Slow Coronal Mass Ejections Research Articles

The Analysis of Interplanetary Shocks Associated with Six Major Geo-Effective Coronal Mass Ejections during Solar Cycle 24

A Coronal Mass Ejection (CME) is an ejection of energetic plasma with magnetic field from the Sun. In traversing the Sun-Earth distance, the kinematics of the CME is immensely important for the prediction of space weather. The objective of the present work is to study the propagation properties of six major geo-effective CMEs and their associated interplanetary shocks which were observed during solar cycle 24. These reported CME events produced intense geo-magnetic storms (Dst > 140 nT). The six CME events have a broad range of initial linear speeds ~600 - 2700 km/sec in the LASCO/SOHO field of view, comparing two slow CMEs (speed ~579 km/sec and 719 km/sec), three moderate speed CMEs (speed ~1366, 1571, 1008 km/sec), and one fast CME (speed ~2684 km/sec). The actual arrival time of the reported events is compared with the arrival time calculated using the Empirical Shock Arrival model (ESA model). For acceleration estimation, we utilize three different acceleration-speed equations reported in the previous literatures for different acceleration cessation distance (ACD). In addition, we compared the transit time estimated using the second-order speed of CMEs with observed transit time. We also compared the observed transit time with transit time obtained from various shock arrival model. From our present study, we found the importance of acceleration cessation distance for CME propagation in interplanetary space and better acceleration speed for transit time calculation than other equations for CME forecasting.

Comparison of Features of the Generation of Coronal Mass Ejections with Variable Velocity in the Field of View of LASCO Coronagraphs

This paper compares features of the generation of coronal mass ejections (CMEs) with the lowest, intermediate, and highest velocities in the field of view of LASCO C2 and C3 coronagraphs found from an analysis of multi-wavelength data with high temporal and spatial resolution. The dynamics of the field characteristics in the umbra of sunspots of active regions (ARs) in which variable-velocity CMEs occur are compared based on SDO/HMI vector magnetic field measurements. It is found that there are almost no noticeable changes in field characteristics in the AR sunspots in which slow CMEs occur after the onset of the eruptive event. However, there are noticeable changes in the field intensity and inclination angles of the flux tube emerging from the umbra of the sunspot in some AR sunspots in which CMEs occur after the onset of the eruptive event. Thus, for the fast CME detected on January 7, 2014, the inclination angle of the flux tube from the umbra of one of the sunspots before the flare onset reached a maximum value of ≈4°. After the flare onset, it was less than 1°.

Analysis of Forbush decreases observed using a muon telescope in Antarctica starting on 21 June 2015**Supported by NSFC (11575204)

A cosmic-ray muon telescope has been collecting data since the end of 2014, which was shortly after the telescope was built in the Zhongshan Station of Antarctica. The telescope is the first observation device to be built by Chinese scientists in Antarctica. The pressure change is very strong in Zhongshan station. The count rate of the pressure correction results shows that the large variations in the count rate are likely caused by pressure fluctuations. During the period from 18 June to 22 June 2015, four halo coronal mass ejections (CMEs) were ejected from the Sun. These CMEs initiated a series of Forbush decreases (FD) when they reached the Earth. We conducted a comprehensive study of the intensity fluctuations of galactic cosmic rays recorded during FDs. The intensity fluctuations used in this study were collected by cosmic ray detectors of multiple stations (Zhongshan, McMurdo, South Polar, and Nagoya), and the solar wind measurements were collected by ACE and WIND. The profile of the FD of 22 June demonstrated a four-step decrease. The traditional one- or two-step FD classification method does not adequately explain the FD profile results. The interaction between the faster CME that occurred on 21 June 2015 and the two slow CMEs of the earlier few days should be considered. The cosmic ray intensities of the South Pole, McMurdo, and Zhongshan stations have similar hourly variations, whereas the galactic cosmic rays recorded between polar and non-polar locations are distinct. The FD pre-increase of 22 June 2015 for the Nagoya muon telescope (non-polar location) lags those of the McMurdo and Zhongshan stations (polar locations) by 1 h. The FD onset of 22 June 2015 for the Nagoya muon telescope lags those of the polar locations by 1 h.

Numerical study of the cascading energy conversion of the reconnection current sheet in solar eruptions

Magnetic reconnection plays an important role in the energy conversion during solar eruptions. In this work, we present a resistive magnetohydrodynamical study (2.5D) of a flux rope eruption based on the Lin and Forbes model regarding cascading reconnection. We use a second-order Godunov scheme code, to better understand the physical mechanisms responsible for high reconnection rates and the internal structure, particularly in chaotic or turbulent regions, of the coronal mass ejection (CME)/flare current sheet (CS). Two sets of simulations with Lundquist numbers of 1.18 x 10(5) and 2.35 x 10(5) in the vicinity of the CS, generating a slow CME and a moderate one, show global dynamic features largely consistent with the flare model. Looking into the fine structure of the CS, magnetic reconnection employs simultaneously the Sweet-Parker mode and time-dependent small-scale Petschek patterns in the early stage. As the flux rope rises, the outflow region becomes turbulent, which further enhances the reconnection rates. Our results show that coalescence and fusion processes of plasmoids provide a large number of small, transient local diffusion regions to dissipate magnetic energy, and confirm that the dissipation starts at macro-MHD scales rather than ion inertial lengths. The two runs have the same range of the local reconnection rates (10(-4)-0.3) relevant to CMEs. The fast rates are closely proportional to the square of the aspect ratio of multiple small-scale CSs. The topology of the magnetic field and the turbulence spectrum of the energy cascade are statistically addressed as well.

A Major Geoeffective CME from NOAA 12371: Initiation, CME–CME Interactions, and Interplanetary Consequences

In this article, we present a multi-wavelength and multi-instrument investigation of a halo coronal mass ejection (CME) from active region NOAA 12371 on 21 June 2015 that led to a major geomagnetic storm of minimum $\mathrm{Dst} = -204$ nT. The observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory in the hot EUV channel of 94 A confirm the CME to be associated with a coronal sigmoid that displayed an intense emission ( $T \sim6$ MK) from its core before the onset of the eruption. Multi-wavelength observations of the source active region suggest tether-cutting reconnection to be the primary triggering mechanism of the flux rope eruption. Interestingly, the flux rope eruption exhibited a two-phase evolution during which the “standard” large-scale flare reconnection process originated two composite M-class flares. The eruption of the flux rope is followed by the coronagraphic observation of a fast, halo CME with linear projected speed of 1366 km s−1. The dynamic radio spectrum in the decameter-hectometer frequency range reveals multiple continuum-like enhancements in type II radio emission which imply the interaction of the CME with other preceding slow speed CMEs in the corona within $\approx10$ – $90~\mbox{R} _{\odot}$ . The scenario of CME–CME interaction in the corona and interplanetary medium is further confirmed by the height–time plots of the CMEs occurring during 19 – 21 June. In situ measurements of solar wind magnetic field and plasma parameters at 1 AU exhibit two distinct magnetic clouds, separated by a magnetic hole. Synthesis of near-Sun observations, interplanetary radio emissions, and in situ measurements at 1 AU reveal complex processes of CME–CME interactions right from the source active region to the corona and interplanetary medium that have played a crucial role towards the large enhancement of the geoeffectiveness of the halo CME on 21 June 2015.

Nowcasting of Solar Energetic Particle Events using near real-time Coronal Mass Ejection characteristics in the framework of the FORSPEF tool

In this work the derived occurrence probability of solar energetic particle (SEP) events (i.e. proton events measured at Earth’s position) and their peak fluxes and total fluences depending on coronal mass ejection (CME) parameters, i.e. linear speed (V) and the angular width (AW) are presented. A new SEP catalogue with associated CME data from 1997 to 2013 is utilized. It is found that the SEP probability strongly depends on the CME speed and the angular width as follows: The highest association (72.70%) is obtained for the full halo CMEs with V ≥ 1500 km s−1 and the lowest association (0.7%) is found for the non halo CMEs with 400 km s−1 ≤ V ≤ 1000 km s−1. The SEP occurrence probabilities are different as much as 26 times according to the CME speed (V), comparing fast versus slow CMEs and 44 times according to the AW, comparing halo to non halo CMEs. Furthermore, linear regressions of the proton peak flux and integral fluence at several integral energy channels (E > 10 MeV, E > 30 MeV, E > 60 MeV, E > 100 MeV) were obtained. Our results, were used to build a module of an operational forecasting tool (i.e. FORecasting Solar Particle Events and Flares – FORSPEF, http://tromos.space.noa.gr/forspef/). This module performs nowcasting (short term forecasting) of SEP events using near real-time CME identifications obtained from CACTus (http://sidc.oma.be/cactus/). The outputs offered by the operational module of the tool to the end user (textural, pictorial, archived data) are presented. Finally, the validation of the system, in terms of archived data is described, in terms of categorical scores (Probability of Detection – POD and a False Alarm Rate – FAR).

Detailed analysis of dynamic evolution of three Active Regions at the photospheric level before flare and CME occurrence

We present a combined analysis of the applications of the weighted horizontal magnetic gradient (denoted as WGM in Korsós et al. (2015)) method and the magnetic helicity tool (Berger and Field, 1984) employed for three active regions (ARs), namely NOAA AR 11261, AR 11283 and AR 11429. We analysed the time series of photospheric data from the Solar Dynamics Observatory taken between August 2011 and March 2012. During this period the three ARs produced a series of flares (eight M- and six X-class) and coronal mass ejections (CMEs). AR 11261 had four M-class flares and one of them was accompanied by a fast CME. AR 11283 had similar activities with two M- and two X-class flares, but only with a slow CME. Finally, AR 11429 was the most powerful of the three ARs as it hosted five compact and large solar flare and CME eruptions. For applying the WGM method we employed the Debrecen sunspot data catalogue, and, for estimating the magnetic helicity at photospheric level we used the Space-weather HMI Active Region Patches (SHARP’s) vector magnetograms from SDO/HMI (Solar Dynamics Observatory/Helioseismic and Magnetic Imager). We followed the evolution of the components of the WGM and the magnetic helicity before the flare and CME occurrences. We found a unique and mutually shared behaviour, called the U-shaped pattern, of the weighted distance component of WGM and of the shearing component of the helicity flux before the flare and CME eruptions. This common pattern is associated with the decreasing-receding phases yet reported only known to be a necessary feature prior to solar flare eruption(s) but found now at the same time in the evolution of the shearing helicity flux. This result leads to the conclusions that (i) the shearing motion of photospheric magnetic field may be a key driver for solar eruption in addition to the flux emerging process, and that (ii) the found decreasing-approaching pattern in the evolution of shearing helicity flux may be another precursor indicator for improving the forecasting of solar eruptions.

CME Dynamics Using STEREO and LASCO Observations: The Relative Importance of Lorentz Forces and Solar Wind Drag

We seek to quantify the relative contributions of Lorentz forces and aerodynamic drag on the propagation of solar coronal mass ejections (CMEs). We use Graduated Cylindrical Shell (GCS) model fits to a representative set of 38 CMEs observed with the SOHO and STEREO spacecraft. We find that the Lorentz forces generally peak between 1.65 and 2.45 Rsun for all CMEs. For fast CMEs, Lorentz forces become negligible in comparison to aerodynamic drag as early as 3.5--4 Rsun. For slow CMEs, however, they become negligible only by 12--50 Rsun. For these slow events, our results suggest that some of the magnetic flux might be expended in CME expansion or heating. In other words, not all of it contributes to directed propagation. Our results are expected to be important in building a physical model for understanding the Sun-Earth dynamics of CMEs.

Solar flare associated coronal mass ejections causing geo-effectiveness and Forbush decreases

In the present study, we have selected 35 halo Coronal Mass Ejections (CMEs) associated with solar flares, Geomagnetic Storms (GSs) and Forbush decrease (Fd) chosen from 1st January 2000 to 31st December 2007 (i.e., the descending phase of solar cycle 23) observed by the Large Angle Spectrometric Coronagraph (LASCO) on board the SOHO spacecraft. Statistical analyses are performed to look at the distribution of solar flares associated with halo CMEs causing GSs and Fd and investigated the relationship between solar flare and halo CME parameters with GSs and Fd. Forbush decrease is the phenomenon of rapid decrease in cosmic ray intensity following the CME. Our analysis indicates that during 2000 to 2007 the northern region produced 44 % of solar flares associated with halo CMEs, GSs, and Fd, whereas 56 % solar flares associated with halo CMEs, GSs, and Fd were produced in the southern region. The northern and the southern hemispheres between 10° to 20° latitudinal belts are found to be more effective in producing events leading to Fd. From our selected events, we found that about 60 % of super-intense storms (\(\mbox{Dst} \leq -200~\mbox{nT}\)) caused by halo CMEs are associated with X-class flares. Fast halo CMEs associated with X-class flares originating from 0° to 25° latitudes are better potential candidates in producing super-intense GSs than the slow halo CMEs associated with other classes of flares.

A model for stealth coronal mass ejections

AbstractStealth coronal mass ejections (CMEs) are events in which there are almost no observable signatures of the CME eruption in the low corona but often a well‐resolved slow flux rope CME observed in the coronagraph data. We present results from a three‐dimensional numerical magnetohydrodynamics (MHD) simulation of the 1–2 June 2008 slow streamer blowout CME that Robbrecht et al. (2009) called “the CME from nowhere.” We model the global coronal structure using a 1.4 MK isothermal solar wind and a low‐order potential field source surface representation of the Carrington Rotation 2070 magnetogram synoptic map. The bipolar streamer belt arcade is energized by simple shearing flows applied in the vicinity of the helmet streamer's polarity inversion line. The flows are large scale and impart a shear typical of that expected from the differential rotation. The slow expansion of the energized helmet streamer arcade results in the formation of a radial current sheet. The subsequent onset of expansion‐induced flare reconnection initiates the stealth CME while gradually releasing the stored magnetic energy. We present favorable comparisons between our simulation results and the multiviewpoint SOHO‐LASCO (Large Angle and Spectrometric Coronagraph) and STEREO‐SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) coronagraph observations of the preeruption streamer structure and the initiation and evolution of the stealth streamer blowout CME.

REDEFINING THE BOUNDARIES OF INTERPLANETARY CORONAL MASS EJECTIONS FROM OBSERVATIONS AT THE ECLIPTIC PLANE

ABSTRACT On 2015 January 6–7, an interplanetary coronal mass ejection (ICME) was observed at L1. This event, which can be associated with a weak and slow coronal mass ejection, allows us to discuss the differences between the boundaries of the magnetic cloud and the compositional boundaries. A fast stream from a solar coronal hole surrounding this ICME offers a unique opportunity to check the boundaries’ process definition and to explain differences between them. Using Wind and ACE data, we perform a complementary analysis involving compositional, magnetic, and kinematic observations providing relevant information regarding the evolution of the ICME as travelling away from the Sun. We propose erosion, at least at the front boundary of the ICME, as the main reason for the difference between the boundaries, and compositional signatures as the most precise diagnostic tool for the boundaries of ICMEs.

A DECAMETER STATIONARY TYPE IV BURST IN IMAGING OBSERVATIONS ON 2014 SEPTEMBER 6

ABSTRACT First-of-its-kind radio imaging of a decameter solar stationary type IV radio burst has been presented in this paper. On 2014 September 6 the observations of type IV burst radio emission were carried out with the two-dimensional heliograph based on the Ukrainian T-shaped radio telescope (UTR-2), together with other telescope arrays. Starting at ∼09:55 UT and for ∼3 hr, the radio emission was kept within the observational session of UTR-2. The interesting observation covered the full evolution of this burst, “from birth to death.” During the event lifetime, two C-class solar X-ray flares with peak times 11:29 UT and 12:24 UT took place. The time profile of this burst in radio has a double-humped shape that can be explained by injection of energetic electrons, accelerated by the two flares, into the burst source. According to the heliographic observations, we suggest that the burst source was confined within a high coronal loop, which was part of a relatively slow coronal mass ejection. The latter has been developed for several hours before the onset of the event. Through analysis of about 1.5 × 106 heliograms (3700 temporal frames with 4096 images in each frame that correspond to the number of frequency channels), the radio burst source imaging shows a fascinating dynamical evolution. Both space-based (GOES, SDO, SOHO, STEREO) data and various ground-based instrumentation (ORFEES, NDA, RSTO, NRH) records have been used for this study.

An Intense Flare–CME Event in 2015: Propagation and Interaction Effects Between the Sun and Earth’s Orbit

In this paper, We report the interplanetary effects of a fast coronal mass ejection (CME) associated with the intense X2.7 flare that occurred on 05 May 2015. The near-Sun signatures of the CME at low-coronal heights $<$2 {R$_{\odot}$} are obtained from the EUV images at 171 {\AA} and metric radio observations. The intensity and duration of the CME-driven radio bursts in the near-Sun and interplanetary medium indicate this CME event to be an energetic one. The interplanetary scintillation data, along with the low-frequency radio spectrum, played a crucial role in understanding the radial evolution of the speed and expansion of the CME in the inner heliosphere as well as its interaction with a preceding slow CME. The estimation of the speed of the CME at several points along the Sun to 1 AU shows shows that i) the CME went through a rapid acceleration as well as expansion up to a height of $\approx$6 {R$_{\odot}$}, and ii) the CME continued to propagate at speed $\geq$800 kms$^{-1}$ between the Sun and 1 AU. These results show that the CME likely overcame the drag exerted by the ambient/background solar-wind with the support of its internal magnetic energy. When the CME interacted with a slow preceding CME, the turbulence level associated with the CME-driven disturbance increased significantly.

Numerical simulation of multiple CME‐driven shocks in the month of 2011 September

AbstractA global, three‐dimensional (3‐D) numerical simulation model has been employed to study the Sun‐to‐Earth propagation of multiple (12) coronal mass ejections (CMEs) and their associated shocks in September 2011. The inputs to the simulation are based on actual solar observations, which include the CME speeds, source locations, and photospheric magnetic fields. The simulation result is fine tuned with in situ solar wind data observations at 1 AU by matching the arrival time of CME‐driven shocks. During this period three CME‐driven interplanetary (IP) shocks induced three sizable geomagnetic storms on 9, 17, and 26 September, with Dst values reaching −69, −70, and −101 nT, respectively. These storm events signify the commencement of geomagnetic activity in the solar cycle 24. The CME propagation speed near the Sun (e.g., &lt; 30 RS) has been widely used to estimate the interplanetary CME (ICME)/Shock arrival time at 1 AU. Our simulation indicates that the background solar wind speed, as expected, is an important controlling parameter in the propagation of IP shocks and CMEs. Prediction of the ICME/shock arrival time at 1 AU can be more problematic for slow (e.g., &lt; 500 km s−1) than fast CMEs (&gt;1000 km s−1). This is because the effect of the background solar wind is more pronounced for slow CMEs. Here we demonstrate this difficulty with a slow (400 km s−1) CME event that arrived at the Earth in 3 days instead of the predicted 4.3 days. Our results also demonstrate that a long period (a month in this case) of simulation may be necessary to make meaningful solar source geomagnetic storm associations.

ON SUN-TO-EARTH PROPAGATION OF CORONAL MASS EJECTIONS: II. SLOW EVENTS AND COMPARISON WITH OTHERS

ABSTRACT As a follow-up study on Sun-to-Earth propagation of fast coronal mass ejections (CMEs), we examine the Sun-to-Earth characteristics of slow CMEs combining heliospheric imaging and in situ observations. Three events of particular interest, the 2010 June 16, 2011 March 25, and 2012 September 25 CMEs, are selected for this study. We compare slow CMEs with fast and intermediate-speed events, and obtain key results complementing the attempt of Liu et al. to create a general picture of CME Sun-to-Earth propagation: (1) the Sun-to-Earth propagation of a typical slow CME can be approximately described by two phases, a gradual acceleration out to about 20–30 solar radii, followed by a nearly invariant speed around the average solar wind level; (2) comparison between different types of CMEs indicates that faster CMEs tend to accelerate and decelerate more rapidly and have shorter cessation distances for the acceleration and deceleration; (3) both intermediate-speed and slow CMEs would have speeds comparable to the average solar wind level before reaching 1 au; (4) slow CMEs have a high potential to interact with other solar wind structures in the Sun–Earth space due to their slow motion, providing critical ingredients to enhance space weather; and (5) the slow CMEs studied here lack strong magnetic fields at the Earth but tend to preserve a flux-rope structure with an axis generally perpendicular to the radial direction from the Sun. We also suggest a “best” strategy for the application of a triangulation concept in determining CME Sun-to-Earth kinematics, which helps to clarify confusions about CME geometry assumptions in the triangulation and to improve CME analysis and observations.

SPECTRAL PROPERTIES OF LARGE GRADUAL SOLAR ENERGETIC PARTICLE EVENTS. I. FE, O, AND SEED MATERIAL

ABSTRACT We have surveyed ∼0.1–100 MeV nucleon−1 O and Fe fluence spectra during 46 isolated, large gradual SEP events observed at ACE during solar cycles 23 and 24. Most SEP spectra are well represented by the four-parameter Band function with a normalization constant, low-energy spectral slope, high-energy spectral slope, and break energy. The O and Fe spectral slopes are similar and most spectra steepen above the break energy, probably due to common acceleration and transport processes affecting different ion species. SEP spectra above the break energies depend on the origin of the seed population; larger contributions of suprathermal flare material result in higher Fe/O ratios and flatter spectra at higher energies. SEP events with steeper O spectra at low energies and higher break energies are associated with slower coronal mass ejections (CMEs), while those associated with fast (&gt;2000 km s−1) CMEs and ground level enhancements have harder or flatter spectra at low and high energies, and O break energies between ∼1 and 10 MeV nucleon−1. The latter events are enriched in 3He and higher-energy Fe, and have Fe spectra that rollover at significantly lower energies compared with O, probably because Fe ions with smaller Q/M ratios can escape from the distant shock more easily than O ions with larger Q/M ratios. We conclude that SEP spectral properties result from many complex and competing effects, namely Q/M-dependent scattering, shock properties, and the origin of the seed populations, all of which must be taken into account to develop a comprehensive picture of CME-driven shock acceleration of large gradual SEP events.

CME PROPAGATION: WHERE DOES AERODYNAMIC DRAG “TAKE OVER”?

We investigate the Sun-Earth dynamics of a set of eight well observed solar coronal mass ejections (CMEs) using data from the STEREO spacecraft. We seek to quantify the extent to which momentum coupling between these CMEs and the ambient solar wind (i.e., the aerodynamic drag) influences their dynamics. To this end, we use results from a 3D flux rope model fit to the CME data. We find that solar wind aerodynamic drag adequately accounts for the dynamics of the fastest CME in our sample. For the relatively slower CMEs, we find that drag-based models initiated below heliocentric distances ranging from 15 to 50 $R_{\odot}$ cannot account for the observed CME trajectories. This is at variance with the general perception that the dynamics of slow CMEs are influenced primarily by solar wind drag from a few $R_{\odot}$ onwards. Several slow CMEs propagate at roughly constant speeds above 15--50 $R_{\odot}$. Drag-based models initiated above these heights therefore require negligible aerodynamic drag to explain their observed trajectories.

Extreme geomagnetic disturbances due to shocks within CMEs

AbstractWe report on features of solar wind‐magnetosphere coupling elicited by shocks propagating through coronal mass ejections (CMEs) by analyzing the intense geomagnetic storm of 6 August 1998. During this event, the dynamic pressure enhancement at the shock combined with a simultaneous increase in the southward component of the magnetic field resulted in a large earthward retreat of Earth's magnetopause, which remained close to geosynchronous orbit for more than 4 h. This occurred despite the fact that both shock and CME were weak and relatively slow. Another similar example of a weak shock inside a slow CME resulting in an intense geomagnetic storm is the 30 September 2012 event, which strongly depleted the outer radiation belt. We discuss the potential of shocks inside CMEs to cause large geomagnetic effects at Earth, including magnetopause shadowing.

RADIAL FLOW PATTERN OF A SLOW CORONAL MASS EJECTION

Height–time plots of the leading edge of coronal mass ejections (CMEs) have often been used to study CME kinematics. We propose a new method to analyze the CME kinematics in more detail by determining the radial mass transport process throughout the entire CME. Thus, our method is able to estimate not only the speed of the CME front but also the radial flow speed inside the CME. We have applied this method to a slow CME with an average leading edge speed of about 480 km s−1. In the Lagrangian frame, the speeds of the individual CME mass elements stay almost constant within 2 and 15 RS, the range over which we analyzed the CME. Hence, we have no evidence of net radial forces acting on parts of the CME in this range or of a pile up of mass ahead of the CME. We find evidence that the leading edge trajectory obtained by tie-pointing may gradually lag behind the Lagrangian front-side trajectories derived from our analysis. Our results also allow a much more precise estimate of the CME energy. Compared with conventional estimates using the CME total mass and leading edge motion, we find that the latter may overestimate the kinetic energy and the gravitational potential energy.

The Properties of Solar Energetic Particle Event-Associated Coronal Mass Ejections Reported in Different CME Catalogs

We compare estimates of the speed and width of coronal mass ejections (CMEs) in several catalogs for the CMEs associated with ~200 solar energetic particle (SEP) events in 2006-2013 that included 25 MeV protons. The catalogs used are: CDAW, CACTUS, SEEDS and CORIMP, all derived from observations by the LASCO coronagraphs on the SOHO spacecraft, the CACTUS catalog derived from the COR2 coronagraphs on the STEREO-A and -B spacecraft, and the DONKI catalog, which uses observations from SOHO and the STEREO spacecraft. We illustrate how, for this set of events, CME parameters can differ considerably in each catalog. The well-known correlation between CME speed and proton event intensity is shown to be similar for most catalogs, but this is largely because it is determined by a few large particle events associated with fast CMEs, and small events associated with slow CMEs. Intermediate particle events "shuffle" in position when speeds from different catalogs are used. Quadrature spacecraft CME speeds do not improve the correlation. CME widths also vary widely between catalogs, and are influenced by plane of the sky projection and how the width is inferred from the coronagraph images. The high degree of association (~50%) between the 25 MeV proton events and "full halo" (360 deg.-width) CMEs as defined in the CDAW catalog is removed when other catalogs are considered. Using CME parameters from the quadrature spacecraft, the SEP intensity is correlated with CME width, which is also correlated with CME speed.