how the field-aligned current (FAC) profiles varied in association with changes of the auroral form to TPA and/or auroral spiral. Global MHD simulations with the two different types of code can reproduce the TPAs and the associated FAC structures in the magnetotail. The auroral spiral and its nightside FAC profile, however, were not formed in both simulations, suggesting that its formation process cannot be treated within an MHD framework but is closely related to some kinetic process. When the J-shaped TPA and the auroral spiral contemporaneously appeared, the two MHD simulations could not reproduce the TPA, spiral and their associated magnetotail FAC structures, also advocating that a kinetic effect related to the spiral formation might prevent the TPA occurrence.
{"title":"Contemporaneous Appearances of Local-Scale Auroral Spiral and Global-Scale Transpolar Arc: Changes of Auroras and Field-Aligned Current Profiles Before a Substorm and After Its Recovery Phase","authors":"Motoharu Nowada, Yukinaga Miyashita, Aoi Nakamizo, Noora Partamies, Quan-Qi Shi","doi":"arxiv-2409.06389","DOIUrl":"https://doi.org/arxiv-2409.06389","url":null,"abstract":"Local vortex-structured auroral spiral and a large-scale transpolar arc (TPA)\u0000were contemporaneously observed by the Polar ultraviolet imager (UVI), when a\u0000substorm almost recovered. The TPA grew along the dawnside auroral oval from\u0000the nightside to the dayside (oval-aligned TPA), and a chain of multiple\u0000auroral spots and spiral were located azimuthally near the poleward edge of the\u0000nightside auroral oval. Contemporaneous appearances of the TPA and the auroral\u0000spiral can be seen after the spiral appeared alone. Polar also detected the\u0000oval-aligned TPA and another dawnside TPA with the nightside end distorted\u0000toward the premidnight sector (J-shaped TPA) before and after the spiral's\u0000formation, respectively. To examine these associated magnetotail structures, we\u0000performed global magnetohydrodynamic (MHD) simulations, based on two different\u0000types of code, BAT-S-RUS and improved REPPU, and examined how the field-aligned\u0000current (FAC) profiles varied in association with changes of the auroral form\u0000to TPA and/or auroral spiral. Global MHD simulations with the two different\u0000types of code can reproduce the TPAs and the associated FAC structures in the\u0000magnetotail. The auroral spiral and its nightside FAC profile, however, were\u0000not formed in both simulations, suggesting that its formation process cannot be\u0000treated within an MHD framework but is closely related to some kinetic process.\u0000When the J-shaped TPA and the auroral spiral contemporaneously appeared, the\u0000two MHD simulations could not reproduce the TPA, spiral and their associated\u0000magnetotail FAC structures, also advocating that a kinetic effect related to\u0000the spiral formation might prevent the TPA occurrence.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142178386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Waste heat production represents an inevitable consequence of energy conversion as per the laws of thermodynamics. Based on this fact, by using simple theoretical models, we analyze constraints on the habitability of Earth-like terrestrial planets hosting putative technological species and technospheres characterized by persistent exponential growth of energy consumption and waste heat generation: in particular, we quantify the deleterious effects of rising surface temperature on biospheric processes and the eventual loss of liquid water. Irrespective of whether these sources of energy are ultimately stellar or planetary (e.g., nuclear, fossil fuels) in nature, we demonstrate that the loss of habitable conditions on such terrestrial planets may be expected to occur on timescales of $lesssim 1000$ years, as measured from the start of the exponential phase, provided that the annual growth rate of energy consumption is of order $1%$. We conclude by discussing the types of evolutionary trajectories that might be feasible for industrialized technological species, and sketch the ensuing implications for technosignature searches.
{"title":"Waste Heat and Habitability: Constraints from Technological Energy Consumption","authors":"Amedeo Balbi, Manasvi Lingam","doi":"arxiv-2409.06737","DOIUrl":"https://doi.org/arxiv-2409.06737","url":null,"abstract":"Waste heat production represents an inevitable consequence of energy\u0000conversion as per the laws of thermodynamics. Based on this fact, by using\u0000simple theoretical models, we analyze constraints on the habitability of\u0000Earth-like terrestrial planets hosting putative technological species and\u0000technospheres characterized by persistent exponential growth of energy\u0000consumption and waste heat generation: in particular, we quantify the\u0000deleterious effects of rising surface temperature on biospheric processes and\u0000the eventual loss of liquid water. Irrespective of whether these sources of\u0000energy are ultimately stellar or planetary (e.g., nuclear, fossil fuels) in\u0000nature, we demonstrate that the loss of habitable conditions on such\u0000terrestrial planets may be expected to occur on timescales of $lesssim 1000$\u0000years, as measured from the start of the exponential phase, provided that the\u0000annual growth rate of energy consumption is of order $1%$. We conclude by\u0000discussing the types of evolutionary trajectories that might be feasible for\u0000industrialized technological species, and sketch the ensuing implications for\u0000technosignature searches.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142178385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The magnetopause is the key region in space for the transfer of solar wind mass, momentum, and energy into the magnetosphere. During the last decade, our understanding of the structure and dynamics of Earth's magnetopause and its boundary layers has advanced considerably; thanks largely to the advent of multi-spacecraft missions such as Cluster and THEMIS. Moreover, various types of physics-based techniques have been developed for visualizing two- or three-dimensional plasma and field structures from data taken by one or more spacecraft, providing a new approach to the analysis of the spatiotemporal properties of magnetopause processes, such as magnetic reconnection and the Kelvin-Helmholtz instability (KHI). Information on the size, shape, orientation, and evolution of magnetic flux ropes or flow vortices generated by those processes can be extracted from in situ measurements. Observations show that magnetopause reconnection can be globally continuous for both southward and northward interplanetary magnetic field (IMF) conditions, but even under such circumstances, more than one X-line may exist within a certain (low-latitude or high-latitude) portion on the magnetopause and some X-lines may retreat anti-sunward. The potential global effects of such behavior are discussed. An overview is also given of the identification, excitation, evolution, and possible consequences of the magnetopause KHI: there is evidence for nonlinear KHI growth and associated vortex-induced reconnection under northward IMF. Observation-based estimates indicate that reconnection tailward of both polar cusps can be the dominant mechanism for solar wind plasma entry into the dayside magnetosphere under northward IMF. However, the mechanism by which the transferred plasma is transported into the central portion of the magnetotail, and the role of magnetopause processes in this transport remain unclear.
磁层顶是太阳风质量、动量和能量向磁层转移的关键空间区域。在过去的十年中，我们对地球磁层顶及其边界层的结构和动力学的了解有了长足的进步；这主要归功于多航天器任务的出现，如 Cluster 和 THEMIS。此外，还开发了各种类型的基于物理学的技术，用于从一个或多个航天器获取的数据中可视化二维或三维等离子体和磁场结构，为分析磁层顶过程的时空特性（如磁重连接和开尔文-赫尔姆霍兹不稳定性（KHI））提供了一种新方法。有关这些过程产生的磁通量绳或流涡的大小、形状、方向和演变的信息可以从现场测量中提取。观测结果表明，在行星际磁场（IMF）向南和向北的条件下，磁极再连接可以是全球连续的，但即使在这种情况下，在磁极上的某个（低纬度或高纬度）部分也可能存在不止一条X线，而且一些X线可能会反向向太阳退缩。讨论了这种行为的潜在全球影响。此外，还概述了磁层顶 KHI 的识别、激发、演变和可能的后果：有证据表明 KHI 非线性增长和与之相关的涡旋诱导的 IMF 向北下方的再连接。基于观测的估计表明，在 IMF 向北的情况下，两极尖顶的再连接尾流可能是太阳风等离子体进入日侧磁层的主要机制。然而，转移的等离子体被输送到磁尾中央部分的机制以及磁极过程在这一输送中的作用仍不清楚。
{"title":"Structure and dynamics of the magnetopause and its boundary layers","authors":"Hiroshi Hasegawa","doi":"arxiv-2409.05262","DOIUrl":"https://doi.org/arxiv-2409.05262","url":null,"abstract":"The magnetopause is the key region in space for the transfer of solar wind\u0000mass, momentum, and energy into the magnetosphere. During the last decade, our\u0000understanding of the structure and dynamics of Earth's magnetopause and its\u0000boundary layers has advanced considerably; thanks largely to the advent of\u0000multi-spacecraft missions such as Cluster and THEMIS. Moreover, various types\u0000of physics-based techniques have been developed for visualizing two- or\u0000three-dimensional plasma and field structures from data taken by one or more\u0000spacecraft, providing a new approach to the analysis of the spatiotemporal\u0000properties of magnetopause processes, such as magnetic reconnection and the\u0000Kelvin-Helmholtz instability (KHI). Information on the size, shape,\u0000orientation, and evolution of magnetic flux ropes or flow vortices generated by\u0000those processes can be extracted from in situ measurements. Observations show\u0000that magnetopause reconnection can be globally continuous for both southward\u0000and northward interplanetary magnetic field (IMF) conditions, but even under\u0000such circumstances, more than one X-line may exist within a certain\u0000(low-latitude or high-latitude) portion on the magnetopause and some X-lines\u0000may retreat anti-sunward. The potential global effects of such behavior are\u0000discussed. An overview is also given of the identification, excitation,\u0000evolution, and possible consequences of the magnetopause KHI: there is evidence\u0000for nonlinear KHI growth and associated vortex-induced reconnection under\u0000northward IMF. Observation-based estimates indicate that reconnection tailward\u0000of both polar cusps can be the dominant mechanism for solar wind plasma entry\u0000into the dayside magnetosphere under northward IMF. However, the mechanism by\u0000which the transferred plasma is transported into the central portion of the\u0000magnetotail, and the role of magnetopause processes in this transport remain\u0000unclear.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142178387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yangyang Shen, Olga P. Verkhoglyadova, Anton Artemyev, Michael D. Hartinger, Vassilis Angelopoulos, Xueling Shi, Ying Zou
The weakly ionized plasma in the Earth's ionosphere is controlled by a complex interplay between solar and magnetospheric inputs from above, atmospheric processes from below, and plasma electrodynamics from within. This interaction results in ionosphere structuring and variability that pose major challenges for accurate ionosphere prediction for global navigation satellite system (GNSS) related applications and space weather research. The ionospheric structuring and variability are often probed using the total electron content (TEC) and its relative perturbations (dTEC). Among dTEC variations observed at high latitudes, a unique modulation pattern has been linked to magnetospheric ultra low frequency (ULF) waves, yet its underlying mechanisms remain unclear. Here using magnetically-conjugate observations from the THEMIS spacecraft and a ground-based GPS receiver at Fairbanks, Alaska, we provide direct evidence that these dTEC modulations are driven by magnetospheric electron precipitation induced by ULF-modulated whistler-mode waves. We observed peak-to-peak dTEC amplitudes reaching ~0.5 TECU (1 TECU is equal to 10$^6$ electrons/m$^2$) with modulations spanning scales of ~5--100 km. The cross-correlation between our modeled and observed dTEC reached ~0.8 during the conjugacy period but decreased outside of it. The spectra of whistler-mode waves and dTEC also matched closely at ULF frequencies during the conjugacy period but diverged outside of it. Our findings elucidate the high-latitude dTEC generation from magnetospheric wave-induced precipitation, addressing a significant gap in current physics-based dTEC modeling. Theses results thus improve ionospheric dTEC prediction and enhance our understanding of magnetosphere-ionosphere coupling via ULF waves.
{"title":"Magnetospheric control of ionospheric TEC perturbations via whistler-mode and ULF waves","authors":"Yangyang Shen, Olga P. Verkhoglyadova, Anton Artemyev, Michael D. Hartinger, Vassilis Angelopoulos, Xueling Shi, Ying Zou","doi":"arxiv-2409.05168","DOIUrl":"https://doi.org/arxiv-2409.05168","url":null,"abstract":"The weakly ionized plasma in the Earth's ionosphere is controlled by a\u0000complex interplay between solar and magnetospheric inputs from above,\u0000atmospheric processes from below, and plasma electrodynamics from within. This\u0000interaction results in ionosphere structuring and variability that pose major\u0000challenges for accurate ionosphere prediction for global navigation satellite\u0000system (GNSS) related applications and space weather research. The ionospheric\u0000structuring and variability are often probed using the total electron content\u0000(TEC) and its relative perturbations (dTEC). Among dTEC variations observed at\u0000high latitudes, a unique modulation pattern has been linked to magnetospheric\u0000ultra low frequency (ULF) waves, yet its underlying mechanisms remain unclear.\u0000Here using magnetically-conjugate observations from the THEMIS spacecraft and a\u0000ground-based GPS receiver at Fairbanks, Alaska, we provide direct evidence that\u0000these dTEC modulations are driven by magnetospheric electron precipitation\u0000induced by ULF-modulated whistler-mode waves. We observed peak-to-peak dTEC\u0000amplitudes reaching ~0.5 TECU (1 TECU is equal to 10$^6$ electrons/m$^2$) with\u0000modulations spanning scales of ~5--100 km. The cross-correlation between our\u0000modeled and observed dTEC reached ~0.8 during the conjugacy period but\u0000decreased outside of it. The spectra of whistler-mode waves and dTEC also\u0000matched closely at ULF frequencies during the conjugacy period but diverged\u0000outside of it. Our findings elucidate the high-latitude dTEC generation from\u0000magnetospheric wave-induced precipitation, addressing a significant gap in\u0000current physics-based dTEC modeling. Theses results thus improve ionospheric\u0000dTEC prediction and enhance our understanding of magnetosphere-ionosphere\u0000coupling via ULF waves.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142178402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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