Frontiers in Astronomy and Space Sciences最新文献

{"title":"Multi-wavelength observations and modeling of a microflare: constraining non-thermal particle acceleration","authors":"Vanessa Polito, Marianne Peterson, Lindsay Glesener, Paola Testa, Sijie Yu, Katharine K. Reeves, Xudong Sun, Jessie Duncan","doi":"10.3389/fspas.2023.1214901","DOIUrl":"https://doi.org/10.3389/fspas.2023.1214901","url":null,"abstract":"In this work we analyze a small B-class flare that occurred on 29 April 2021 and was observed simultaneously by the Interface Region Imaging Spectrograph (IRIS) and the Nuclear Spectroscopic Telescope Array (NuSTAR) X-ray instrument. The IRIS observations of the ribbon of the flare show peculiar spectral characteristics that are typical signatures of energy deposition by non-thermal electrons in the lower atmosphere. The presence of the non-thermal particles is also confirmed directly by fitting the NuSTAR spectral observations. We show that, by combining IRIS and NuSTAR multi-wavelength observations from the corona to the lower atmosphere with hydrodynamic simulations using the RADYN code, we can provide strict constraints on electron-beam heated flare models. This work presents the first NuSTAR, IRIS and RADYN joint analysis of a non-thermal microflare, and presents a self-consistent picture of the flare-accelerated electrons in the corona and the chromospheric response to those electrons.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136129870","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":"Survey of reconnection signatures in auroral oval ion precipitation","authors":"T. Sotirelis, P. T. Newell, C. Meng","doi":"10.3389/fspas.2023.1200263","DOIUrl":"https://doi.org/10.3389/fspas.2023.1200263","url":null,"abstract":"The protons and electrons on newly reconnected field lines exhibit time-of-flight effects that have been observed and modelled on both the dayside and nightside, at both high and low altitudes. These reconnection signatures feature proton energy distributions that are cutoff toward low energy. In LEO the cutoff energy exhibits a dispersion with latitude, typically seen in the cusp on the dayside, and referred to as velocity dispersed ion structures on the nightside. Here, an automated algorithm for detecting such low-energy cutoffs in the energy spectra of precipitating ions was developed, without regard for any possible dispersion with latitude. The occurrences of LEC ion spectra were mapped over a year of DMSP observations. There are four distinct components to this map, two of which are produced by reconnection. On the dayside LEC ion spectra are seen in cusp, mantle, and open-LLBL precipitation, predominantly at sub-keV energies, as the result of dayside reconnection. On the nightside LEC ion spectra are seen at the poleward edge of the oval at supra-keV energies (usually dispersed with latitude), that indicate magnetotail reconnection. There is another supra-keV population seen on the dusk side at the equatorward edge of the oval, possibly indicating the onset of isotropy. Finally, there is a sub-keV population seen throughout the auroral oval that is thought to consist of ions accelerated out of the opposing hemisphere. The presence of the nightside reconnection signature is modulated by magnetic activity level. Superposed epoch analyses of the ionospheric flow velocity reveal flow through the open–closed boundary when reconnection signatures are present, and enhanced upflow on the dayside when reconnection signatures are present.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136263988","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":"PRIME: a probabilistic neural network approach to solar wind propagation from L1","authors":"Connor O’Brien, Brian M. Walsh, Ying Zou, Samira Tasnim, Huaming Zhang, David Gary Sibeck","doi":"10.3389/fspas.2023.1250779","DOIUrl":"https://doi.org/10.3389/fspas.2023.1250779","url":null,"abstract":"Introduction: For the last several decades, continuous monitoring of the solar wind has been carried out by spacecraft at the first Earth-Sun Lagrange point (L1). Due to computational expense or model limitations, those data often must be propagated to some point closer to the Earth in order to be usable by those studying the interaction between Earth’s magnetosphere and the solar wind. The current most widely used tool to propagate measurements from L1 (roughly 235 RE upstream) to Earth is the planar propagation method, which includes a number of known limitations. Motivated by these limitations, this study introduces a new algorithm called the Probabilistic Regressor for Input to the Magnetosphere Estimation (PRIME). Methods: PRIME is based on a novel probabilistic recurrent neural network architecture, and is capable of incorporating solar wind time history from L1 monitors to generate predictions of near-Earth solar wind as well as estimate uncertainties for those predictions. Results: A statistical validation shows PRIME’s predictions better match MMS magnetic field and plasma measurements just upstream of the bow shock than measurements from Wind propagated to MMS with a minimum variance analysis-based planar propagation technique. PRIME’s continuous rank probability score (CRPS) is 0.214 σ on average across all parameters, compared to the minimum variance algorithm’s CRPS of 0.350 σ . PRIME’s performance improvement over minimum variance is dramatic in plasma parameters, with an improvement in CRPS from 2.155 cm −3 to 0.850 cm −3 in number density and 16.15 km/s to 9.226 km/s in flow velocity V X GSE. Discussion: Case studies of particularly difficult to predict or extreme conditions are presented to illustrate the benefits and limitations of PRIME. PRIME’s uncertainties are shown to provide reasonably reliable predictions of the probability of particular solar wind conditions occurring. Conclusion: PRIME offers a simple solution to common limitations of solar wind propagation algorithms by generating accurate predictions of the solar wind at Earth with physically meaningful uncertainties attached.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135059110","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":"Ionosphere-thermosphere coupling via global-scale waves: new insights from two-years of concurrent in situ and remotely-sensed satellite observations","authors":"Federico Gasperini, Brian J. Harding, Geoffrey Crowley, Thomas J. Immel","doi":"10.3389/fspas.2023.1217737","DOIUrl":"https://doi.org/10.3389/fspas.2023.1217737","url":null,"abstract":"Growing evidence indicates that a selected group of global-scale waves from the lower atmosphere constitute a significant source of ionosphere-thermosphere (IT, 100–600 km) variability. Due to the geometry of the magnetic field lines, this IT coupling occurs mainly at low latitudes ( <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m1\"><mml:mo><</mml:mo></mml:math> 30°) and is driven by waves originating in the tropical troposphere such as the diurnal eastward propagating tide with zonal wave number s = −3 (DE3) and the quasi-3-day ultra-fast Kelvin wave with s = −1 (UFKW1). In this work, over 2 years of simultaneous in situ ion densities from Ion Velocity Meters (IVMs) onboard the Ionospheric Connection Explorer (ICON) near 590 km and the Scintillation Observations and Response of the Ionosphere to Electrodynamics (SORTIE) CubeSat near 420 km, along with remotely-sensed lower (ca. 105 km) and middle (ca. 220 km) thermospheric horizontal winds from ICON’s Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) are employed to demonstrate a rich spectrum of waves coupling these IT regions. Strong DE3 and UFKW1 topside ionospheric variations are traced to lower thermospheric zonal winds, while large diurnal s = 2 (DW2) and zonally symmetric (D0) variations are traced to middle thermospheric winds generated in situ . Analyses of diurnal tides from the Climatological Tidal Model of the Thermosphere (CTMT) reveal general agreement near 105 km, with larger discrepancies near 220 km due to in situ tidal generation not captured by CTMT. This study highlights the utility of simultaneous satellite measurements for studies of IT coupling via global-scale waves.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135206395","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":"Effect of fish density on biological production in aquaponics combining lettuce hydroponics and loach aquaculture for controlled ecological life support systems in space","authors":"Yoshiaki Kitaya, Takashige Kawamoto, Ryosuke Endo, Toshio Shibuya","doi":"10.3389/fspas.2023.1197402","DOIUrl":"https://doi.org/10.3389/fspas.2023.1197402","url":null,"abstract":"There is a need to develop production technology that effectively uses limited water and other resources to create a stable food supply in space. Aquaponics, which combine hydroponics and aquaculture, is expected to be an efficient system for producing crops and animal proteins. This system sustains the reuse of water and balances nutrient elements between both cultures using dissolved elements in fish excrement for plant growth. To evaluate the effect of fish density on biological production and nitrogen usage efficiency in aquaponics combining lettuce hydroponics and loach aquaculture, we investigated the growth performance of lettuce plants and loach fish. We focused on the balance of nutrient elements, especially nitrogen flow in the system. As a result, we found that lettuce grew in aquaponics with a half-strength standard solution with an optimal combination of the number of plants and fish as well as hydroponics with a standard solution. Increasing the density of loach fish and lettuce plants can increase the total biological production of fish and plants. However, it will be important to control both fish and plant densities to increase nitrogen recovery in aquaponics with a high fish density.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"174 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135207014","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":"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}

{"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}

{"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}

{"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}

{"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}