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This study reports comprehensive observations for the G5-level geomagnetic storm that occurred from May 10 to 12, 2024, the most intense event since the 2003 Halloween storm. The storm was triggered by a series of coronal mass ejections (CMEs) originating from the merging of two active regions 13664/13668, which formed a large and complex photospheric magnetic configuration and produced X-class flares in early May 2024. Among the events, the most significant CME, driven by an X2.2 flare on May 9, caught up with and merged with a preceding slower CME associated with an X-class flare on May 8. These combined CMEs reached 1 AU simultaneously, resulting in an extreme geomagnetic storm. Geostationary satellite observations revealed changes in Earth’s magnetosphere due to solar wind impacts, increased fluxes of high-energy particles, and periodic magnetic field fluctuations accompanied by particle injections. Extreme geomagnetic storms resulting from the interaction of the solar wind with the Earth’s magnetosphere caused significant energy influx into Earth’s upper atmosphere over the polar regions, leading to thermospheric heating and changes in the global atmospheric composition and ionosphere. As part of this global disturbance, significant disruptions were also observed in the East Asian sector, including the Korean Peninsula. Ground-based observations show strong negative storm effects in the ionosphere, which are associated with thermospheric heating and resulting in decreases in the oxygen-to-nitrogen ratio (O/N2) in high-latitude regions. Global responses of storm-time prompt penetration electric fields were also observed from magnetometers over the East-Asian longitudinal sector. We also briefly report storm-time responses of aurora and cosmic rays using all-sky cameras and neutron monitors operated by the Korea Astronomy and Space Science Institute (KASI). The extensive observations of the G5-level storm offer crucial insights into Sun-Earth interactions during extreme space weather events and may help establish better preparation for future space weather challenges.

Objectives “Environmental Blindspots” are newly defined as a type of social problem within the realm of various environmental pollution and climate issues, wherein they are pushed down in priority due to factors such as corporate profit, consumer preferences, and government regulations, consequently remaining unresolved. This ultimately leads citizens to experience a sense of guilt. Despite the significant influence they wield on the welfare of current and future generations, various environmental social issues characterized by environmental blindspots (such as micro-hazardous substances like microplastics and environmental hormones) fail to become major considerations in societal decision-making. Consequently, they are not actively discussed within the social community. This absence of social consensus on these issues reflects the current situation. As a result, citizens repeatedly make choices that do not prioritize environmental values due to a perception of powerlessness stemming from the absence of environmentally friendly options, the belief that the issue is too immense to tackle individually, and lack of knowledge about specific actions to take for environmental problem-solving, among other factors. In this process, they experience involuntary and deliberate emotions of guilt. Since environmental blindspots are issues collectively experienced by the societal community comprising citizens, businesses, and government, solutions must also be derived collectively through collective thinking. This review has endeavored to incorporate such efforts. Methods In this review, to develop a more effective interdisciplinary research methodology for addressing the previously mentioned environmental social issues, ten interdisciplinary researchers from the Environmental Engineering and Social Sciences fields at the center for convergence research (SEBIS) collaborated, leveraging their respective expertise to document literature survey results. Firstly, they reported on the environmental behavior, toxicity, distribution, and regulatory status of micro-hazardous substances, namely (micro)plastics and volatile organic compounds, which are the research subjects of the Environmental Blindspot Research Center. Secondly, they compiled relevant treatment technologies. Subsequently, they described the socio-structural causes of environmental blindspots and various solutions to environmental social issues through social science methodologies. Results and Discussion To address the environmental blindspots, a key environmental social issue, it is necessary to advance various environmental technologies alongside responsible production by businesses and the enhancement of citizen environmental awareness. It is crucial for the government to institutionalize policies in the public domain to achieve this. Understanding the structural roles of citizens, businesses, and government is essential. It requires ethical consumer awareness and active participation, public campaigns and education, as well as effective government environmental policies to incentivize environmental friendly technological innovations by companies. Conclusion In this review, the issue of environmental blindspots as an environmental social issue is being addressed comprehensively for the first time. Through this, we aim to establish an effective communication and cooperation system among social entities to explore solutions to environmental blindspots, and to propagate this ability to address social issues to future academic generations.

The Korean heliospheric community, led by the Korea Astronomy and Space Science Institute (KASI), is currently assessing the viability of deploying a spacecraft at the Sun-Earth Lagrange Point L4 in collaboration with National Aeronautics and Space Administration (NASA). The aim of this mission is to utilize a combination of remote sensing and in situ instruments for comprehensive observations, complementing the capabilities of the L1 and L5 observatories. The paper outlines longterm scientific objectives, underscoring the significance of multi-point in-situ observations to better understand critical heliospheric phenomena. These include coronal mass ejections, magnetic flux ropes, heliospheric current sheets, kinetic waves and instabilities, suprathermal electrons and solar energetic particle events, as well as remote detection of solar radiation phenomena. Furthermore, the mission’s significance in advancing space weather prediction and space radiation exposure assessment models through the integration of L4 observations is discussed. This article is concluded with an emphasis on the potential of L4 observations to propel advancements in heliospheric science.

Abstract Mutual conversion of various kinds of magnetohydrodynamic (MHD) waves can have profound impacts on wave propagation, energy transfer, and heating of the solar chromosphere and corona. Mode conversion occurs when an MHD wave travels through a region where the Alfvén and sound speeds are equal (e.g., a 3D magnetic null point). Here we report the direct extreme ultraviolet (EUV) imaging of mode conversion from a fast-mode to a slow-mode MHD wave near a 3D null point using Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) observations. An incident fast EUV wavefront associated with an adjacent eruptive flare propagates laterally through a neighboring pseudostreamer. Shortly after the passage of the fast EUV wave through the null point, a slow-mode wave appears near the null that propagates upward along the open structures and simultaneously downward along the separatrix encompassing the fan loops of the pseudostreamer base. These observations suggest the existence of mode conversion near 3D nulls in the solar corona, as predicted by theory and MHD simulations. Moreover, we observe decaying transverse oscillations in both the open and closed structures of the pseudostreamer, along with quasiperiodic type III radio bursts indicative of repetitive episodes of electron acceleration.

We study properties of intensity disturbances along polar coronal rays that are associated with plumes below. For this, we draw azimuth–time images of extreme ultraviolet (EUV) emission of 171 Å band observed by the SDO/AIA and white light (WL) observed by the SOHO/LASCO C2 in 2020 July. From the azimuth–time image, we define two tracks in which the EUV intensities were recurrently enhanced during two weeks. The two EUV tracks are rooted at 78.°8 and 81.°4 latitudes, but their projected azimuth angles are changed with time as the Sun rotates. Coherent WL tracks at different altitudes are determined by scaling the azimuth angles of the EUV tracks, accounting for the effect of inclination of coronal rays. From this, we construct time–distance images of WL intensities along WL tracks, whose projected azimuth angle changes along time and altitude, but the intensities are correlated with the EUV intensities measured below. The time–distance images of WL show repeated and inclined intensity features. The propagation speeds in the altitude range 2.3–6 solar radii are calculated to be 159 ± 8 km s ^−1 and 300 ± 24 km s ^−1 . The EUV and WL intensities are found to be coherent at 1–2 day periods. It is also found that dynamic burst events along the EUV track are responsible for the enhanced emission. We conclude that the variation of the WL intensity along the polar coronal rays is related with the evolution of the EUV intensity below.