Abstract The largest geomagnetic storm in two decades occurred 2024 May with a minimum D st of −412 nT. We examine its solar and interplanetary origins by combining multipoint imaging situ observations. source active region, NOAA AR 13664, exhibited extraordinary activity produced successive halo eruptions, which were responsible for complex ejecta observed at the Earth. In measurements from STEREO A, was 12.°6 apart, allow us to compare “geo-effectiveness” Earth A. obtain key findings...

Abstract We report on the first direct in situ measurements of a fast coronal mass ejection (CME) and shock corona, which occurred 2022 September 5. In from Parker Solar Probe spacecraft near perihelion suggest two shocks, with second one decayed, is consistent more than eruption coronagraph images. Despite flank crossing, indicate unique features young ejecta: plasma much hotter ambient medium, suggestive hot solar source, large β implying highly non-force-free state importance thermal...

Abstract A powerful coronal mass ejection (CME) occurred on 2017 September 10 near the end of declining phase historically weak solar cycle 24. We obtain new insights concerning geometry and kinematics CME-driven shocks in relation to their heliospheric impacts from optimal, multispacecraft observations eruption. The shock, which together with CME driver can be tracked early stage outer corona, shows a large oblate structure produced by vast expansion ejecta. speeds shock along radial...

An unexpected strong geomagnetic storm occurred on 2018 August 26, which was caused by a slow coronal mass ejection (CME) from gradual eruption of large quiet-region filament. We investigate the and propagation characteristics this CME in relation to with remote sensing situ observations. Coronal magnetic fields around filament are extrapolated compared EUV determine direction tilt angle flux rope near Sun using graduated cylindrical shell (GCS) model Sun-to-Earth kinematics wide-angle...

The pore characteristics of tight sandstones are great significance for studying the size distribution, surface roughness and seepage mechanism. In order to evaluate distribution comprehensive fractal sandstone in Y Basin, structure is characterised by low temperature nitrogen adsorption (LTNA) high pressure mercury intrusion (HPMI), fractals different scales fitted calculated. We calculate dimension based on full-scale map discuss difference from shale Qinshui Basin. Finally, we also...

NOAA active region (AR) 13664/8 produced the most intense geomagnetic effects since Halloween event of 2003. The resulting extreme solar storm is thought to be consequence multiple interacting coronal mass ejections (CMEs). Notably, this AR exhibits exceptionally rapid magnetic flux emergence. eruptions on which we focus all occurred along collisional polarity inversion lines (PILs) through shearing during a three-day period extraordinarily high emergence (sim 1021 Mx hr$^ $). Our key...

Abstract As an important source for large geomagnetic storms, “ICME-in-sheath” is a completely shocked interplanetary coronal mass ejection (ICME) stuck in the sheath between shock and host ejecta. Typical characteristics are identified from coordinated multi-sets of observations: (1) it usually short duration lasts few hours at 1 au; (2) its solar wind parameters, particular magnetic field, seem to keep enhanced range distances; (3) common ICME signatures often lost. The ejecta could be...

Abstract Soft X-ray emissions from solar wind charge exchange (SWCX) are applied in a recently developed approach to study the magnetosphere using panoramic soft imaging. This represents first attempt distinguish magnetospheric SWCX observed by XMM-Newton during impact of an interplanetary coronal mass ejection (ICME) and its driven sheath on Earth. In addition, data Advanced Composition Explorer (ACE) were available this same observational period, which is rare previous studies. Results...

Abstract We present an investigation of the rotation and nonradial motion a coronal mass ejection (CME) from AR 12468 on 2015 December 16 using observations SDO , SOHO STEREO A Wind . The EUV HMI source region show that associated magnetic flux rope (MFR) axis pointed to east before eruption. use nonlinear force-free field (NLFFF) extrapolation determine configuration calculate energy density distributions at different heights. distribution shows strong gradient toward northeast. propagation...

In this paper, we establish a new non-dimensional global geomagnetic disturbance index JpG by applying the spectral whitening method to horizontal components of fields observed at eight ground-based stations distributed low and middle latitudes during years 1998 2014. This can describe development storms its relationship with Dst has been verified, which gives correlation coefficient (CC) about 0.72. We also check response arrival upstream solar wind energy based on proxy that ring current...

We investigate how a weak coronal mass ejection (CME) launched on 2016 October 8 without obvious signatures in the low corona produced relatively intense geomagnetic storm. Remote sensing observations from SDO, STEREO and SOHO situ measurements WIND are employed to track CME Sun Earth. Using graduated cylindrical shell (GCS) model, we estimate propagation direction morphology of near Sun. kinematics determined wide-angle imaging A used predict arrival time speed at compare ENLIL MHD...

Sap flux (Ft) measurements are extensively used to scale-up canopy transpiration and conductance, but time lag between sap is a problem. As nearly synchronous with micrometeorological drivers, better understanding of the relationships Ft drivers soil water conditions would benefit up-scaling from flux. Time series modeling at different spatial temporal scales can identify incorporate effects, as well multiple variables affecting interactions them. SARIMAX GARCH hybrid models were capture...

In order to have a comprehensive view of the propagation and evolution coronal mass ejections (CMEs) from Sun deep interplanetary space beyond 1 au, we carry out kinematic analysis 7 CMEs in solar cycle 23. The events are required coordinated coronagraph observations, type II radio bursts, multi-point in-situ measurements at Earth Ulysses. A graduated cylindrical shell model, an analytical model without free parameters magnetohydrodynamic used derive CME kinematics near Sun, quantify...

Propagation of coronal mass ejections (CMEs) from the Sun far into interplanetary space is not well understood due to limited observations. In this study we examine propagation characteristics two geo-effective CMEs, which occurred on 2005 May 6 and 13, respectively. Significant heliospheric consequences associated with CMEs are observed, including (ICMEs) at Earth Ulysses, shocks, a long-duration type II radio burst, intense geomagnetic storms. We use coronagraph observations SOHO/LASCO,...

Abstract Small-scale eruptions could play an important role in coronal heating, generation of solar energetic particles (SEPs), and mass source the wind. However, they are poorly observed, their characteristics, distributions, origins remain unclear. Here a mini dimming was captured by recently launched Solar Orbiter spacecraft. The observations indicate that minifilament eruption results takes away approximately (1.65 ± 0.54) × 10 13 g mass, which also exhibits similar features as sources...

It is paramount from both scientific and societal perspectives to understand the generation of extreme space weather. We discuss formation solar superstorms based on a comparative study 2012 July 23 2017 eruptions. The first one Carrington-class, second could rival 1989 March event that caused most intense geomagnetic storm age. Observations these events in historically weak cycle 24 indicate superstorm can occur any at phase cycle. Recurrent patterns are identified cases, including...

Abstract Accurate model predictions of the tree sap flux in sapwood are critical for forestry water management, primarily due to data availability limitations. Time series models have been used analyses since 2005. Classic autoregressive such as ARIMA (autoregressive integrated moving average), ARIMAX (ARIMA with exogenous variables), SARIMA (seasonal ARIMA) and SARIMAX ARIMAX) designed tested two common exotic species (Eucalyptus citriodora Hook. f. Acacia auriculaeformis A. Chun) dry wet...

Abstract We investigate the coronal and interplanetary evolution of a mass ejection (CME) launched on 2010 September 4 from source region linking two active regions (ARs), 11101 11103, using extreme ultraviolet imaging, magnetogram, white-light, in situ observations SDO , STEREO SOHO VEX Wind . A potential-field source-surface model is employed to examine configuration magnetic field surrounding region. The graduated cylindrical shell triangulation method are applied determine kinematics CME...

We examine the propagation and interaction properties of three successive coronal mass ejections (CMEs) from 2001 November 21-22, with a focus on their connection behaviors associated long-duration complex type II radio burst. In combination coronagraph multi-point in situ observations, burst provides key features for resolving complexities CMEs. The two CMEs 22 interacted first then overtook 21 CME at distance about 0.85 AU Sun. time scale shock originally driven by last to propagate...

Plant-water relations have been of significant concern in forestry and ecology studies recent years, yet investigating the annual differences characteristics inter-class water consumption trees are scarce.We classified 15 from a Schima superba plantation subtropical South China into four ranks using diameter at breast height (DBH). The whole-tree use were compared based on three parameters: sap flux density, transpiration canopy over two years. Inter-class hydraulic parameters, such as leaf...

We report on the first direct in situ measurements of a fast coronal mass ejection (CME) and shock corona, which occurred 2022 September 5. In from Parker Solar Probe (PSP) spacecraft near perihelion suggest two shocks with second one decayed, is consistent more than eruptions coronagraph images. Despite flank crossing, indicate unique features young ejecta: plasma much hotter ambient medium suggestive hot solar source, large $\beta$ implying highly non-force-free state importance thermal...

Background The hilly region of the central Sichuan basin is one most severely affected areas in China terms soil and water loss. For this reason, a large area mixed alder cypress forest has been established for protection. However, uneven distribution rainfall significantly impacts stability usage plantations. Therefore, accurately understanding response trees to real-time essential effective forests management that optimizes hydrology resources. Aims To examine how sap flux responds...

Abstract We develop a preliminary interplanetary disturbance index ( J <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow/> <mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> mathvariant="normal">W</mml:mi> </mml:msubsup> </mml:math> ) by applying the spectral whitening method to an energy coupling function with solar wind measurements during years 1998–2014 as input, which can be used indicator of perturbations in near-Earth wind....