Study of coronal mass ejections (CMEs) using STEREO and SOHO observations A dissertation presented by Anitha Ravishankar written under the supervision of dr hab. Grzegorz Michałlek to The Faculty of Physics, Astronomy and Applied Computer Science Jagiellonian University Krakow, Poland 2020 ©c 2020 — Anitha Ravishankar: Study of coronal mass ejections (CMEs) using STEREO and SOHO observation. All rights reserved. Acknowledgments Family, friends, teachers and the Eternal force for providing me with a curious mind! My PhD journey has been nothing short of a fairytale. Supportive parents and a gaurdian angel brother have been my backbone. It isn’t easy for an indian family to comfortably encourage their daughter to pursue her dreams. Starting with late night visits to the planetarium upto attending summer schools at observatories located at the most remote places in India. A huge leap of faith was taken as the daughter wanted to pursue this long journey not far away from the hometown but much far away from the home country. A lot of trust and confidence is required. Hence stressing the fact that the family is a backbone is no exaggeration. I have been blessed with amazing friends and supportive teachers throughout my life. Sometimes a little appreciation amplifies a lot of power to cross barriers and these boosts of power were my friends and mentors. To all you amazing people in my life, a big heartfelt thanks to you all. I shall come in person to convey my gratitude in the future, no matter where you are on this beautiful planet. Nothing but positivity has surrounded me. The very fact that the whole PhD journey has been an everlasting beautiful memory is all because of my supervisor. Professor, thank you for believing in this young girl from India and providing me this golden opportunity to contribute a little to the plethora of knowledge. Honestly, I definitely wouldn’t have done this without you. Your patience towards my mistakes and your encouraging words even at tough times were the exact qualities a student would expect from their supervisor, and you have kindly provided me with those. I shall be ever grateful to you for this. ˙ Dzi¸ekuj¸e bardzo! iii Abstract This dissertation is an attempt to understand the kinematics of coronal mass ejections (CMEs) as it propagates in the interplanetary medium. Particularly, our aim is to study the Earth-directed (halo and partial-halo) CMEs as these are of immediate concern as they can cause geomagnetic storms on Earth. These intense expulsions of magnetized plasma give rise to shocks that accelerate particles such as protons, electrons and few heavy ions. These accelerated particles are known as solar energetic particles (SEPs) and in the aspect of potential space weather impacts, these particles with high proton fluxes are the prime threats in causing disturbances of Earth’s magnetosphere and upper atmosphere. On the contrary, SEPs are also responsible for the cause of Auroras. Hence, accurate prediction of SEPs can prepare us to know if we would face a threat or a beautiful marvel, sooner or later. The interdependence of the three most powerful phenomena on the Sun, i.e., the solar flares, CMEs and SEPs is one of our main objectives in the study. Eventually estimating their arrival times in the vicinity of Earth to evade space weather hazards is our scientific merit. In addition, we investigate the variation of two most important kinematic properties of CMEs, i.e., velocity and acceleration during the last two solar cycles, 23 and 24. The analysis were performed using mainly the data of Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph (SOHO/LASCO) and quadrature observations by Solar Terrestrial Relations Observatory/Sun Earth Connection Coronal and Heliospheric Investigation (STEREO/SECCHI) for CMEs, Geostationary Operational Environmental Satellites GOES-13 for SEP fluxes and GOES-14 for solar flare fluxes. All these results could be very useful for forecasting of space weather. iv List of publications This dissertation has been written as a summary of the scientific activities previously reported in the following articles: 1. Ravishankar, A., Michalek, G., Estimation of Arrival Time of Coronal Mass Ejections in the vicinity of the Earth using SOHO and STEREO Observations, 2019, Solar Physics, 294, 125, [10.1007/s11207-019-1470-2]. 2. Ravishankar, A., Michalek, G., Non-Interacting Coronal Mass Ejections and Solar Energetic Particles near the Quadrature Configuration of Solar TErrestrial RElations Observatory, 2020, Astronomy & Astrophysics, 638, A42, [10.1051/00046361/202037528]. 3. Ravishankar, A., Michalek, G., Yashiro, S., Kinematics of coronal mass ejections in the LASCO field of view, 2020, Astronomy & Astrophysics, 639, A68, [10.1051/0004-6361/202037834]. 4. Ravishankar, A., Michalek, G., Relationship between solar energetic particle intensities and coronal mass ejection kinematics using STEREO/SECCHI field of view, 2020, Astronomy & Astrophysics, [10.1051/0004-6361/202039537]. v Acronyms ACE Advanced Composition Explorer. AIA Atmospheric Imaging Assembly. CME Coronal Mass Ejection. COR Coronagraph. DSA Diffusive Shock Acceleration. dst Disturbance Storm Time. EPS Energetic Particle Sensor. GLE Ground Level Enhancement. GOES Geostationary Operational Environmental Satellites. HI Heliospheric Imager. ICME Interplanetary Coronal Mass Ejection. IMF Interplanetary Magnetic Field. . IP Interplanetary. LASCO Large Angle and Spectrometric Coronagraphs. SDO Solar Dynamics Observatory. SECCHI Sun Earth Connection Coronal and Helio spheric Investigation. SEM Synchronous Environmental Satellites. SEP Solar Energetic Particles. SMM Solar Maximum Mission. SOHO Solar and Heliospheric Observatory. SPE Solar Particle Event. STEREO Solar Terrestrial Relations Observatory. TT Travel Time. vi Contents Acknowledgments iii Abstract iv I Current state of the knowledge 1 1 Introduction 2 1.1 Sunandspaceweather .......................... 2 1.2 Coronalmassejections .......................... 3 1.3 CMEsandSolarenergeticparticles ................... 4 1.4 Spacecrafts ................................ 6 II Results of the published articles 8 2 Aims and objectives of the thesis 9 2.1 Estimation of Arrival Time of Coronal Mass Ejections in the Vicinity of the Earth Using SOlar and Heliospheric Observatory and Solar TErrestrial RElations Observatory Observations . . . . . . . . . . . . 9 2.2 Non-Interacting Coronal Mass Ejections and Solar Energetic Particles near the Quadrature Configuration of Solar TErrestrial RElations Observatory ................................ 11 2.3 Kinematics of coronal mass ejections in the LASCO field of view . . 13 vii CONTENTS 2.4 Relationship between solar energetic particle intensities and coronal mass ejection kinematics using STEREO/SECCHI field of view . . . 14 3 Final conclusions 17 References 18 III Publications 21 viii Part I Current state of the knowledge 1 Introduction 1.1 Sun and space weather Curiosity over the bright yellow object, now commonly termed as Sun, has been among the first cosmic entities that gave birth to the field of astronomy. Years of understanding has paved way to realize its importance and vitality for life on Earth and balance in our solar system. Centuries of observations through naked eye and basic telescopes have unlocked several mysteries of our Universe. And with the advent of spaceborne satellites, housing telescopes at multi-wavelengths, has helped answer several questions in physics which are crucial for understanding several sources in our cosmos. Although appears to be stable and balanced from the Earth, Sun is an active source whose dynamicity is governed mainly by varying magnetic fields. The gaseous giant, regulated by extremely high temperatures of about 14 million (core)-5,500 (surface) degrees celsius, converts almost all of the hydrogen into ionized state called plasma. This state of matter sets off different layers of the Sun in motion causing a phenomenon called as differential rotation. Few of the most prominent discoveries of the Sun were by R. C. Carrington that included determination of the Sun’s rotation axis, the latitudinal variation of sunspots over a solar cycle, and the differential rotation of the poles compared with the equatorial regions during the 19th century (more on Carrington’s scientific works can be found in the article by Cliver & Keer 2012). The most powerful signatures of the Sun’s dynamicity are solar flares, coronal mass ejections (CMEs), sunspots and prominences. The rate of their occurrence varies with the nearly periodic 11-year cycle called as the solar cycle or solar magnetic activity cycle. In the course of this period, the north and south magnetic poles switch their polarity and return back in 2 another 11-years (22 years in total) to restore to its original state. The solar transients such as CMEs, solar energetic particles (SEPs) and solar wind play a crucial role in the changes of conditions in the interplanetary space of our solar system. Specifically, when these ionized protons and electrons carrying magnetic fields interact with the Earth’s magnetosphere, ionosphere and thermosphere, they can cause geomagnetic storms accompanied by Aurorae. This field of study is known as space weather and research in this area is of utmost importance as the consequences of these storms, depending on their intensities, could be devastating. Accurate predictions of space weather forecasts is crucial as solar storms cause catastrophic damages to power grids on Earth and are serious radiation threat to satellites on low-Earth orbit and their crew during spacewalks. The motivation for this study is derived from studying the impact of large solar storms recorded in the history. Of the few, the two most prominent events, 1859 Carrington event and 1989 geomagnetic storm, till date are known to be the most powerful solar storms. The 1989 solar storm is of peculiar interest as the disturbance storm index (dst) reached a value of -589 nT, as a consequence, the province of Quebec, Canada, experienced a 12 hour blackout. In space, several satellites recorded anomalies and persisted only during the time the solar storm passed across (Boteler 2019). Though rare, a repeat of such events at present time will cause extensive damages and disrupt lives at large scale. An accurate prediction model to estimate the arrival time of large solar storms and ground level enhancements (GLEs -having energies exceeding 1 GeV) can offer precautionary measures to mitigate damages. 1.2 Coronal mass ejections CMEs are large-scale eruptions of magnetized plasma from the Sun that propagate in the heliosphere. These are one of the prime sources of material for solar wind and their rate of occurrence depends on the solar activity, i.e., several per day during maximum and several per week during the minimum of a solar cycle. The eruption timescales vary from several minutes to hours (Hundhausen et al. 1994). Solar flares and CMEs share a common mechanism of eruption, i.e., magnetic reconnection. Magnetic reconnection occurs when a magnetic field line rearranges itself to move to a lower-energy state. As field lines of opposite polarity reconnect, magnetic energy is suddenly converted into an outburst of thermal and kinetic energy (Chen 2016). The material and energy thus released are carried by CMEs of varying temperatures such as coronal (2 MK) material in the front followed by cool prominence (8000 K) material in some cases and hot flare-material (10 MK) in others. The most common 3 structure of CMEs are typically of three part: a leading front, a dark cavity, and a bright core (Crifo et al. 1983). In the course of its propagation in the interplanetary medium, the width of the CMEs usually increase as they expand. The rate of expansion of CMEs mainly depends on the Lorentz force that drives them and the conditions prevailing in the interplanetary medium (Chen 1996, Kumar & Rust 1996 Kliem & T¨or¨ok 2006). These powerful clouds of ionized gases bound by magnetic field can travel at average speeds of 450 kms−1 (Yashiro et al. 2004; Webb & Howard 2012). The yearly average CME speed changes with the solar cycle (Yashiro et al. 2004) from 300 kms−1 during the minimum to 500 kms−1 during the maximum of solar activity. CMEs play an important role in controlling space weather. If directed towards the Earth (Halo or partial-halo CMEs), they can interact with Earth’s magnetic field and cause geomagnetic disturbances (e.g.,Gopalswamy et al. 2001,Gopalswamy et al. 2002, Gopalswamy 2002; Srivastava & Venkatakrishnan 2002; Kim et al. 2005; Moon et al. 2005; Manoharan et al. 2004; Manoharan 2006; Manoharan 2010; Manoharan & Mujiber Rahman 2011; Shanmugaraju et al. 2015). For geomagnetic storm forecasting it is crucial to predict when a solar disturbance would reach the Earth. This is not an easy task because the rate of expansion of ejections depend on the magnetic force that drives them and the conditions of its propagation vicinity. In addition, the ejection velocity can change rapidly as a result of CME-CME interactions. The CME-like disturbance observed in the solar wind are called as Interplanetary CME (ICME) and when the ejecta contains ordered magnetic field it is known as a magnetic cloud (Burlaga et al. 1981). These structures are relevant for in situ observations at 1 AU. 1.3 CMEs and Solar energetic particles The two most powerful factors that control space weather are solar flares and CMEs. As a consequence of these powerful outbursts on the Sun, energetic protons and ions, known as solar energetic particles (SEPs), are accelerated at high speeds. The acceleration is mainly due to shocks induced by CMEs (e.g., Cane et al. 1987; Reames 1999; Kahler 2001; Gosling 1993) or at the magnetic reconnection regions of solar flares (Cane et al. 1986). As a practical consequence, Earth-directed (halo and partial-halo) large SEPs are of immediate concern as they can penetrate the magnetosphere causing widespread electrical disruptions in the regions close to the poles and to the passengers of high-altitude aircrafts flying in polar routes. SEPs are classified into two types, the impulsive and short lived SEP events are associated to flares, whereas, the large, gradual, and long-lived SEP events are well correlated to the associated CMEs. (e.g., Cane et al. 1987; Reames 1999; Kahler 2001; Gosling 4 1993). Due to their long life, the gradual events survive the journey to the Earth and cause susceptible damage. The diffusive shock acceleration (DSA) theory has been well studied and widely accepted mechanism for energizing the ions in gradual SEP events (e.g., Jokipii 1982; Lee 1983, Lee 2000; Lee et al. 2012; Desai & Giacalone 2016). Charged particles can be accelerated by collisionless shocks provided spatial diffusion allows some particles to traverse the shock many times. They gain energy because the scattering centers are embedded in converging plasma flows across the shock. In addition, the particles existing in the interplanetary medium that were produced by the preceding CME provides seed particles for the primary CME. This scenario is crucial for space weather forecasts since the acceleration of already existing seed particles would drive the particles to farther distances away from the Sun. In the case of halo-CMEs, this proves to be an important problem to understand. CMEs drive powerful interplanetary (IP) shocks, which in turn accelerate electrons and ions over extended periods of time. A good indicator of SEPs accelerated due to coronal and interplanetary shocks are type II radio bursts (Cliver et al. 1999). These bursts are caused by electrons accelerated by shocks (see e.g. Kahler 1982; Kahler et al. 2000; Cane et al. 2002; Cliver et al. 2004; Gopalswamy et al. 2005; Cho et al. 2008). Gradual SEPs are often associated with metric type II bursts (150 to 15 MHz) and are generated close to the Sun ≤ 3RSUN (Gopalswamy et al. 2009b). Hence, in situ radio observations by spacecrafts can be used to detect CME-driven SEPs at 1 AU. Magnetic field lines are the roads for propagation of charged particles. The large-scale magnetic field lines extending in the interplanetary space from the Sun are called Parker Spirals. Location of the eruption is very important. Flare-driven SEPs travel directly along the lines and are observed at 1 AU. This directly tells us the location of eruption. CME-driven SEPs can be accelerated by shocks evolving in the interplanetary space as the shock fronts can connect to multiple field lines making the determination of their exact source location hard to trace back. Although a good extent of knowledge is gained about SEPs, there are several crucial understandings from the point of view of space weather yet to be unravelled. For example, quantifying the relative roles of flare-related magnetic reconnectiondriven acceleration processes, CME-shock associated DSA and other mechanisms. In addition, understanding the coronal and interplanetary magnetic field configurations affecting the energization and escape of SEPs from their acceleration regions are of prime importance (Desai & Giacalone 2016). In the next section we summarize the contributions of spaceborne telescopes in understanding pivotal roles of CMEs and SEPs in causing geomagnetic storms. 5 Figure 1.1: 23 January 2012 event of a Coronal Mass Ejection (top left) and the associated Solar Energetic Particles (top right) seen by the SOHO/LASCO C2 coronagraph with a composite image by SDO/AIA. The SEPs, seen as white grains in the field of view on right, onset approximately 4 hours after the CME eruption. The same event seen by STEREO-A/SECCHI coronagraphs COR1, COR2 and heliographic imagers HI1, HI2. The evolution of CME varying with time and distance are clearly seen as bright structures. 1.4 Spacecrafts Spacecraft instruments can directly sample the CMEs. The first CME was recorded by the coronagraph on board the 7th Orbiting Solar Observatory (OSO-7) satellite (Tousey 1973). Since that time, several spaceborne coronagraphs, such as the Apollo Telescope Mount coronagraph (MacQueen et al. 1974) on board Skylab, the Solwind coronagraph on board the P78-1 satellite and the Coronagraph/Polarimeter (MacQueen et al. 1980) on board the Solar Maximum Mission (SMM) have dedicated studies on Sun. Because in our study we use observations mostly from two satellites we shortly describe them below. Since 1996 there has been large contributions to extensive knowledge on solar transients thanks to the Large Angle and Spectrometric Coronagraph (LASCO, Brueckner et al. 1995) coronagraph on board the Solar and 6 Heliospheric Observatory (SOHO) mission (Domingo et al. 1995). The LASCO coronagraphs (C2, and C3) cover a field of view of about 1.5 -32 RSUN and in the past two decades there has been over 30,000 CMEs observed. The basic attributes of CMEs, determined manually from LASCO images, are stored in the SOHO/LASCO catalog 1 (Yashiro et al. 2004; Gopalswamy et al. 2009a). When the accuracy of determination of true speeds of halo CMEs is discussed, it is worth noting that the coronagraphic observations are subject to projection effects as the spacecraft is placed at L1 which is not ideal for Earth-directed CMEs. Due to the projection effects, the speeds obtained provide inaccurate forecast of geoeffective events originating from the disk center (Michalek et al. 2019). In order to obtain accurate speeds as well as a 360◦ view of the Sun, so that CMEs erupting at the backside can also be studied, the Solar Terrestrial Relations Observatory (STEREO, Kaiser et al. 2008) spacecraft was launched in 2006. The Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI, Howard et al. 2008) instruments on board the twin spacecrafts STEREO-A and -B, during their quadrature configuration, i.e., at ≈90◦ separation with respect to the Earth, offer an advantage in the accurate determination of plane-of-sky speeds which are close to the true radial speed of halo CMEs with insignificant projection effects (Bronarska & Michalek 2018). Another advantage of STEREO/SECCHI is that it offers a wider range of observation (1.5 -318 RSUN ) in contrast to SOHO/LASCO C2/C3 field of view which helps track the kinematics of a CME throughout its propagation in the interplanetary medium accurately upto 1 AU. Manual measurements of height-time data points are performed with the data of coronagraphs, COR1, COR2 and the heliospheric imagers, HI1 and HI2, on board SECCHI2 to determine the speed of CMEs. In this dissertation, we highlight our statistical and comparative studies performed on the kinematics of CMEs using extensively the data of SOHO/LASCO and STEREO/SECCHI. 1cdaw.gsfc.nasa.gov/CME list 2https://www.ukssdc.ac.uk/solar/stereo/data.html 7 Part II Results of the published articles Second part of this dissertation is a summary of our scientific analysis on understanding the kinematics of CMEs with varying timescales and their influence on the associated SEPs. The results provide an overall picture on geomagnetic storms and space weather. Relevant publications were discussed and final conclusions were drawn. Publications are presented in chronological order. 8 Aims and objectives of the thesis As we have addressed clearly in the previous sections on the problems pertaining Earth’s and spacecraft instruments by the solar transients such as flares, CMEs and SEPs, we have conducted studies on understanding their physical mechanisms and devising methods to predict their arrival times at Earth. For geomagnetic storm forecasting it is crucial to predict when a solar disturbance would reach the Earth. Several ground based and spaceborne telescopes have performed dedicated observations of solar transients yet further detailed analysis is required for accurate predictions of their arrival time at Earth. Among the four papers included in the doctoral dissertation, three papers concentrate on the important issues concerning CMEs and space weather and one paper presents the variation of kinematics of CMEs during solar cycles 23 and 24. Using the data of SOHO and STEREO we present the kinematics of CMEs and with the help of GOES-13 we show the relationship between CMEs and the associated SEPs. The obtained results could be very useful for forecasting of space weather. 2.1 Estimation of Arrival Time of Coronal Mass Ejections in the Vicinity of the Earth Using SOlar and Heliospheric Observatory and Solar TErrestrial RElations Observatory Observations Based on Ravishankar, A., Michalek, G., 2019, Solar Physics, 294, 125. 9 The first article concentrates on determination of arrival time of CMEs in the vicinity of the Earth which is one of the most important parameters in determining space weather. For this purpose we focused on halo and partial-halo CMEs during the ascending phase of solar cycle 24 (2009-2013). The data from SOHO/LASCO and STEREO/SECCHI was used and the instantaneous velocities such as average and maximum velocities for individual spacecrafts [VAV G−SOHO,VAV G−ST EREO, VMAX−SOHO,VMAX−ST EREO] were determined to obtain the best indicator to predict the arrival time of CMEs. During this period the STEREO twin spacecrafts were in quadrature position in relation to the Earth. We demonstrated that these conditions of STEREO observations can be crucial for an accurate determination of the transit times (TTs) of CMEs to the Earth. The main purpose of the research is to develop an empirical model to predict TTs of CMEs with better accuracy than previous models used in literature. We mainly used the quadrature configuration of STEREO twin spacecrafts, i.e., at ≈90◦ separation with respect to the Earth offer an advantage in the accurate determination of plane-of-sky speeds which are close to the true radial speed of halo CMEs with insignificant projection effects which was seen during 2009-2013. 51 good quality halo/partial-halo CMEs were chosen for the statistical study. In addition we performed comparative analysis with the data of SOHO with the selected set of CMEs. The STEREO observations in quadrature provide speeds that are very close to spatial (real) velocities, whereas measurements with SOHO provide speeds that are significantly modified by projection effects. We are interested on how these different speeds can be used to determine the TT of a CME to the Earth. The speeds from SOHO were obtained using the SOHO/LASCO catalog and for the STEREO (COR2+HI1) speeds of CMEs, we have performed identical manual measurements as in the case of the LASCO observations. To determine the instantaneous velocity profiles we used linear fits to five height–time data points. Shifting successively these five point linear fits, we obtained the instantaneous profiles of speed in time and in distance from the Sun. Technically, two neighboring height–time points are enough to determine the instantaneous speed, but as manual measurements are subject to unpredictable random errors, we used five successive points to obtain the most reasonable results. In addition, we applied a linear fit to the height–time data points to further minimize the impact of errors on the determined instantaneous speed. We defined a new initial velocity of the CME, the maximum velocity and have used this parameter for further study. The motivation to use this approach is to determine if the maximum velocity can offer a better correlation than the method of average speeds that was extensively used in the literature. The new approach has provided promising results in comparison to previous 10 methods. It was demonstrated that all of the considered initial speeds i.e., the average and maximum speeds of SOHO and STEREO are significantly correlated, however, the most significant correlation appears to be between the velocities determined using the same spacecrafts. The maximal velocities are larger by about 80% and 25% than the average velocities for the STEREO and SOHO telescopes, respectively. The initial velocities determined in the STEREO images are also significantly related to the final velocities of an ICME. It is also worth noting that in the case of maximum speeds, the empirical model obtained from the correlation between these speeds and TT are in good agreement. However, what is more important is the fact that the new approach has radically reduced the maximum TT estimation errors to 29 hours. Previous studies determined the TT with a maximum error equal to 50 hours. Therefore, the best instantaneous speed parameter of a CME that can be used for prediction of their arrival times is maximum velocity using STEREO data. The model presented can be used universally. As input to this model, we can use speeds or accelerations obtained in different ways. In particular, we can use the real three dimensional speeds estimated using stereoscopic observations from all coronagraphs. This is a very important result from the point of view of space weather. This allows us to accurately predict one of the most important parameters determining the geoeffectiveness of CMEs. 2.2 Non-Interacting Coronal Mass Ejections and Solar Energetic Particles near the Quadrature Configuration of Solar TErrestrial RElations Observatory Based on Ravishankar, A., Michalek, G., 2020, Astronomy & Astrophysics, 638, A42. The second article focuses on the relationship between the three most intense solar transients, i.e., the solar flares, CMEs and SEPs. The generation of SEPs is mainly due to two phenomenon, impulsive SEP events caused by magnetic reconnection manifested as solar flares and gradual SEP events accelerated by strong shocks associated with CMEs. The large, gradual, and long-lived SEP events are of particular interest as the arrival of the associated ICME, shock and the enhanced SEP fluxes can cause severe damages to satellites in space and technology on the ground. It is well known that the CME speeds and SEP intensities are closely correlated. We further examine this correlation by employing instantaneous speeds 11 (maximum speed and the CME speed and Mach number at SEP peak flux), that have never been used before as seen in literature, to check whether they are a better indicator of SEP fluxes than the average speed. SEP intensities and CME speeds are well correlated and several evidences are provided in the scientific literature. It is worth to note that these considerations were based on average velocities of CMEs. In this article, we continue to determine these correlations by employing our new approach of using the instantaneous speeds of CMEs of non-interacting halo CMEs near the quadrature configuration of STEREO/SECCHI. Comparative studies with SOHO/LASCO data was also performed. All the four coronagraphs, COR1, COR2, and the heliospheric imagers, HI1 and HI2 on board SECCHI were used to analyse the propagation of the CME. The SEP fluxes at three energy bands, >10 MeV, >50 MeV and >100 MeV from the Geostationary Operational Environmental Satellite (GOES-13) Energetic Particle Sensor (EPS), part of the Space Environment Monitor (SEM), was used to study −1 −1 SEP intensities. Flux limit of ≥1 pfu (1 pfu = 1 proton cm−2 ssr)inthe >10 MeV energy band was chosen for the study. In addition, we discuss the relation of the X-ray peak flux of solar flares using GOES-14 data associated with the two phenomena. With the set criteria we obtained 25 SEP events and the associated non-interacting CMEs and flares during the ascending phase of solar cycle 24, i.e., 2009–2013 for further analysis. Our preliminary results show a better correlation by this approach. We investigated the correlation coefficients using average, maximum and CME speed at SEP peak fluxes. Average velocities offer poor correlations and this value has improved with maximum speed. However, the best kinematic property to use is the CME velocity at SEP peak fluxes. The best correlation is observed for instantaneous ejection speeds recorded at the time of maximum particle energy fluxes as this parameter is nominal for events erupting even at eastern longitudes. Correlations between the velocities of CME and maximum fluxes of protons are poorer for SOHO observations than for STEREO data. In addition, the correlation coefficients show that the fluxes of protons in energy channel >10 MeV are accelerated by shock waves generated by fast CMEs, whereas the particles of >50 MeV and >100 MeV energy bands are mostly accelerated by the same shock waves but partly by the associated flares. Nevertheless, the correlation between SEP intensities and CME speed or X-ray intensity is not sufficient to completely deny combined participation of both CME-related and flare-related acceleration due to the interdependence of the two phenomena. In contrast, the X-ray flux of solar flares and SEP peak flux show a poor correlation. The CME maximum and average velocities obtained by STEREO/SECCHI are moderately correlated with intensities of associated X-ray 12 flares. We do not observe this correlation for the data obtained from SOHO. 2.3 Kinematics of coronal mass ejections in the LASCO field of view Based on Ravishankar, A., Michalek, G., Yashiro, S., 2020, Astronomy & Astrophysics, 639, A68. The correlation between the solar cycle and the number of CME eruptions are one of the most interesting topics in solar physics. Particularly, studies on the changes in CME kinematic profiles such as velocity and acceleration offers valuable information on whether there is any certainty that these parameters follow the cycles of solar activity. Detailed study on this will provide crucial information on potential geoeffective CMEs even during the solar minimum when it is least expected to be harmful. With this motivation we conducted statistical analysis on CMEs during solar cycles 23 and 24. In this article we conducted a statistical study of the kinematics of 28894 CMEs recorded by SOHO/LASCO spacecraft from 1996 until mid-2017. The data from SOHO has been particularly chosen as the spacecraft covers the solar cycle 23 completely and 24 upto the descending phase. The basic attributes of CMEs, determined manually from running difference images, are stored in the SOHO/LASCO catalog. The two basic parameters, velocity and acceleration of CMEs, are obtained by fitting a straight and quadratic line to all the height-time data points measured for a given event. The parameters determined in this way, in some sense, reflect the average values in the field of view of the LASCO coronagraphs. Nevertheless, it is evident that both these parameters are continuously changing with distance and time after CME onset from the Sun. Therefore, the average values of velocity and acceleration, used in many studies, do not give a correct description of CME propagation. Using our method we estimated the introduced parameters characterizing the kinematics of CMEs in different phases of their expansion. We were able to determine initial acceleration and residual acceleration for 21492 (74%) and 17092 (60%) events, respectively. The results obtained in our study shows that the initial acceleration phase is characterized by a rapid increase in CME velocity just after eruption in the inner corona. This phase is followed by a non-significant residual acceleration (deceleration) characterized by an almost constant speed of CMEs. The initial acceleration is in the range 0.24 -2616 ms−2 with median (average) value of 57 13 ms−2 (34 ms−2) and it takes place up to a distance of about 28 RSUN with median (average) value of 7.8 RSUN (6 RSUN ). Additionally, the initial acceleration is significant in the case of fast CMEs (V >900 kms−1), where the median (average) values are about 295 ms−2 (251 ms−2), respectively, and much weaker in the case of slow CMEs (V <250 kms−1), where the median (average) values are about 18 ms−2 (17 ms−2), respectively. More importantly, the significant driving force (Lorentz force) can operate up to a distance of 6 RSUN from the Sun during the first 2 hours of propagation. We found a significant anti-correlation between the initial acceleration magnitude and the acceleration duration, whereas the residual acceleration covers a range from -1224 -0 ms−2 with a median (average) value of -34 ms−2 (-17 ms−2). One intriguing finding is that the residual acceleration is much smaller during the 24th cycle in comparison to the 23rd cycle of solar activity. Our study has also revealed that the considered parameters, initial acceleration, residual acceleration, maximum velocity and time at maximum velocity mostly follow solar cycles and the intensities of the individual cycle. 2.4 Relationship between solar energetic particle intensities and coronal mass ejection kinematics using STEREO/SECCHI field of view Based on Ravishankar, A., Michalek, G., 2020, Astronomy & Astrophysics, accepted. Proceeding with the initial results obtained from our second paper on the correlation between flares, CMEs and SEPs, we further investigate these two phenomenon in detail. We limit the analysis to only the CMEs and SEPs as poor correlations were seen between the peak intensities of flares and SEPs in both SOHO and STEREO data. In addition, we obtained best correlations using STEREO/SECCHI data for CMEs in comparison to SOHO/LASCO. Therefore in this article we explore the parameters limiting to STEREO data. Gradual SEPs accelerated from shocks driven by CMEs are one of the major causes of geomagnetic storms on Earth. Therefore it is necessary to predict the occurrence and intensity of such disturbances. The literature and our previous article has shown that CME speeds are well correlated with SEP peak intensities but we further investigated if a better parameter, such as instantaneous Mach number, could offer a higher correlation. Several works by other authors also suggest that the Mach number of IP shocks is one of the primary parameters controlling the intensity of SEPs measured in the vicinity of the Earth. Hence with this motivation we proceed to analyse these 14 parameters. The scientific merit of our work is to provide a potential model for prediction of large geoeffective SEPs. We analyzed in detail 38 non-interacting halo and partial halo CMEs, as seen by SOHO/LASCO, generating SEPs (in >10 MeV, >50 MeV and >100 MeV energy channels) during the quadrature configuration of STEREO twin spacecrafts with respect to the Earth, which marks the ascending phase of solar cycle 24, i.e., 2009-2013. Using the data from STEREO/SECCHI images we determined several kinematic parameters and instantaneous speeds of the CMEs. The comparative studies presented in our second article have also shown that STEREO/SECCHI offers a wider range of observation (1.5 RSUN -318 RSUN ) in contrast to SOHO/LASCO C2/C3 field of view (1.5 RSUN -32 RSUN ). Therefore, in this paper we completely dedicated the kinematic study of CMEs with STEREO/SECCHI data as we can study the CME evolution at large distances from Sun, during peak SEP intensities in the heliosphere. The SEP fluxes at three energy bands, >10 MeV, >50 MeV and >100 MeV was analysed using GOES-13 data at flux limit of ≥1 pfu in the >10 MeV, ≥0.1 pfu in the >50 MeV and ≥0.05 pfu in the >100 MeV energy band was chosen for the study. The properties of the DH type II bursts that are signatures these CME-driven shocks can be obtained from database of WIND/Waves and STEREO. Using the models for Alfv´en speed, solar wind speed and the our manual measurements for CME speed, the instantanous Mach number was determined as MA =VCME/(VA +VSW ). Firstly, we compare instantaneous CME speed and Mach number versus SEP fluxes for events originating at western and eastern limb and we observe high correlation for west events and anti-correlation for east events. Of the two parameters, the Mach number offers higher correlation. Next we investigate instantaneous CME kinematic parameters such as maximum speed, maximum Mach number and the CME speed and Mach number at SEP peak flux versus SEP peak fluxes. Highly positive correlation is observed for Mach number at SEP peak flux for all events. The obtained instantaneous Mach number parameters from the empirical models was verified with the start and end time of type II radio bursts which are signatures of CME-driven shock in the interplanetary medium. Furthermore, we conducted estimates of delay in time and distance between CME, SEP and shock parameters. We observe increase in the delay in time and distance when SEPs reach peak flux with respect to CME onset as we move from western to eastern limb. West limb events (longitude 60◦) have the best connectivity and this decreases as we move towards eastern limb. This variation is due to the magnetic connectivity from Sun to the Earth, i.e., Parker spiral interplanetary magnetic field (IMF). Comparative studies on the considered energy channels of the SEPs also throw light 15 on the reacceleration of suprathermal seed ions by CME-driven shocks that are preaccelerated in the magnetic reconnection. 16 Final conclusions We have obtained several interesting results which are included in the respective papers. Here we present only four general conclusions that highlight the most important new results: 1. It was shown that the maximum speed over average speed is a better approach to predict the arrival time of CMEs as the new approach has radically reduced the maximum TT estimation errors from 50 hours to 29 hours. 2. Instantaneous CME speeds such as maximum speed and maximum Mach number using STEREO data offers best correlation with associated SEPs which are better than previously used indicators like average speeds. Solar flares and SEPs show poor correlations. 3. We considered instantaneous parameters of CMEs in SOHO field of view. 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A. 2012, Living Reviews in Solar Physics, 9, 3 Yashiro, S., Gopalswamy, N., Michalek, G., et al. 2004, Journal of Geophysical Research (Space Physics), 109, A07105 20 Part III Publications 21 DECLARATION Wydziałl Fizyki, Astronomii i Informatyki Stosowanej Uniwersytet Jagiello´nski O´swiadczenie Ja, ni˙zej podpisana: Anitha Ravishankar (nr indeksu: 1138767), doktorantka Wydziałlu Fizyki, Astronomii i Informatyki Stosowanej Uniwersytetu Jagiello´nskiego, o´swiadczam, ˙ze przedłlo˙zona przeze mnie rozprawa doktorska pt. Study of coronal mass ejections (CMEs) using STEREO and SOHO observation jest oryginalna i przedstawia wyniki bada´n wykonanych przeze mnie osobi´scie, pod kierunkiem dra hab. Grzegorza Michałlka. Prace napisałlam samodzielnie. O´swiadczam, ˙ze moja rozprawa doktorska zostałla opracowana zgodnie z Ustawa o prawie autorskim i prawach pokrewnych z dnia 4 lutego 1994 r. (Dziennik Ustaw 1994 nr 24 poz. 83 wraz z p´o´zniejszymi zmianami). Jestem ´swiadoma, ˙ze niezgodno´s´c niniejszego o´swiadczenia z prawda ujawniona w dowolnym czasie, niezale˙znie od skutk´ow prawnych wynikajacych z ww. ustawy, mo˙ze spowodowa´c uniewa˙znienie stopnia nabytego na podstawie tej pracy. Anitha Ravishankar Krak´ow, 20.12.2020 85