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The Solar and Heliospheric Observatory (SOHO) mission's white light
coronagraphs have observed nearly 7000 coronal mass ejections (CMEs)
between 1996 and 2002. We have documented the measured properties of all
these CMEs in an online catalog. We describe this catalog and present a
summary of the statistical properties of the CMEs. The primary
measu...
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Context 1
... In order to investigate the properties of CMEs with different angular widths, we simply grouped CMEs into three populations: narrow (W 20°), normal (20° < W 120°), and wide (W > 120°) CMEs (From the bimodal distribution during early solar maximum, we can discern a population of narrow CMEs with W 20°. The CMEs with W > 120° are called partial halos). The numbers and fractions of narrow, normal, and wide CMEs in each year are shown in Table 2. We found that the fraction of narrow CMEs increases toward solar maximum. ...
Similar publications
Coronal mass ejections (CMEs) and their interplanetary counterparts (interplanetary coronal mass ejections, ICMEs) are responsible for large solar energetic particle events and severe geomagnetic storms. They can modulate the intensity of Galactic cosmic rays, resulting in non-recurrent Forbush decreases (FDs). We investigate the connection between...
Citations
... This work made use of the radio dynamic spectra from Wind, STEREO-A and STEREO-B spacecraft in the frequency range 0.02 -14 MHz. The properties of the white-light CMEs observed by Large Angle and Spectrometric COronagraph (LASCO; Brueckner et al. 1995) onboard Solar and Heliospheric Observatory 2 (SOHO) are obtained from the LASCO CME catalog (Yashiro et al. 2004;Gopalswamy et al. 2009). We relied on the event reports from Space Weather Prediction Center 3 (SWPC) to obtain the list of metric type-IV events since 1996. ...
... The date-time interval we chose for the study extends from Nov, 1996 to May, 2023, which is when LASCO data started being available. This ensures that we have a well defined, systematically compiled catalog of CME characteristics covering multiple solar cycles (Yashiro et al. 2004;Gopalswamy et al. 2009). The final list of DH type-IVs search periods include date-times corresponding to 34083 LASCO CMEs, 939 metric type-IVs and 140 DH type-IIs. ...
Decameter hectometric (DH; 1-14 MHz) type-IV radio bursts are produced by flare-accelerated electrons trapped in post-flare loops or the moving magnetic structures associated with the CMEs. From a space weather perspective, it is important to systematically compile these bursts, explore their spectro-temporal characteristics, and study the associated CMEs. We present a comprehensive catalog of DH type-IV bursts observed by the Radio and Plasma Wave Investigation (WAVES) instruments onboard Wind and STEREO spacecraft, covering the period of white-light CME observations by the Large Angle and Spectrometric Coronagraph (LASCO) onboard the SOHO mission between November 1996 and May 2023. The catalog has 139 bursts, of which 73% are associated with a fast (>900 km/s) and wide (>60$^o$) CME, with a mean CME speed of 1301 km/s. All DH type-IV bursts are white-light CME-associated, with 78% of the events associated with halo CMEs. The CME source latitudes are within $\pm$45$^o$. 77 events had multi-vantage point observations from different spacecraft, letting us explore the impact of line of sight on the dynamic spectra. For 48 of the 77 events, there was good data from at least two spacecraft. We find that, unless occulted by nearby plasma structures, a type-IV burst is best viewed when observed within $\pm$60$^o$ line of sight. Also, the bursts with a duration above 120 min, have source longitudes within $\pm$60$^o$. Our inferences confirm the inherent directivity in the type-IV emission. Additionally, the catalog forms a sun-as-a-star DH type-IV burst database.
... As a widely adopted catalog maintained manually at Coordinated Data Analysis Workshops' (CDAW; Yashiro et al. 2004) data center, it is time-consuming and may be subjective, particularly during times of high solar activity. The shortcomings of manual catalogs have led to the development of automated methods for detecting and tracking CMEs. ...
Coronal mass ejections (CMEs) are major drivers of geomagnetic storms, which may cause severe space weather effects. Automating the detection, tracking, and three-dimensional (3D) reconstruction of CMEs is important for operational predictions of CME arrivals. The COR1 coronagraphs on board the Solar Terrestrial Relations Observatory spacecraft have facilitated extensive polarization observations, which are very suitable for the establishment of a 3D CME system. We have developed such a 3D system comprising four modules: classification, segmentation, tracking, and 3D reconstructions. We generalize our previously pretrained classification model to classify COR1 coronagraph images. Subsequently, as there are no publicly available CME segmentation data sets, we manually annotate the structural regions of CMEs using Large Angle and Spectrometric Coronagraph C2 observations. Leveraging transformer-based models, we achieve state-of-the-art results in CME segmentation. Furthermore, we improve the tracking algorithm to solve the difficult separation task of multiple CMEs. In the final module, tracking results, combined with the polarization ratio technique, are used to develop the first single-view 3D CME catalog without requiring manual mask annotation. Our method provides higher precision in automatic 2D CME catalog and more reliable physical parameters of CMEs, including 3D propagation direction and speed. The aforementioned 3D CME system can be applied to any coronagraph data with the capability of polarization measurements.
... To determine the presence of CMEs and their parameters, we used the Coordinated Data Analysis Workshop catalog (CDAW: Yashiro et al., 2004;Gopalswamy et al., 2009). This catalog compiles all CMEs manually identified in LASCO images and provides information about their parameters: speed, angular width, etc. ...
... Firstly, the observations presented in this work were carried out at solar maximum. At solar minimum, CMEs are less energetic than at solar maximum (Yashiro et al., 2004;Vourlidas et al., 2010). It is probable that, at solar minimum, the percentage of flare-associated CMEs differs from those at solar maximum . ...
... As a result, GOES misses weak flares, which leads to an underestimation of the CME-flare association rate. On the other hand, halo CMEs are faster than average CMEs (Yashiro et al., 2004;Gopalswamy et al., 2010). Therefore, it is reasonable to assume that halo CMEs are mainly associated with strong flares. ...
The association of coronal mass ejections (CMEs) with flares is related to the question of whether reconnection is necessary for the CME eruption. Indeed, if reconnection happens during a CME eruption, the plasma is heated, which can be observed as a flare. In this work, we study the CME-flare association using data obtained with the Mg xii spectroheliograph on board the Complex Orbital Observations Near-Earth of Activity on the Sun (CORONAS-F) satellite. This instrument is sensitive only to the emission of plasma with a temperature greater than 4 MK, which makes it a convenient tool for detection of flaring activity. During our analysis, we first searched for CMEs detected during the Mg xii observations by the Large Angle and Spectroscopic Coronagraph (LASCO). Then, we visually checked the Mg xii images for flaring activity. We found that during the Mg xii observations (2001 – 2003), 198 CMEs were detected by LASCO. One hundred sixty of them (81%) are associated with flares seen in the Mg xii images. The strength of flares associated with narrow CMEs – jet-like ejecta – is uniformly distributed in the A – C GOES class range. The speed of narrow CMEs does not depend on the flare strength. For normal CMEs (motion of both magnetic field and plasma), the flare strength varies from A to X class with a peak of the distribution at the C level. The median speed and the kinetic energy of normal CMEs weakly depend on flare strength for weak flares (below C) and strongly for strong ones (M and X). Our results suggest that at solar maximum reconnection occurs during most CMEs. For strong flares (M and X), the reconnection is a dominant acceleration mechanism. For weak flares (C and below), other mechanisms start to play a bigger role.
... The source (CMEs/flares) onset times and locations, when available, are provided in Table 1. The CME and flare information is based on the SOHO/LASCO CME catalog (Yashiro et al. 2004;Gopalswamy et al. 2009). Information about the CME-associated flares is based on the work of Gopalswamy et al. 2019. ...
... This suggests that the CMEdriven shock was longitudinally wide enough and quickly expanded into the toward sector from the away sector after the eruption. This is highly likely because the typical longitudinal width of CME is ∼50° (Yashiro et al. 2004). Cross-field transport of the SEPs generated at the shock in the toward sector can populate a large area of the toward sector at low latitudes. ...
The effect of the heliospheric current sheet (HCS) on the propagation of solar energetic particles (SEPs) remains poorly known. In this study we address this question by surveying energetic (∼2.0–9.6 MeV nucleon –1 ) helium data acquired by the energetic particle acceleration, composition, and transport (EPACT) sensor on board the Wind spacecraft. A superposed epoch analysis of 319 HCS crossings made by Wind reveals a sharp drop in the SEP fluxes at the HCS for the low-energy channels and little change across the HCS for the high-energy channels. To help understand the statistical result, we studied a total of 15 SEP flux dropout (a decrease of ∼50% or more) events that coincided with the crossing of the HCS. One of the common features of these SEP events is that they were initiated in the western hemisphere but far away from the longitude of HCS crossings, suggesting that the source of SEPs was well connected initially but was cut off later after Wind moved to the opposite hemisphere (e.g., HCS crossing). Further analysis of the events suggests that the percentage of flux dropouts decreases with increasing energy. It is suggested that a strong scattering of MeV helium may have occurred as the particle gyroradius is comparable to the thickness of the current sheet. This study clearly provides solid evidence for the HCS as a barrier to suppressing SEP flux of MeV energies from the onset hemisphere to the other.
... Once the volume is determined, we need the CME mass to calculate the density. This parameter is routinely calculated for all CMEs observed by the LASCO coronagraphs, and it is available in the CDAW CME catalog (Yashiro 2004). A detailed description of the method is provided in Vourlidas et al. (2010). ...
The relationship between CME properties in the corona and their interplanetary counterparts is not well understood. Until recently, a wide spatial gap existed between the two regions, which prevented us from disentangling the spatial and temporal evolution of CMEs. NASA’s Parker Solar Probe (PSP) has imaged multiple CMEs since its launch in 2018, but these events either intercepted the spacecraft far from the corona or completely missed it. Here we describe one of the first CMEs observed simultaneously by remote sensing and in situ instruments, and compare the corresponding measured properties, such as orientation, cross section diameter, density, and speed. The CME encounter occurred on 2022 June 2, while PSP was around 14 solar radii from the Sun center. We reconstruct the CME with forward modeling and determine its morphology and kinematics. The reconstruction suggests that PSP misses the CME apex but encounters its flank. The encounter time matches the period when the PSP in situ measurements indicate the passage of a CME. We also reconstruct the flux rope diameter and orientation using the in situ magnetic field measurements. The results are consistent with the CME reconstruction from imaging data. The close agreement between remote sensing and in situ analyses suggests that discrepancies found in past studies are more likely associated with the CME temporal evolution. We also find that the magnetic field of the CME flank extrapolated to 1 au is well below the average solar wind background and likely indistinguishable from it. This point could explain past events where the CMEs' interplanetary counterparts were not identified.
... Event catalogs can be divided into manual and automatic catalogs. A widely used manual catalog is the SOHO LASCO CME Catalog, 4 maintained at the Coordinated Data Analysis Workshop (CDAW) data center of NASA (Yashiro 2004). The key parameters-e.g., appearance time, central position angle (CPA), angular width (AW), and linear velocity-as well as a short video of every CME recorded are listed (Gopalswamy et al. 2009) in the catalog. ...
Coronal mass ejections (CMEs) constitute the major source of severe space weather events, with the potential to cause enormous damage to humans and spacecraft in space. It is becoming increasingly important to detect and track CMEs, since there are more and more space activities and facilities. We have developed a new algorithm to automatically derive a CME’s kinematic parameters based on machine learning. Our method consists of three steps: recognition, tracking, and the determination of parameters. First, we train a convolutional neural network to classify images from Solar and Heliospheric Observatory Large Angle Spectrometric Coronagraph observations into two categories, containing CME(s) or not. Next, we apply the principal component analysis algorithm and Otsu’s method to acquire binary-labeled CME regions. Then, we employ the track-match algorithm to track a CME’s motion in time-series images and finally determine the CME’s kinematic parameters, e.g., velocity, angular width, and central position angle. The results of four typical CME events with different morphological characteristics are presented and compared with a manual CME catalog and several automatic CME catalogs. Our algorithm shows some advantages in the recognition of CME structure and the accuracy of the kinematic parameters. This algorithm can be helpful for real-time CME warnings and predictions. In the future, this algorithm is capable of being applied to CME initialization in magnetohydrodynamic simulations to study the propagation characteristics of real CME events and to provide more efficient predictions of CMEs’ geoeffectiveness.
... Figure 1 presents the space weather conditions for the period from 24 February to 1 March 2014. We will focus on the moderate geomagnetic storm that occurred on 27-28 February, 2014. Figure 1a illustrates an enhanced proton flux (>10 MeV) due to an X4.9-class flare that occurred on 25 February 2014, along with a halo Coronal Mass Ejection (CME) (Yashiro et al., 2004). Notably, this surge in proton flux surpassed the 10 cm 2 s 1 sr 1 warning level established by the Space Weather Prediction Center of the National Oceanic and Atmospheric Administration (NOAA). ...
Space‐weather conditions can often have a detrimental impact on satellite communications and limited experimental data has made it challenging to understand the complex processes that occur in the upper atmosphere. To overcome this challenge, we utilized a coordinated multi‐instrumental dataset consisting of GNSS airglow remote sensing, ionosonde, magnetometer, and in‐situ satellite data to investigate plasma depletions. We present a case study focused on the geomagnetic storm that occurred on 27 February 2014. During the storm, GNSS positioning errors exceeded undisturbed levels by at least 2 times, and ionospheric corrections reached amplitudes of up to ±20 m at the Rabat station. We identified 3 large depletions that were most likely generated by sudden vertical ionospheric drifts that began at approximately 17:00 UTC at sunset in Morocco and the southern regions of Spain. These drifts reached ∼500 m/s and lasted until 22:00 UTC. The observed depletions propagated to the northeast, as seen through ionosonde echoes and ground‐based airglow images. Satellite limb‐images revealed an ionospheric uplift of about 100 km due to the storm, consistent with ionosondes in Spain. The observed local anomalies may be influenced by variations in equatorial electric current flows, which are correlated with fluctuations in ground‐based magnetometer data. These variations are likely a result of the effects of the inner radiation belt on the development of plasma bubbles in the African longitude sector. Sudden enhancements in upward E × B drift caused ionospheric uplift to higher altitudes, enhancing the “fountain effect” and shifting the Equatorial Ionospheric Anomaly crests to higher latitudes.
... Then, to identify CME physical parameters, we compare the collected CMEs with the SOHO LASCO CME Catalog (Yashiro et al. 2004). The SOHO LASCO CME Catalog (Yashiro et al. 2004) database includes comprehensive parameters for all CMEs detected by SOHO LASCO (Brueckner et al. 1995) since 1996, such as angular width, acceleration, average speed, final speed, estimated mass, and main position angle. ...
... Then, to identify CME physical parameters, we compare the collected CMEs with the SOHO LASCO CME Catalog (Yashiro et al. 2004). The SOHO LASCO CME Catalog (Yashiro et al. 2004) database includes comprehensive parameters for all CMEs detected by SOHO LASCO (Brueckner et al. 1995) since 1996, such as angular width, acceleration, average speed, final speed, estimated mass, and main position angle. Unlike Liu et al. (2018), we include all CMEs, irrespective of their angular width, after excluding those without final speed measurements, resulting in 243 geoeffective CMEs. ...
... Accessing the geoeffectiveness of CME is critical for studying its arrival time and other space weather tasks. Therefore, the second step in future work is to predict if the CME would reach the Earth for all CME events listed in the SOHO LASCO CME catalog (Yashiro et al. 2004). Finally, we intend to introduce more refined predictions in later research that consider the connection between CME and other strong solar activities, such as M-level or higher solar flares, to minimize the potential damage of solar activity to the Earth. ...
Coronal mass ejections (CMEs) are among the most intense phenomena in the Sun–Earth system, often resulting in space environment effects and consequential geomagnetic disturbances. Consequently, quickly and accurately predicting CME arrival time is crucial to minimize the harm caused to the near-Earth space environment. To forecast the arrival time of CMEs, researchers have developed diverse methods over the years. While existing approaches have yielded positive results, they do not fully use the available data, as they solely accept either CME physical parameters or CME images as inputs. To solve this issue, we propose a method that extracts features from both CME physical parameters and CME images and uses the attention mechanism to fuse the two types of data. First, we design a parameter feature extraction module that extracts features from CME physical parameters. After that, we adopt an effective convolutional neural network model as our image feature extraction module for extracting features from CME images. Finally, utilizing the attention mechanism, we present a feature fusion module designed to fuse the features extracted from both parameters and images of CMEs. Therefore, our model can fully utilize and combine physical parameters and image features, which allows it to capture significant and comprehensive information about CMEs.
... For jets, they estimated values using rates in polar coronal holes given by Savcheva et al. (2007). Similarly, flare and CME rates, along with flare durations, were used to make estimates for the number of large-scale eruptions occurring on the Sun at any time (Veronig et al. 2002;Yashiro et al. 2004;Chen 2011). Considering the extent of the ranges of the values for the measured or estimated quantities (which take the place of "error bars" on the plot), a best-fit line to all three of these points showed that those three values are consistent with following a power law. ...
We consider small-scale jetlike events that might make the solar wind, as has been suggested in recent studies. We show that the events referred to as “coronal jets” and as “jetlets” both fall on a power-law distribution that also includes large-scale eruptions and spicule-sized features; all of the jetlike events could contribute to the solar wind. Based on imaging and magnetic field data, it is plausible that many or most of these events might form by the same mechanism: Magnetic flux cancelation produces small-scale flux ropes, often containing a cool-material minifilament. This minifilament/flux rope erupts and reconnects with adjacent open coronal field, along which “plasma jets” flow and contribute to the solar wind. The erupting flux ropes can contain twist that is transferred to the open field, and these become Alfvénic pulses that form magnetic switchbacks, providing an intrinsic connection between switchbacks and the production of the solar wind.
... Estimates for the bright front have been 45°-70° (Hundhausen 1993;St. Cyr et al. 2000b;Yashiro et al. 2004), excluding partial and full halo. There has not been any dedicated statistical work on the latitudinal width of the dark cavity, as far as we are aware. ...
... We start our analysis by identifying all partial and full halo CMEs observed by LASCO (Brueckner et al. 1995) and STEREO/SECCHI/COR2 (Howard et al. 2008). To do so, we use the SOHO/LASCO catalog (Yashiro et al. 2004) and the COR2 CACTUS automatic catalog (Robbrecht & Berghmans 2004). For the LASCO catalog, we start from all CMEs with an angular width larger than 120°. ...
Coronal mass ejections (CMEs) are large-scale eruptions with a typical radial size at 1 au of 0.21 au but their angular width in interplanetary space is still mostly unknown, especially for the magnetic ejecta (ME) part of the CME. We take advantage of STEREO-A angular separation of 20°–60° from the Sun–Earth line from 2020 October to 2022 August, and perform a two-part study to constrain the angular width of MEs in the ecliptic plane: (a) we study all CMEs that are observed remotely to propagate between the Sun–STEREO-A and the Sun–Earth lines and determine how many impact one or both spacecraft in situ, and (b) we investigate all in situ measurements at STEREO-A or at L1 of CMEs during the same time period to quantify how many are measured by the two spacecraft. A key finding is that out of 21 CMEs propagating within 30° of either spacecraft only four impacted both spacecraft and none provided clean magnetic cloud-like signatures at both spacecraft. Combining the two approaches, we conclude that the typical angular width of an ME at 1 au is ∼20°–30°, or 2–3 times less than often assumed and consistent with a 2:1 elliptical cross section of an ellipsoidal ME. We discuss the consequences of this finding for future multi-spacecraft mission designs and for the coherence of CMEs.
