arXiv - PHYS - Space Physics最新文献_第10页

Evolution of reconnection flux during eruption of magnetic flux ropes 磁通量绳爆发期间再连接磁通量的演变

arXiv - PHYS - Space Physics Pub Date : 2024-07-25 DOI: arxiv-2407.18188

Samriddhi Sankar Maity, Piyali Chatterjee, Ranadeep Sarkar, Ijas S. Mytheen

{"title":"Evolution of reconnection flux during eruption of magnetic flux ropes","authors":"Samriddhi Sankar Maity, Piyali Chatterjee, Ranadeep Sarkar, Ijas S. Mytheen","doi":"arxiv-2407.18188","DOIUrl":"https://doi.org/arxiv-2407.18188","url":null,"abstract":"Coronal mass ejections (CMEs) are powerful drivers of space weather, with\u0000magnetic flux ropes (MFRs) widely regarded as their primary precursors.\u0000However, the variation in reconnection flux during the evolution of MFR during\u0000CME eruptions remains poorly understood. In this paper, we develop a realistic\u00003D magneto-hydrodynamic model using which we explore the temporal evolution of\u0000reconnection flux during the MFR evolution using both numerical simulations and\u0000observational data. Our initial coronal configuration features an isothermal\u0000atmosphere and a potential arcade magnetic field beneath which an MFR emerges\u0000at the lower boundary. As the MFR rises, we observe significant stretching and\u0000compression of the overlying magnetic field beneath it. Magnetic reconnection\u0000begins with the gradual formation of a current sheet, eventually culminating\u0000with the impulsive expulsion of the flux rope. We analyze the temporal\u0000evolution of reconnection fluxes during two successive MFR eruptions while\u0000continuously emerging the twisted flux rope through the lower boundary. We also\u0000conduct a similar analysis using observational data from the Helioseismic and\u0000Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA) for an\u0000eruptive event. Comparing our MHD simulation with observational data, we find\u0000that reconnection flux play a crucial role in determination of CME speeds. From\u0000the onset to the eruption, the reconnection flux shows a strong linear\u0000correlation with the velocity. This nearly realistic simulation of a solar\u0000eruption provides important insights into the complex dynamics of CME\u0000initiation and progression.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782555","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}

引用次数: 0

The operationally ready full three-dimensional magnetohydrodynamic (3D MHD) model from the Sun to Earth: COCONUT+Icarus 可运行的从太阳到地球的全三维磁流体动力学（3D MHD）模型：COCONUT+Icarus

arXiv - PHYS - Space Physics Pub Date : 2024-07-25 DOI: arxiv-2407.17903

Tinatin Baratashvili, Michaela Brchnelova, Luis Linan, Andrea Lani, Stefaan Poedts

{"title":"The operationally ready full three-dimensional magnetohydrodynamic (3D MHD) model from the Sun to Earth: COCONUT+Icarus","authors":"Tinatin Baratashvili, Michaela Brchnelova, Luis Linan, Andrea Lani, Stefaan Poedts","doi":"arxiv-2407.17903","DOIUrl":"https://doi.org/arxiv-2407.17903","url":null,"abstract":"Solar wind modelling has become a crucial area of study due to the increased\u0000dependence of modern society on technology, navigation, and power systems.\u0000Accurate space weather forecasts can predict upcoming threats to Earth's\u0000geospace. In this study, we examine a novel full magnetohydrodynamic (MHD)\u0000chain from the Sun to Earth. The goal of this study is to demonstrate the\u0000capabilities of the full MHD modelling chain from the Sun to Earth by\u0000finalising the implementation of the full MHD coronal model into the COolfluid\u0000COroNa UnsTructured (COCONUT) model and coupling it to the MHD heliospheric\u0000model Icarus. The resulting coronal model has significant advantages compared\u0000to the pre-existing polytropic alternative, as it models a more realistic\u0000bi-modal wind, which is crucial for heliospheric studies. In this study, only thermal conduction, radiative losses, and approximated\u0000coronal heating function were considered in the energy equation. A realistic\u0000specific heat ratio was applied. The output of the coronal model was used to\u0000onset the 3D MHD heliospheric model Icarus. A minimum solar activity case was\u0000chosen as the first test case for the full MHD model. The numerically simulated\u0000data in the corona and the heliosphere were compared to observational products.\u0000We present a first attempt to obtain the full MHD chain from the Sun to Earth\u0000with COCONUT and Icarus. The coronal model has been upgraded to a full MHD\u0000model for a realistic bi-modal solar wind configuration. The approximated\u0000heating functions have modelled the wind reasonably well, but simple\u0000approximations are not enough to obtain a realistic density-speed balance or\u0000realistic features in the low corona and farther, near the outer boundary. The\u0000full MHD model was computed in 1.06 h on 180 cores of the Genius cluster of the\u0000Vlaams Supercomputing Center, which is only 1.8 times longer than the\u0000polytropic simulation.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782556","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}

引用次数: 0

Revisiting Empirical Solar Energetic Particle Scaling Relations II. Coronal Mass Ejections 重新审视经验太阳能量粒子比例关系 II.日冕物质抛射

arXiv - PHYS - Space Physics Pub Date : 2024-07-23 DOI: arxiv-2407.16479

Athanasios Papaioannou, Konstantin Herbst, Tobias Ramm, David Lario, Astrid M. Veronig

{"title":"Revisiting Empirical Solar Energetic Particle Scaling Relations II. Coronal Mass Ejections","authors":"Athanasios Papaioannou, Konstantin Herbst, Tobias Ramm, David Lario, Astrid M. Veronig","doi":"arxiv-2407.16479","DOIUrl":"https://doi.org/arxiv-2407.16479","url":null,"abstract":"Aims. The space radiation environment conditions and the maximum expected\u0000coronal mass ejection (CME) speed are being assessed through the investigation\u0000of scaling laws between the peak proton flux and fluence of Solar Energetic\u0000Particle (SEP) events with the speed of the CMEs. Methods. We utilize a\u0000complete catalog of SEP events, covering the last ~25 years of CME observations\u0000(i.e. 1997 to 2017). We calculate the peak proton fluxes and integrated event\u0000fluences for those events reaching an integral energy of up to E> 100 MeV,\u0000covering the period of the last ~25 years of CME observations. For a sample of\u000038 strong SEP events, we first investigate the statistical relations between\u0000the recorded peak proton fluxes (IP) and fluences (FP) at a set of integral\u0000energies of E >10 MeV, E>30 MeV, E>60 MeV, and E>100 MeV versus the projected\u0000CME speed near the Sun (VCME) obtained by the Solar and Heliospheric\u0000Observatory/Large Angle and Spectrometric Coronagraph (SOHO/LASCO). Based on\u0000the inferred relations, we further calculate the integrated energy dependence\u0000of both IP and FP, assuming that they follow an inverse power-law with respect\u0000to energy. By making use of simple physical assumptions, we combine our derived\u0000scaling laws to estimate the upper limits for VCME, IP, and FP focusing on two\u0000cases of known extreme SEP events that occurred on February 23, 1956 (GLE05)\u0000and in AD774/775, respectively. Given physical constraints and assumptions,\u0000several options for the upper limit VCME, associated with these events, are\u0000investigated. Results. A scaling law relating IP and FP to the CME speed as\u0000V^{5}CME for CMEs ranging between ~3400-5400 km/s is consistent with values of\u0000FP inferred for the cosmogenic nuclide event of AD774/775. At the same time,\u0000the upper CME speed that the current Sun can provide possibly falls within an\u0000upper limit of VCME <= 5500 km/s.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782557","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}

引用次数: 0

Three-Dimensional Venus Cloud Structure Simulated by a General Circulation Model 大气环流模型模拟的三维金星云层结构

arXiv - PHYS - Space Physics Pub Date : 2024-07-22 DOI: arxiv-2407.15966

Wencheng D. Shao, João M. Mendonça, Longkang Dai

{"title":"Three-Dimensional Venus Cloud Structure Simulated by a General Circulation Model","authors":"Wencheng D. Shao, João M. Mendonça, Longkang Dai","doi":"arxiv-2407.15966","DOIUrl":"https://doi.org/arxiv-2407.15966","url":null,"abstract":"The clouds have a great impact on Venus's energy budget and climate\u0000evolution, but its three-dimensional structure is still not well understood.\u0000Here we incorporate a simple Venus cloud physics scheme into a flexible GCM to\u0000investigate the three-dimensional cloud spatial variability. Our simulations\u0000show good agreement with observations in terms of the vertical profiles of\u0000clouds and H2SO4 vapor. H2O vapor is overestimated above the clouds due to\u0000efficient transport in the cloud region. The cloud top decreases as latitude\u0000increases, qualitatively consistent with Venus Express observations. The\u0000underlying mechanism is the combination of H2SO4 chemical production and\u0000meridional circulation. The mixing ratios of H2SO4 at 50-60 km and H2O vapors\u0000in the main cloud deck basically exhibit maxima around the equator, due to the\u0000effect of temperature's control on the saturation vapor mixing ratios of the\u0000two species. The cloud mass distribution is subject to both H2SO4 chemical\u0000production and dynamical transport and shows a pattern that peaks around the\u0000equator in the upper cloud while peaks at mid-high latitudes in the middle\u0000cloud. At low latitudes, H2SO4 and H2O vapors, cloud mass loading and acidity\u0000show semidiurnal variations at different altitude ranges, which can be\u0000validated against future missions. Our model emphasizes the complexity of the\u0000Venus climate system and the great need for more observations and simulations\u0000to unravel its spatial variability and underlying atmospheric and/or geological\u0000processes.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785981","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}

引用次数: 0

Reinterpretation of the Fermi acceleration of cosmic rays in terms of the ballistic surfing acceleration in supernova shocks 用超新星冲击中的弹道冲浪加速度重新解释宇宙射线的费米加速度

arXiv - PHYS - Space Physics Pub Date : 2024-07-22 DOI: arxiv-2407.15767

Krzysztof Stasiewicz

{"title":"Reinterpretation of the Fermi acceleration of cosmic rays in terms of the ballistic surfing acceleration in supernova shocks","authors":"Krzysztof Stasiewicz","doi":"arxiv-2407.15767","DOIUrl":"https://doi.org/arxiv-2407.15767","url":null,"abstract":"The applicability of first-order Fermi acceleration in explaining the cosmic\u0000ray spectrum has been reexamined using recent results on shock acceleration\u0000mechanisms from the Multiscale Magnetospheric mission in Earth's bow shock. It\u0000is demonstrated that the Fermi mechanism is a crude approximation of the\u0000ballistic surfing acceleration (BSA) mechanism. While both mechanisms yield\u0000similar expressions for the energy gain of a particle after encountering a\u0000shock once, leading to similar power-law distributions of the cosmic ray energy\u0000spectrum, the Fermi mechanism is found to be inconsistent with fundamental\u0000equations of electrodynamics. It is shown that the spectral index of cosmic rays is determined by the\u0000average magnetic field compression rather than the density compression, as in\u0000the Fermi model. It is shown that the knee observed in the spectrum at an\u0000energy of 5x10^{15} eV could correspond to ions with a gyroradius comparable to\u0000the size of shocks in supernova remnants. The BSA mechanism can accurately\u0000reproduce the observed spectral index s = -2.5 below the knee energy, as well\u0000as a steeper spectrum, s = -3, above the knee. The acceleration time up to the\u0000knee, as implied by BSA, is on the order of 300 years. First-order Fermi acceleration does not represent a physically valid\u0000mechanism and should be replaced by ballistic surfing acceleration in\u0000applications or models related to quasi-perpendicular shocks in space. It is\u0000noted that BSA, which operates outside of shocks, was previously misattributed\u0000to shock drift acceleration (SDA), which operates within shocks.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782558","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}

引用次数: 0

Nonparametric Statistics on Magnetic Properties at the Footpoints of Erupting Magnetic Flux Ropes 喷发磁通量绳索脚点磁特性的非参数统计

arXiv - PHYS - Space Physics Pub Date : 2024-07-21 DOI: arxiv-2407.15148

Rui Liu, Wensi Wang

{"title":"Nonparametric Statistics on Magnetic Properties at the Footpoints of Erupting Magnetic Flux Ropes","authors":"Rui Liu, Wensi Wang","doi":"arxiv-2407.15148","DOIUrl":"https://doi.org/arxiv-2407.15148","url":null,"abstract":"It is under debate whether the magnetic field in the solar atmosphere carries\u0000neutralized electric currents; particularly, whether a magnetic flux rope\u0000(MFR), which is considered the core structure of coronal mass ejections,\u0000carries neutralized electric currents. Recently Wang et al. (2023, ApJ, 943,\u000080) studied magnetic flux and electric current measured at the footpoints of 28\u0000eruptive MFRs from 2010 to 2015. Because of the small sample size, no rigorous\u0000statistics has been done. Here, we include 9 more events from 2016 to 2023 and\u0000perform a series of nonparametric statistical tests at a significance level of\u00005%. The tests confirm that there exist no significant differences in magnetic\u0000properties between conjugated footpoints of the same MFR, which justifies the\u0000method of identifying the MFR footpoints through coronal dimming. The tests\u0000demonstrate that there exist no significant differences between MFRs with\u0000pre-eruption dimming and those with only post-eruption dimming. However, there\u0000is a medium level of association between MFRs carrying substantial net current\u0000and those produce pre-eruption dimming, which can be understood by the\u0000Lorentz-self force of the current channel. The tests also suggest that in\u0000estimating the magnetic twist of MFRs, it is necessary to take into account the\u0000spatially inhomogeneous distribution of electric current density and magnetic\u0000field.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782559","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}

引用次数: 0

Magnetic Reconnection on a Klein Bottle 克莱因瓶上的磁性再连接

arXiv - PHYS - Space Physics Pub Date : 2024-07-19 DOI: arxiv-2407.14665

Luke Xia, M. Swisdak

引用次数: 0

MLMT-CNN for Object Detection and Segmentation in Multi-layer and Multi-spectral Images 用于多层和多光谱图像中物体检测与分割的 MLMT-CNN

arXiv - PHYS - Space Physics Pub Date : 2024-07-19 DOI: arxiv-2407.14473

Majedaldein Almahasneh, Adeline Paiement, Xianghua Xie, Jean Aboudarham

{"title":"MLMT-CNN for Object Detection and Segmentation in Multi-layer and Multi-spectral Images","authors":"Majedaldein Almahasneh, Adeline Paiement, Xianghua Xie, Jean Aboudarham","doi":"arxiv-2407.14473","DOIUrl":"https://doi.org/arxiv-2407.14473","url":null,"abstract":"Precisely localising solar Active Regions (AR) from multi-spectral images is\u0000a challenging but important task in understanding solar activity and its\u0000influence on space weather. A main challenge comes from each modality capturing\u0000a different location of the 3D objects, as opposed to typical multi-spectral\u0000imaging scenarios where all image bands observe the same scene. Thus, we refer\u0000to this special multi-spectral scenario as multi-layer. We present a multi-task\u0000deep learning framework that exploits the dependencies between image bands to\u0000produce 3D AR localisation (segmentation and detection) where different image\u0000bands (and physical locations) have their own set of results. Furthermore, to\u0000address the difficulty of producing dense AR annotations for training\u0000supervised machine learning (ML) algorithms, we adapt a training strategy based\u0000on weak labels (i.e. bounding boxes) in a recursive manner. We compare our\u0000detection and segmentation stages against baseline approaches for solar image\u0000analysis (multi-channel coronal hole detection, SPOCA for ARs) and\u0000state-of-the-art deep learning methods (Faster RCNN, U-Net). Additionally, both\u0000detection a nd segmentation stages are quantitatively validated on artificially\u0000created data of similar spatial configurations made from annotated multi-modal\u0000magnetic resonance images. Our framework achieves an average of 0.72 IoU\u0000(segmentation) and 0.90 F1 score (detection) across all modalities, comparing\u0000to the best performing baseline methods with scores of 0.53 and 0.58,\u0000respectively, on the artificial dataset, and 0.84 F1 score in the AR detection\u0000task comparing to baseline of 0.82 F1 score. Our segmentation results are\u0000qualitatively validated by an expert on real ARs.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141738203","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}

引用次数: 0

Propagation of Interplanetary Shocks in the Heliosphere 星际冲击在日光层中的传播

arXiv - PHYS - Space Physics Pub Date : 2024-07-17 DOI: arxiv-2407.12689

Munkhjargal Lkhagvadorj, Gabor Facsko, Andrea Opitz, Peter Kovacs, David G. Sibeck

{"title":"Propagation of Interplanetary Shocks in the Heliosphere","authors":"Munkhjargal Lkhagvadorj, Gabor Facsko, Andrea Opitz, Peter Kovacs, David G. Sibeck","doi":"arxiv-2407.12689","DOIUrl":"https://doi.org/arxiv-2407.12689","url":null,"abstract":"Interplanetary shocks are one of the crucial dynamic phenomena in the\u0000Heliosphere. They accelerate particles to high energies, generate plasma waves,\u0000and can trigger geomagnetic storms in the terrestrial magnetosphere disturbing\u0000significantly our technological infrastructures. In this study, two IP shock\u0000events are selected to study the temporal variations of the shock parameters\u0000using magnetometer and ion plasma measurements of the STEREO$-$A and B, the\u0000Wind, Cluster fleet, and the ACE spacecraft. The shock normal vectors are\u0000determined using the minimum variance analysis (MVA) and the magnetic\u0000coplanarity methods. During the May 7, 2007 event, the shock parameters and the\u0000shock normal direction are consistent. The shock surface appears to be tilted\u0000almost the same degree as the Parker spiral, and the driver could be a\u0000Co--Rotating Interacting Region (CIR). During the April 23, 2007 event, the\u0000shock parameters do not change significantly except for the shock $theta_{Bn}$\u0000angle, however, the shape of the IP shock appears to be twisted along the\u0000perpendicular direction to the Sun-Earth line as well. The driver of this\u0000rippled shock is Stream Interaction Regions (SIRs)/CISs as well.","PeriodicalId":501423,"journal":{"name":"arXiv - PHYS - Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141738200","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}

引用次数: 0

Simultaneous Proton and Electron Energization during Macroscale Magnetic Reconnection 大尺度磁重联过程中质子和电子的同时激发

arXiv - PHYS - Space Physics Pub Date : 2024-07-15 DOI: arxiv-2407.10933

Zhiyu Yin, James F. Drake, Marc Swisdak

引用次数: 0