Successive Coronal Mass Ejections Associated with Weak Solar Energetic Particle Events
Explore the source record for details and available documents.
Bin Zhuang↗
SEARCH · Search NASA
Results for “Solar coronal mass ejections”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Interplanetary Coronal Mass Ejections in the Near-Earth Solar Wind During 1996-2002
We summarize the occurrence of interplanetary coronal mass injections (ICMEs) in the near-Earth solar wind during 1996-2002, corresponding to the increasing and maximum phases of solar cycle 23. In particular, we give a detailed list of such events. This list, based on in-situ observations, is not confined to subsets of ICMEs, such as magnetic clouds or those preceded by halo CMEs observed by the SOHO/LASCO coronagraph, and provides an overview of 214 ICMEs in the near-Earth solar wind during this period. The ICME rate increases by about an order of magnitude from solar minimum to solar maximum (when the rate is approximately 3 ICMEs/solar rotation period). The rate also shows a temporary reduction during 1999, and another brief, deeper reduction in late 2000-early 2001, which only approximately track variations in the solar 10 cm flux. In addition, there are occasional periods of several rotations duration when the ICME rate is enhanced in association with high solar activity levels. We find an indication of a periodic variation in the ICME rate, with a prominent period of approximately 165 days similar to that previously reported in various solar phenomena. It is found that the fraction of ICMEs that are magnetic clouds has a solar cycle variation, the fraction being larger near solar minimum. For the subset of events that we could associate with a CME at the Sun, the transit speeds from the Sun to the Earth were highest after solar maximum.
Cane, H. V.↗
The Integrated Science Investigation of the Sun (ISIS): Energetic Particle Measurements for the Solar Probe Plus Mission
One of the major goals of NASA's Solar Probe Plus (SPP) mission is to determine the mechanisms that accelerate and transport high-energy particles from the solar atmosphere out into the heliosphere. Processes such as coronal mass ejections and solar flares, which peak roughly every 11 years around solar maximum, release huge quantities of energized matter, magnetic fields and electromagnetic radiation into space. The high-energy particles, known as solar energetic particles or SEPs, present a serious radiation threat to human explorers living and working outside low-Earth orbit and to technological assets such as communications and scientific satellites in space. This talk describes the Integrated Science Investigation of the Sun (ISIS) - Energetic Particle Instrument suite. ISIS measures key properties such as intensities, energy spectra, composition, and angular distributions of the low-energy suprathermal source populations, as well as the more hazardous, higher energy particles ejected from the Sun. By making the first-ever direct measurements of the near-Sun regions where the acceleration takes place, ISIS will provide the critical measurements that, when integrated with other SPP instruments and with solar and interplanetary observations, will lead to a revolutionary new understanding of the Sun and major drivers of solar system space weather.
McComas, D. J.↗
The Fraction of Interplanetary Coronal Mass Ejections That Are Magnetic Clouds: Evidence for a Solar Cycle Variation
"Magnetic clouds" (MCs) are a subset of interplanetary coronal mass ejections (ICMEs) characterized by enhanced magnetic fields with an organized rotation in direction, and low plasma beta. Though intensely studied, MCs only constitute a fraction of all the ICMEs that are detected in the solar wind. A comprehensive survey of ICMEs in the near- Earth solar wind during the ascending, maximum and early declining phases of solar cycle 23 in 1996 - 2003 shows that the MC fraction varies with the phase of the solar cycle, from approximately 100% (though with low statistics) at solar minimum to approximately 15% at solar maximum. A similar trend is evident in near-Earth observations during solar cycles 20 - 21, while Helios 1/2 spacecraft observations at 0.3 - 1.0 AU show a weaker trend and larger MC fraction.
Richardson, I. G.↗
Source and Propagation of a Streamer Blowout Coronal Mass Ejection Observed by the Parker Solar Probe
In the first orbit of the Parker Solar Probe (PSP), in situ thermal plasma and magnetic field measurements were collected as close as 35RSun from the Sun, an environment that had not been previously explored. During the first orbit of PSP, the spacecraft flew through a streamer blowout coronal mass ejection (SBO-CME) on 2018 November 11 at 23:50 UT as it exited the science encounter. The SBO-CME on November 11 was directed away from the Earth and was not visible by L1 or Earth-based telescopes due to this geometric configuration. However, PSP and the STEREO-A spacecraft were able to make observations of this slow (v ≈ 380 kms−1) SBO-CME. Using the PSP data, STEREO-A images, and Wang–Sheeley–Arge model, the source region of the CME is found to be a helmet streamer formed between the northern polar coronal hole and a mid-latitude coronal hole. Using the YGUAZU-A model, the propagation of the CME is traced from the source at the Sun to PSP. This model predicts the travel time of the flux rope to the PSP spacecraft as 30 hr, which is within 0.33 hr of the actual measured arrival time. The in situ Solar Wind Electrons Alphas and Protons data were examined to determine that no shock was associated with this SBO-CME. Modeling of the SBO-CME shows that no shock was present at PSP; however, at other positions along the SBO-CME front, a shock could have formed. The geometry of the event requires in situ and remote sensing observations to characterize the SBO-CME and further understand its role in space weather.
Kelly Elizabeth Korreck↗
Coronal mass ejections and the injection profiles of solar energetic particle events
Previous studies using Skylab and Solwind coronagraph observations have shown that almost all E greater than 10 MeV solar energetic proton (SEP) events are associated with the occurrence of a coronal mass ejection (CME). These earlier studies did not address the relationship between the position of the associated CME and the timing of the injection of particles into the interplanetary medium. Ten cases are selected in which a SEP event observed with the GSFC detectors on the IMP 8 or ISEE 3 spacecraft was correlated to a CME well observed by the Solwind coronagraph. The height of the leading edge of the CME is compared with the particle injection profiles for several energy ranges using the solar release times for the particles. The derived injection profiles are found to be increasing and sometimes reaching maximum while the associated CMEs are at heights of 2-10 Ro.
Kahler, S. W.↗
The Relation between Coronal Holes and Coronal Mass Ejections during the Rise, Maximum, and Declining Phases of Solar Cycle 23
We study the interaction between coronal holes (CHs) and coronal mass ejections (CMEs) using a resultant force exerted by all the coronal holes present on the disk and is defined as the coronal hole influence parameter (CHIP). The CHIP magnitude for each CH depends on the CH area, the distance between the CH centroid and the eruption region, and the average magnetic field within the CH at the photospheric level. The CHIP direction for each CH points from the CH centroid to the eruption region. We focus on Solar Cycle 23 CMEs originating from the disk center of the Sun (central meridian distance ≤15deg) and resulting in magnetic clouds (MCs) and non-MCs in the solar wind. The CHIP is found to be the smallest during the rise phase for MCs and non-MCs. The maximum phase has the largest CHIP value (2.9 G) for non-MCs. The CHIP is the largest (5.8 G) for driverless (DL) shocks, which are shocks at 1 AU with no discernible MC or non-MC. These results suggest that the behavior of non-MCs is similar to that of the DL shocks and different from that of MCs. In other words, the CHs may deflect the CMEs away from the Sun-Earth line and force them to behave like limb CMEs with DL shocks. This finding supports the idea that all CMEs may be flux ropes if viewed from an appropriate vantage point.
CMEs↗
Large-scale Coronal Dimming Foreshadowing a Solar Eruption on 2011 October 1
Understanding large-scale solar eruptions requires detailed investigation of the entire system's evolution, including the magnetic environment enveloping the source region and searches for precursor activity prior to event onset. We combine stereoscopic observations from the Solar Dynamics Observatory (SDO) and STEREO-B spacecraft for several hours before a filament ejection, M1.2-class eruptive flare, and coronal mass ejection (CME) originating in NOAA active region (AR) 11305 on 2011 October 1. Two episodes of significant preeruption coronal dimming that occurred well to the southeast of the ejected filament are identified. The CME subsequently took off with a substantial component of velocity toward the dimming, which became very pronounced during eruption. We used SDO/Helioseismic and Magnetic Imager (HMI) data to reconstruct the magnetic environment of the system and found that it contains a null point near the dimming region. AR 11305 had quite complex connections to nearby ARs 11302 and 11306, as well as to other regions of decayed AR flux. The intensifying and spatially expanding precursor dimming was accompanied by southeastward rising motions of loops toward the null point and northeastward and southwestward motions of loops retracting away. These motions and the dimming are consistent with persistent magnetic reconnection occurring at the null point as it moved upward and southeastward, thereby removing a strapping magnetic field high above AR 11305. Eventually, the filament was ejected explosively toward the null point. We conclude that the breakout model for solar eruptions provides a compelling account of this event. Furthermore, we conjecture that preeruption dimmings may be much more frequent than currently recognized.
solar flares↗
Charge state composition in coronal hole and CME related solar wind: Latitudinal variations observed by Ulysses and WIND
Iron charge states in recurrent coronal hole-associated solar wind flows are obtained in the ecliptic by WIND/SMS, while measurements of iron and silicon from the polar coronal holes are available from Ulysses/SWICS. Ulysses/SWICS also provides ion composition of coronal mass ejection (CME)-related solar wind. Both coronal hole-associated and CME-related solar wind charge charges show heliographic latitudinal variations.
Galvin, A. B.↗
Height of Shock Formation in the Solar Corona Inferred from Observations of Type II Radio Bursts and Coronal Mass Ejections
Employing coronagraphic and EUV observations close to the solar surface made by the Solar Terrestrial Relations Observatory (STEREO) mission, we determined the heliocentric distance of coronal mass ejections (CMEs) at the starting time of associated metric type II bursts. We used the wave diameter and leading edge methods and measured the CME heights for a set of 32 metric type II bursts from solar cycle 24. We minimized the projection effects by making the measurements from a view that is roughly orthogonal to the direction of the ejection. We also chose image frames close to the onset times of the type II bursts, so no extrapolation was necessary. We found that the CMEs were located in the heliocentric distance range from 1.20 to 1.93 solar radii (Rs), with mean and median values of 1.43 and 1.38 Rs, respectively. We conclusively find that the shock formation can occur at heights substantially below 1.5 Rs. In a few cases, the CME height at type II onset was close to 2 Rs. In these cases, the starting frequency of the type II bursts was very low, in the range 25-40 MHz, which confirms that the shock can also form at larger heights. The starting frequencies of metric type II bursts have a weak correlation with the measured CME/shock heights and are consistent with the rapid decline of density with height in the inner corona.
EUV↗
A forward-reverse shock pair in the solar wind driven by over-expanison of a coronal mass ejection: Ulysses observations
A previously unidentified type of solar wind forward-reverse shock pair has been observed by Ulysses at 4.64 AU and S32.5 deg. In contrast to most solar wind forward-reverse shock pairs, which are driven by the speed difference between fast solar wind plasma and slower plasma ahead, this particular shock pair was driven purely by the over-expansion of a coronal mass ejection (CME) in transit from the Sun. A simple numerical simulation indicates that the over-expansion was a result of a high initial internal plasma and magnetic field pressure within the CME. The CME observed at 4.64 AU had the internal field structure of a magnetic flux rope. This event was associated with a solar disturbance in which new magnetic loops formed in the corona almost directly beneath Ulysses approximately 11 days earlier. This association suggests that the flux rope was created as a result of reconnection between the 'legs' of neighboring magnetic loops within the rising CME.
Gosling, J. T.↗
Journey 'Round the Sun: STEREO Science and Spacecraft Performance Results
The Solar TErrestrial RElations Observatory (STEREO) was originally designed as a two to five year heliocentric orbit mission to study coronal mass ejections (CMEs), solar energetic particles (SEPs), and the solar wind. After over ten years of continuous science data collection, the twin NASA STEREO observatories have significantly advanced the understanding of Heliophysics. This mission was the first to image CMEs all the way from the Sun to Earth and to observe the entire sphere of the Sun at one time. STEREO has demonstrated the importance of a point of view beyond the Sun-Earth line to significantly improve CME arrival time estimates and in understanding CME structure and trajectories and the longitudinal distribution of SEPs. STEREO was also the first to use one launch vehicle to insert two spacecraft into opposing heliocentric orbits, undergo a 3.5 month long superior solar conjunction, implement unattended daily science operations on two deep space observatories, maintain 7 arcsec continuous pointing without gyros, and detect and attempt to recover a spacecraft after a 22-month long communications anomaly at a range of 2 AU. This paper discusses the significant performance results after the first ten years of operations of the STEREO mission from its journey around the Sun.
Ossing, Daniel A.↗
Solar Storms and Flying to Mars
Explore the source record for details and available documents.
Space Weather↗
Deflections of Fast Coronal Mass Ejections and the Properties of Associated Solar Energetic Particle Events
The onset times and peak intensities of solar energetic particle (SEP) events at Earth have long been thought to be influenced by the open magnetic fields of coronal holes (CHs). The original idea was that a CH lying between the solar SEP source region and the magnetic footpoint of the 1 AU observer would result in a delay in onset and/or a decrease in the peak intensity of that SEP event. Recently, Gopalswamy et al. showed that CHs near coronal mass ejection (CME) source regions can deflect fast CMEs from their expected trajectories in space, explaining the appearance of driverless shocks at 1 AU from CMEs ejected near solar central meridian (CM). This suggests that SEP events originating in CME-driven shocks may show variations attributable to CH deflections of the CME trajectories. Here, we use a CH magnetic force parameter to examine possible effects of CHs on the timing and intensities of 41 observed gradual E approx 20 MeV SEP events with CME source regions within 20 deg. of CM. We find no systematic CH effects on SEP event intensity profiles. Furthermore, we find no correlation between the CME leading-edge measured position angles and SEP event properties, suggesting that the widths of CME-driven shock sources of the SEPs are much larger than the CMEs. Independently of the SEP event properties, we do find evidence for significant CME deflections by CH fields in these events
coronal mass ejections (CMEs)↗
Journey 'Round the Sun: STEREO Science and Spacecraft Performance Results
The Solar TErrestrial RElations Observatory (STEREO) was originally designed as a two- to five-year heliocentric orbit mission to study coronal mass ejections (CMEs), solar energetic particles (SEPs), and the solar wind. After over ten years of continuous science data collection, the twin NASA STEREO observatories have significantly advanced the understanding of Heliophysics. This mission was the first to image CMEs all the way from the Sun to Earth and to observe the entire sphere of the Sun at one time. STEREO has demonstrated the importance of a point of view beyond the Sun-Earth line to significantly improve CME arrival time estimates and in understanding CME structure and trajectories and the longitudinal distribution of SEPs. STEREO was also the first to use one launch vehicle to insert two spacecraft into opposing heliocentric orbits, undergo a 3.5-month-long superior solar conjunction, implement unattended daily science operations on two deep space observatories, maintain 7 arcsec continuous pointing without gyros, and detect and attempt to recover a spacecraft after a 22-month long communications anomaly at a range of 2 AU (Astronomical Units). This paper discusses the significant performance results after the first ten years of operations of the STEREO mission from its journey around the Sun.
Ossing, Daniel A.↗
Database of Episode-Integrated Solar Energetic Proton Fluences
A new database of proton episode-integrated fluences is described. This database contains data from two different instruments on multiple satellites. The data are from instruments on the Interplanetary Monitoring Platform-8 (IMP8) and the Geostationary Operational Environmental Satellites (GOES) series. A method to normalize one set of data to one another is presented to create a seamless database spanning 1973 to 2016. A discussion of some of the characteristics that episodes exhibit is presented, including episode duration and number of peaks. As an example of what can be understood about episodes, the July 4, 2012 episode is examined in detail. The coronal mass ejections and solar flares that caused many of the fluctuations of the proton flux seen at Earth are associated with peaks in the proton flux during this episode. The reasoning for each choice is laid out to provide a reference for how CME and solar flares associations are made.
episode characteristcs↗
Global Energetics of Large Solar Eruptive Events
We have evaluated the energetics of the larger solar eruptive events recorded with a variety of spacecraft instruments between February 2002 and December 2006. All of the energetically important components of the flares and of the accompanying coronal mass ejections and solar energetic particles have been evaluated as accurately as the observations allow. These components include the following : (1) the total energy in the high temperature plasma determined from the RHESSI thermal X-ray observations; (2) the total energies in accelerated electrons above 20 keV and ions above 1 MeV from RHESSI hard X-ray and gamma-ray observations, respectively; (3) the potential and kinetic energies of the CME from SOHO/LASCO observations; (4) the solar energetic particle (SEP) energy estimates from in situ measurements on ACE, GOES, and SOHO; (5) the total radiated energy from the SORCEITSI measurements where available, and otherwise from the Flare Irradiance Spectral Model (FISM). The results are assimilated and discussed relative to the probable amount of non potential magnetic energy estimated to be available in the flaring active regions from MDI line-of-sight magnetograms.
Dennis, Brian R.↗
Inner Magnetospheric Physics
The inner magnetosphere extends from just above the topside ionosphere to approximately 8 RE geocentric distance. Magnetospheric physics is a young science that only started to be recognized as a region with the space observations by Explorer 1 in 1958. The region is mostly populated by ionized gas or plasma from Earth’s ionosphere. Plasma populations are differentiated by their energies primarily. From the least energetic to most are the plasmasphere, ring current, and radiation belts, extending from about 1 eV to 10 MeV in energy and from 1,000s cm-3 down to a few particles per cubic centimeter and less, respectively. The solar wind and solar erupted coronal mass ejections (CMEs) arriving and interacting with Earth’s magnetic field creates a dynamo effect that drives million ampere currents along magnetic field lines that close through the ionosphere. The solar wind dynamo also creates a 100s kV electric field across the magnetosphere that drives convective motion of the plasma within it. The solar wind driven currents compress Earth’s magnetic field on the sunward side and greatly extents the field on the nightside to form the magnetotail. The energy stored in the magnetotail is impulsively released when magnetic field lines there merge, releasing energy into the plasma trapped by the magnetic field. Those plasma become the ring current that loses plasma into the atmosphere to produce the aurora and at the same time ring current plasma can be further energized by wave-particle interactions to become the radiation belts. The presentation will review these topics and a few of the underlying physical processes that are involved in this highly coupled planetary system.
inner magnetosphere↗