Coronal mass ejections (CME)

On September 1, 1859, Richard Carrington and Richard Hodgson were observing sunspots at noon when they saw a blinding arc grow between the dark spots, the first observed solar flare. Late that night, a massive disturbance was recorded in Earth’s magnetic field, and brilliant aurorae, bright enough to read by, lit up the sky even in equatorial countries such as Colombia. Decades later, the missing link between solar flares and magnetic storms on Earth became clear: coronal mass ejections (CMEs), eruptions of magnetized plasma from the outer solar atmosphere. White light from the Sun scatters o ff of CMEs, making them visible during eclipses and with solar coronagraphs. The discovery of CMEs in white light occurred in the early 1970s with the solar coronagraph on Skylab (MacQueen et al. 1974). Prior to this, radio spectroscopic observations had found evidence of sources propagating outward through the solar corona at speeds of thousands of km / s (solar Type II radio bursts, Wild et al. 1954) and the Culgoora radioheliograph had imaged coronal radio sources moving away from the Sun at comparable speeds (Figure 1.1, Riddle 1970). These observations came together into a coherent picture when solar type II radio bursts were found to be associated with the shock fronts formed by fast-moving coronal mass ejections (Gosling et al. 1976). These radio bursts are a means of detecting CMEs, signposts of the magnetic interaction between the Sun and Earth. 1.1 Impact of stellar activity on stellar evolution and planetary habitability Solar flares and CMEs often occur together, especially for the most energetic events. The probability that a solar flare has an associated CME increases with the flare’s intensity and duration, reaching 100% for the most energetic flares (Harrison 1995; Yashiro & Gopalswamy 2009). Magnetically active stars flare regularly with energy greater than the most energetic observed solar flare (10 32 ergs in blue and UV light, Scalo et al. 2007), suggesting that they may also have a high rate of CMEs. Drake et al. (2013) and Osten & Wolk (2015) extend the observed solar flare-CME asso- ciation rate to predict the CME mass loss rate of active stars, finding that it implies astronomical mass loss rates for active M dwarfs of 10 −11 M /yr (1000 times the

Our study demonstrates the periodic variation of the instantaneous projected radial speed of halo coronal mass ejections. In the lower solar corona, long-period oscillations, with the periods similar to discussed in this Letter, are often detected in prominences (e.g. Bi et al. 2014; Foullon et al. 2009). The oscillations are detected to be either excited by impulsive energy releases (e.g. Hershaw et al. 2011), or result from some over-stabilities processes (e.g. Tripathi et al. 2009). It is not clear whether the HCME oscillations belong to the same class of phenomena. At the coronagraph heights similar oscillations of the radial speed of CMEs have been detected by Krall et al. (2001) and Shanmugaraju et al. (2010). The HCME oscillations discussed here differ from them as we detect the oscillatory motion in the plane perpendicular to the direction of the CME motion. However, if this oscillation is observed from a line-of-sight almost, but not exactly perpendicular to the motion direction, it could result in the variation of the instantaneous radial speed seen by (Krall et al. 2001; Shanmugaraju et al. 2010).

Coronal mass ejections (CME) striking the Earth elevate the activity index locally in time, thus making the forecast of the solar activity for a new solar cycle less reliable. Other coronal mass ejections have since been studied after they were detected in the last few decades. One example was the Halloween solar storms which occurred in October of 2003. However, the historical data on the strength and occurrences of coronal mass ejections only cover the last 30 years. The number of recorded events is insufficient for the data analysis. It has been observed that the coronal mass ejections are often produced after the eruption of solar flares. Thus, the collected geomagnetic index aa could be approximately

A study presented the statistical analysis of coronal mass ejections image by the Heliospheric Imager (HI) was conducted [31], compared the heliospheric CME characteristics with properties of CMEs observed at coronal altitudes, and with sunspot number and showed that heliospheric CME rates correlate with sunspot number as well as being more abundant, heliospheric CMEs, like their coronal counterparts, tend to be wider during solar maximum. Moreover, the results confirm that CME launch sites do not simply migrate to higher latitudes with increasing solar activity.

Aims. The diffuse morphology and transient nature of coronal mass ejections (CMEs) make them difficult to identify and track using traditional image processing techniques. We apply multiscale methods to enhance the visibility of the faint CME front. This enables an ellipse characterisation to objectively study the changing morphology and kinematics of a sample of events imaged by the Large Angle Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO) and the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) onboard the Solar Terrestrial Relations Observatory (STEREO). The accuracy of these methods allows us to test the CMEs for non-constant acceleration and expansion.

geomagnetic storms is the large IMF structure which has an intense and long duration southward magnetic field component, Bz [Tsurutani,et al, 1988 : Echer,et al, 2004]. They interact with the earth's magnetic field and facilitate the transport of energy into the earth's atmosphere through the reconnection process. .Correiaa and De Souza [2005] have presented the identification of solar coronal mass ejection (CME) sources for selected major geomagnetic storms in the geomagnetic field of geomagnetosphere. They have inferred that full halo CMEs originating from active regions associated with X-ray solar flares and propagating in the western hemisphere, cause strong geomagnetic storms. Michalek, G. et al [2006] have concluded that halo coronal mass ejections (HCMEs) originating from

of the solar corona. Theoretical investigations still cannot account for all the diverse manifestations of this energy release process in the solar atmosphere (Nivaor et al., 2011; Yaochen ., 2014). According to the current paradigm, the coronal magnetic field plays a dominant role in the CME eruption process. Modern CME theories usually consider the CME initiation process as taking place locally, i.e., in a relatively small (of the order of the active region size) part of the solar h the bipolar field configuration. Even in the breakout model which requires multipolar magnetic field, the opening of field lines has a local character: only the middle flux system erupts. There is, however, increasing evidence that tures on a larger spatial scale (Andrei Early measurements of the speeds of coronal mass ejections (CMEs) suggested that there are two distinct types of the speed profiles, slow CMEs which are associated with eruptive prominences and fast CMEs which originate in solar active regions. This classification was further supported by reports that the median speed of CMEs increases at the time nears a solar maximum and that flare associated CMEs have higher median speeds than those associated with eruptive 2005) Several other CME detection methods have proposed the generation of a number of CME catalogs, which do not always agree in terms of measured speeds or of event identification. There are INTERNATIONAL JOURNAL OF CURRENT RESEARCH

Coronal mass ejections (CMEs) are relatively a recently discovered phenomenon—in 1971, some 15 years into the Space Era. It took another two decades to realize that CMEs are the most important players in solar terrestrial rela- tionship as the root cause of severe weather in Earth’s space environment. CMEs are now counted among the major natural hazards because they cause large solar energetic particle (SEP) events and major geomagnetic storms, both of which pose danger to humans and their technology in space and ground. Geomagnetic storms discovered in the 1700s, solar flares discovered in the 1800s, and SEP events discovered in the 1900s are all now found to be closely related to CMEs via various physical processes occurring at various locations in and around CMEs, when they inter- act with the ambient medium. This article identifies a number of key developments that preceded the discovery of white-light CMEs suggesting that CMEs were waiting to be discovered. The last two decades witnessed an explosion of CME research following the launch of the Solar and Heliospheric Observatory mission in 1995, resulting in the establishment of a full picture of CMEs.

This paper describes the basic technological aspects of Digital Image Differencing technique in study of morphological properties with special reference to Coronal Mass Ejections. The former step deals with two images taken from SOHO satellite. The images are taken with a time interval. Then these two images are processed to get pure CME by using Digital Image Differencing. The enhancement procedures are applied to image data in order to effectively display. It involves techniques for increasing the visual distinction between features in a scene. The objective of the information extraction operations is to study Morphological properties of CMEs.

Carlson Center for Imaging Science in partial fulfillment of the requirements for the Master of Science Degree at the Rochester Institute of Technology Abstract Coronal Mass Ejections CM[r]

Some solar flares (known as eruptive flares) are associated with the eruption of a mag- netic structure containing a prominence (observed as a coronal mass ejection) and typically produce a two-ribbon flare, with two separating Hα ribbons joined by a rising arcade of flare loops. Others are contained and exhibit no eruptive behaviour. While some coronal mass ejections are associated with eruptive solar flares, others occur outside active regions and are associated with the eruption of a quiescent prominence. Coronal mass ejections out- side active regions do not produce high-energy products, because their magnetic and electric fields are much smaller than in eruptive solar flares, but their magnetic origin and evolution may well be qualitatively the same.

The complicated relationship between ICME signatures and identification of storms served as motivation for the completed thesis work; investigating if accelerometer data can be used as a potential new, characteristic signature for ICME identification, space weather monitoring, and solar storm characterisation. From the results presented in Chapter 5, this thesis has been able to demonstrate that satellite accelerometer data utilized by Random Forest and Extremely Randomized Trees binary classifiers can produce accurate results up to 82%. Features can be extracted from accelerometer data to successfully train a classifier to identify ICME events, which supports the claim that accelerometer data can be used as a supplementary characteristic signature to identify ICMEs, without further complex post-processing needed on the data. To be used in atmospheric modelling, the GRACE-A accelerometer data requires that the “mea- surements cannot be used directly and have to calibrated, as they are a ff ected by an instrument bias and scale” [18]. However, this thesis work has been able to show that, without calibration, a binary classifier can be trained on the accelerometer Level-1B ACC1B data of GRACE-A and perform well in identifying Interplanetary Coronal Mass Ejections from periods of quiet geomagnetic activity.

By the analysis we have selected those jumps in solar wind plasma temperature (JSWT) events which are associated with shock related geomagnetic storms and studied statistical behavior of these events with coronal mass ejections.

scintillation with the phase scintillation primarily caused by steep ionospheric density gradients and irregularities associated with auroral and cusp precipitation and polar cap patches (Spogli et al. 2009; Li et al. 2010; Prikryl et al. 2011a, b, 2013a; Jiao et al. 2013). The ionospheric dynamics in these regions is driven by the coupling be- tween solar wind, the magnetosphere, and ionosphere. Solar wind disturbances, in particular, the co-rotating interaction regions (CIRs) on the leading edge of high- speed streams (HSSs) and interplanetary coronal mass ejections (ICMEs) have been closely linked with the oc- currence of scintillation at high latitudes (Prikryl et al. 2012). These initial results demonstrated a technique of probabilistic forecast of phase scintillation occurrence in the cusp relative to arrival times of CIRs and ICMEs. Such scintillation prediction can be combined with as- sessment of the GNSS receiver tracking performance

Several studies indicate the role of solar flares and interplanetary shock waves due to CMEs in producing SEPs. Sun is an efficient particle accelerator and hence governs the energetic particles in the solar system. SEPs with energies from few 10s of keV to few GeV are accelerated near the Sun. They are classified into two different types of events (i) impulsive events and (ii) gradual events. The acceleration of electrons and charged nuclei to high energies is a phenomenon occurring at many astrophysical sites throughout the universe. In the heliosphere, processes in the solar corona associated with flares and coronal mass ejections (CMEs) are the most energetic natural particle accelerators, sometimes accelerating electrons and ions to relativistic energies (Droge 2003) 1 .The gradual SEP events cause high risk to the health of humans in space and in future colonies of humans on other planets within the solar system since they accompany very high energies (> 10s of MeV). They are also hazardous to spacecraft. The understanding of this gradual SEP events can be found in (Desai and Geacalone) 2 .

Abstract Coronal mass ejections are the outburst of solar energetic particle events, as a result of acceleration and heating of solar plasma during solar flares. Geomagnetic storms are caused by the interactions by materials ejected from the Sun, specifically, solar energetic particle events that lead to the disturbances in the Earth’s magnetic field. The results showed that geomagnetic activity on Earth’s atmosphere severely affected unexpected changes in charge particle density, which in turn, affected technology, power grids, and relative temperature on Earth. A fluctuation was found in the amount of the disturbed storm time index as the number of great geomagnetic storms noticeably raised the ascending and the descending phases of the cycle. The solar cycles have larger number of great geomagnetic storms in the ascending phase, however, more peaks occur during the descending phase. A low inverse correlation exists between disturbance storm time index and proton flux unit of the solar proton particles; and the disturbance storm time index and the proton flux unit of the solar proton particles during geomagnetic storms on Earth are apparently and significantly distributed differently.

The main objective in implementing an auto- mated detection and tracking routine is to out- put reproducible, robust, accurate CME measure- ments (height, width, position angle, etc.). Cur- rent methods of CME detection have their limita- tions, mostly since these diffuse objects have been difficult to identify using traditional image pro- cessing techniques. These difficulties arise from the transient nature of the CME morphology, the scattering effects and non-linear intensity profile of the surrounding corona, the presence of coro- nal streamers, and the addition of noise due to cosmic rays and solar energetic particles (SEPs) that impact the coronagraph detector, along with instrumental effects of stray light, the limitations imposed by low cadence observations, and data corruption or dropouts. In the introduction to this paper, the drawbacks of current cataloguing pro- cedures for investigating CME dynamics (CDAW, CACTus, SEEDS, ARTEMIS) were highlighted as the motivation for establishing a new cata- logue. However, given the highly variable nature of CME phenomena and the coronal atmosphere they traverse, there are certain limitations that can never be overcome but only minimized; and it is exactly such a minimizing of current limita- tions that these new CORIMP methods achieve. The methods are completely automated, mak- ing them robust and reproducible - important for back-dating the full LASCO dataset and inspect- ing the statistics across thousands of events. The automated detection has been extended through both the LASCO/C2 and C3 fields-of-view with- out any need for differencing, thus minimizing the issues of under-sampling events and of the uncer- tainty involved when subtracting and scaling im- ages. The multiscale filtering technique reveals the CME structure and so minimizes the uncertainty in determining their often complex geometry. The number of scales in the multiscale decomposition also allows a strength of detection to be assigned through both the magnitude and angular infor- mation, thus minimizing the chances that a CME, or parts thereof, go undetected. Furthermore, the spread of measurements available for inspection of the CME kinematics minimizes the uncertainty involved when deriving velocity and acceleration profiles, which is important for comparing with physical theory of CME propagation. Indeed, the

Following the observations, CME initiation models can also be divided into two broad categories: models with pre- existing FRs and models with FR formation during the erup- tion. Most models that form twisted magnetic structures above the photosphere in a self-consistent manner use a buoyant sub-photospheric flux tube as initial condition. Such a sub- photospheric flux tube emerges partially and creates a magnetic envelope field (e.g. Archontis et al. 2004). Photospheric shear- ing motions cause tether-cutting of the field lines (similar to van Ballegooijen & Martens 1989), creating a post-emergence flux rope above the solar surface (e.g. Magara & Longcope 2001). The resulting post-emergence flux ropes can lead to either con- fined (i.e. FR acceleration is inhibited by the envelope field) or ejective eruptions (i.e. FR escapes the simulation box). This de- pends on the initial conditions, such as the initial flux tube mag- netic field strength, the presence of an external field and its ori- entation, and the shape of the flux tube (toroidal, cylindrical) (e.g. Manchester et al. 2004; Archontis & Hood 2010; Archon- tis et al. 2014). Cases of confined FR eruptions are associated with the formation of quasi-stable coronal twisted flux ropes. Article number, page 1 of 14

A Coronal Mass Ejection (CME) is an ejection of energetic plasma with magnetic field from the Sun. In traversing the Sun-Earth distance, the ki- nematics 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 interplaneta- ry 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.

The availability of space-based coronagraphs and heliospheric imagers on-board SOHO and STEREO spacecraft over the last two decades permitted continuous observations of coro- nal mass ejections (CMEs), providing an unprecedented view of these and other dynamic phenomena occurring in the solar corona (see review by Webb & Howard 2012). The visible light (VL) imaging of CMEs allowed many authors to study the details of many CME properties, such as their kine- matics, masses, external forces acting during their propaga- tion, three-dimensional (3D) structure, and CME-driven shocks (see e.g., Bemporad & Mancuso 2010; Colaninno & Vourlidas 2009; Gopalswamy & Yashiro 2011; Ontiveros & Vourlidas 2009, Michałek et al. 2003; Mierla et al. 2010; Rouillard et al. 2011; Thernisien et al. 2009; Yashiro et al. 2004; Zhang et al. 2004). Moreover, the availability of a large amount of data provided an opportunity to study CMEs and their relation- ships (from a statistical point of view) to other phenomena