FRiED : A Novel Three-dimensional Model of Coronal Mass Ejections

We present a novel three-dimensional (3D) model of coronal mass ejections (CMEs) that unifies all key evolutionary aspects of CMEs and encapsulates their 3D magnetic field configuration. This fully analytic model is capable of reproducing the global geometrical shape of a CME with all major deformations taken into account, i.e., deflection, rotation, expansion, “pancaking,” front flattening, and rotational skew. Encapsulation of 3D magnetic structure allows the model to reproduce in-situ measurements of magnetic field for trajectories of spacecraft-CME encounters of any degree of complexity. As such, the model can be used single-handedly for the consistent analysis of both remote and in-situ observations of CMEs at any heliocentric distance. We demonstrate the latter by successfully applying the model for the analysis of two CMEs.Peer reviewe

Three-dimensional evolution of flux rope CMEs and its relation to the local orientation of the heliospheric current sheet

Flux ropes (FRs) ejected from the Sun may change their geometrical orientation during their evolution which directly affects their geoeffectiveness. Therefore, it is crucial to understand how solar FRs evolve in the heliosphere to improve our space weather forecasting tools. We analyze 15 coronal mass ejections (CMEs), with clear FR signatures, observed during the decay of Solar Cycle 23 and rise of Solar Cycle 24. We estimate initial orientations of the FRs at the origin using extreme ultraviolet observations of post-eruption arcades and/or eruptive prominences. Then we reconstruct multiviewpoint coronagraph observations of the CMEs from ~2 to 30 Rs with a three-dimensional geometric representation of a FR to determine their geometrical parameters. Finally, we propagate the FRs from ~30 Rs to 1 AU through MHD-simulated background solar wind while using in-situ measurements at 1 AU of the associated magnetic cloud as a constraint for the propagation technique. These methodology allows us to estimate the FR orientation all the way from the Sun to 1 AU. We find that while the FRs deflection occurs predominantly below 30 Rs, a significant amount of deflection and rotation happens between 30 Rs and 1 AU. We compare the FR orientation to the local orientation of the heliospheric current sheet (HCS). We find that slow FRs tend to align with the streams of slow solar wind in the inner heliosphere. During the solar cycle minimum the slow solar wind channel as well as the HCS usually occupy the area in the vicinity of the solar equatorial plane, which in the past led researchers to the hypothesis that FRs align with the HCS. Our results show that exclusions from this rule are explained by interaction with the Parker-spiralled background magnetic field, which dominates over the magnetic interaction with the HCS in the inner heliosphere at least during solar minimum conditions.Comment: 19 pages, 7 figures, 1 table, accepted for publication in Solar Physic

Grad–Shafranov Reconstruction of Magnetic Clouds: Overview and Improvements

The Grad–Shafranov reconstruction is a method of estimating the orientation (invariant axis) and cross section of magnetic flux ropes using the data from a single spacecraft. It can be applied to various magnetic structures such as magnetic clouds (MCs) and flux ropes embedded in the magnetopause and in the solar wind. We develop a number of improvements of this technique and show some examples of the reconstruction procedure of interplanetary coronal mass ejections (ICMEs) observed at 1 AU by the STEREO, Wind, and ACE spacecraft during the minimum following Solar Cycle 23. The analysis is conducted not only for ideal localized ICME events but also for non-trivial cases of magnetic clouds in fast solar wind. The Grad–Shafranov reconstruction gives reasonable results for the sample events, although it possesses certain limitations, which need to be taken into account during the interpretation of the model results.Peer reviewe

ElEvoHI : A NOVEL CME PREDICTION TOOL FOR HELIOSPHERIC IMAGING COMBINING AN ELLIPTICAL FRONT WITH DRAG-BASED MODEL FITTING

This article has an erratum: DOI 10.3847/0004-637X/831/2/210In this study, we present a new method for forecasting arrival times and speeds of coronal mass ejections (CMEs) at any location in the inner heliosphere. This new approach enables the adoption of a highly flexible geometrical shape for the CME front with an adjustable CME angular width and an adjustable radius of curvature of its leading edge, i.e., the assumed geometry is elliptical. Using, as input, Solar TErrestrial RElations Observatory (STEREO) heliospheric imager (HI) observations, a new elliptic conversion (ElCon) method is introduced and combined with the use of drag-based model (DBM) fitting to quantify the deceleration or acceleration experienced by CMEs during propagation. The result is then used as input for the Ellipse Evolution Model (ElEvo). Together, ElCon, DBM fitting, and ElEvo form the novel ElEvoHI forecasting utility. To demonstrate the applicability of ElEvoHI, we forecast the arrival times and speeds of 21 CMEs remotely observed from STEREO/HI and compare them to in situ arrival times and speeds at 1 AU. Compared to the commonly used STEREO/HI fitting techniques (Fixed-phi, Harmonic Mean, and Self-similar Expansion fitting), ElEvoHI improves the arrival time forecast by about 2 to +/- 6.5 hr and the arrival speed forecast by approximate to 250 to +/- 53 km s(-1), depending on the ellipse aspect ratio assumed. In particular, the remarkable improvement of the arrival speed prediction is potentially beneficial for predicting geomagnetic storm strength at Earth.Peer reviewe

Advancing In Situ Modeling of ICMEs: New Techniques for New Observations

It is generally known that multi-spacecraft observations of interplanetary coronal mass ejections (ICMEs) more clearly reveal their three-dimensional structure than do observations made by a single spacecraft. The launch of the STEREO twin observatories in October 2006 has greatly increased the number of multipoint studies of ICMEs in the literature, but this field is still in its infancy. To date, most studies continue to use on flux rope models that rely on single track observations through a vast, multi-faceted structure, which oversimplifies the problem and often hinders interpretation of the large-scale geometry, especially for cases in which one spacecraft observes a flux rope, while another does not. In order to tackle these complex problems, new modeling techniques are required. We describe these new techniques and analyze two ICMEs observed at the twin STEREO spacecraft on 22-23 May 2007, when the spacecraft were separated by ~8 degrees. We find a combination of non-force-free flux rope multi-spacecraft modeling, together with a new non-flux rope ICME plasma flow deflection model, better constrains the large-scale structure of these ICMEs. We also introduce a new spatial mapping technique that allows us to put multispacecraft observations and the new ICME model results in context with the convecting solar wind. What is distinctly different about this analysis is that it reveals aspects of ICME geometry and dynamics in a far more visually intuitive way than previously accomplished. In the case of the 22-23 May ICMEs, the analysis facilitates a more physical understanding of ICME large-scale structure, the location and geometry of flux rope sub-structures within these ICMEs, and their dynamic interaction with the ambient solar wind

Deflection and Rotation of CMEs from Active Region 11158

Between the 13 and 16 of February 2011 a series of coronal mass ejections (CMEs) erupted from multiple polarity inversion lines within active region 11158. For seven of these CMEs we use the Graduated Cylindrical Shell (GCS) flux rope model to determine the CME trajectory using both Solar Terrestrial Relations Observatory (STEREO) extreme ultraviolet (EUV) and coronagraph images. We then use the Forecasting a CME's Altered Trajectory (ForeCAT) model for nonradial CME dynamics driven by magnetic forces, to simulate the deflection and rotation of the seven CMEs. We find good agreement between the ForeCAT results and the reconstructed CME positions and orientations. The CME deflections range in magnitude between 10 degrees and 30 degrees. All CMEs deflect to the north but we find variations in the direction of the longitudinal deflection. The rotations range between 5\mydeg and 50\mydeg with both clockwise and counterclockwise rotations occurring. Three of the CMEs begin with initial positions within 2 degrees of one another. These three CMEs all deflect primarily northward, with some minor eastward deflection, and rotate counterclockwise. Their final positions and orientations, however, respectively differ by 20 degrees and 30 degrees. This variation in deflection and rotation results from differences in the CME expansion and radial propagation close to the Sun, as well as the CME mass. Ultimately, only one of these seven CMEs yielded discernible in situ signatures near Earth, despite the active region facing near Earth throughout the eruptions. We suggest that the differences in the deflection and rotation of the CMEs can explain whether each CME impacted or missed the Earth.Comment: 18 pages, 6 figures, accepted in Solar Physic

Flux ropes in space plasmas

A lot of modern ground-based and space systems, such as navigation satellites, electric power grids, and telecommunication frameworks, can be affected by the changes in the near-Earth space environment, i.e., space weather. The main driver of the space weather is the Sun, which provides a supersonic flow of plasma, known as the solar wind. Coronal mass ejections (CMEs) are the most prominent feature of solar activity. They result from the eruptions on the Sun and propagate almost radially from it embedded into the solar wind. CMEs drive the strongest disturbances of the near-Earth space environment and cause the strongest geomagnetic storms when they encounter the magnetosphere of the Earth. A significant fraction of CMEs exhibit a specific configuration of twisted magnetic field lines, i.e., the flux rope configuration. The geoffectiveness of flux rope CMEs depends on their internal magnetic structure, morphological properties, speed, and the geometry of their propagation through the interplanetary space. In this thesis, the internal structure of flux rope CMEs and their three-dimensional evolution in the interplanetary space were investigated using the combination of white-light and extreme ultraviolet observations and in-situ measurements and modeling. The results of the analysis show that a typical flux rope CME consists of regions of physically different plasma with the flux rope occupying one of them. The methodology for studying the evolution of the individual flux rope in three-dimensional space is described. The presented technique is used to show that solar flux ropes experience significant deflections and rotations during their propagation from the Sun to the Earth's orbit that have to be taken into account for reliable space weather forecasting. These structures deflect predominantly towards the solar equatorial plane and their rotations are affected by the solar wind streams. It is discovered that 40% of the flux rope evolution happens after 30 solar radii. Flux-rope-like structures can also form in the magnetosphere during the periods of geomagnetic disturbances. They are generated in the magnetotail configurations with multiple reconnection sites and travel towards the Earth or away from it. Both types of these helical magnetic structures are addressed in this thesis as well. It is demonstrated that the properties of these structures help to get insight into the dynamics of the magnetosphere. The model of evolution of earthward-traveling flux ropes is presented, according to which they deteriorate and degrade into dipolarization fronts, another magnetic field configuration that is characteristic for geomagnetic disturbances. This thesis contributes both to the improvement of the flux rope analysis techniques as well as conducts a comprehensive analysis of solar and magnetospheric flux ropes and their evolution. The results of the research advance our understanding of the Sun-Earth coupling in one dynamical process and can be used for improving the space weather forecasting tools.Maan lähiavaruuden eli avaruussään muutokset voivat vaikuttaa moniin nykyaikaisiin maanpäällisiin ja avaruudessa toimiviin järjestelmiin, kuten navigointisatelliitteihin, sähköverkkoihin ja televiestintäjärjestelmiin. Avaruussään liikkeellepaneva voima on aurinko, josta on peräisin ääntä nopeampi plasmavirta, joka tunnetaan aurinkotuulena. Koronan massapurkaukset (CME) ovat auringon toiminnan näkyvimpiä piirteitä. Ne ovat peräisin auringossa tapahtuvista tulivuoren purkauksista, ja siitä ne leviävät lähes säteittäin aurinkotuuleen sulautuneena. Koronan massapurkaukset ovat syynä lähiavaruuden suurimpiin häiriöihin, ja ne aiheuttavat suurimmat geomagneettiset myrskyt joutuessaan maan magnetosfääriin. Suuressa osassa koronan massapurkauksia on erityinen kiertyneiden magneettikenttäviivojen konfiguraatio eli vuoköysien konfiguraatio. Vuoköyden koronan massapurkausten geotehokkuus riippuu niiden sisäisestä magneettirakenteesta, morfologisista ominaisuuksista, nopeudesta ja niiden planeettojen välisen etenemisen geometriasta. Tässä opinnäytetyössä tutkittiin vuoköyden koronan massapurkausten sisäistä rakennetta ja niiden kolmiulotteista kehittymistä planeettojen välisessä tilassa käyttämällä valkeaa valoa ja äärimmäistä ultraviolettivaloa koskevia havaintoja ja itse kohteessa tehtyjä mittauksia ja mallintamista. Analyysin tulokset osoittavat, että tyypillinen vuoköyden koronan massapurkaus koostuu fyysisesti erilaisen plasman alueista, joista yhtä vuoköysi käyttää. Työssä kuvataan menetelmä, jolla tutkitaan yksittäisen vuoköyden kehittymistä kolmiulotteisessa tilassa. Esitettyä tekniikkaa käytetään osoittamaan, että auringon vuoköydet taipuvat ja kiertyvät huomattavasti edetessään auringosta maan kiertoradalle, mikä on otettava huomioon luotettavassa aurinkosään ennustamisessa. Nämä rakenteet taipuvat pääasiassa kohti auringon ekvaattoritasoa, ja aurinkotuulivirrat vaikuttavat niiden kiertymisiin. On havaittu, että 40 prosenttia vuoköyden kehittymisestä tapahtuu 30 auringonsäteen jälkeen. Vuoköyden kaltaiset rakenteet voivat myös muodostua magnetosfäärissä geomagneettisten häiriöjaksojen aikana. Ne kehittyvät magneettisen pyrstön konfiguraatioissa, joissa on monia uudelleenliitäntäkohtia, ja kulkevat kohti maata tai siitä poispäin. Tässä työssä käsitellään myös näitä molempia magneettisia kierrerakenteita. Siinä osoitetaan, että näiden rakenteiden ominaisuudet auttavat ymmärtämään magnetosfäärin dynamiikkaa. Siinä esitetään maata kohti kulkevien vuoköysien kehittymisen malli, jonka mukaan ne heikkenevät ja hajoavat dipolarisaatiorintamiksi, jotka ovat toinen geomagneettiselle häiriölle ominainen magneettikenttäkonfiguraatio. Tämä työ edistää vuoköyden analyysitekniikoiden parantamista, ja lisäksi siinä tehdään kattava analyysi auringon ja magnetosfäärin vuoköysistä ja niiden kehittymisestä. Tutkimuksen tulokset auttavat meitä ymmärtämään paremmin auringon ja maan välistä yhteyttä yhdessä dynaamisessa prosessissa, ja sitä voidaan käyttää parantamaan aurinkosään ennustustyökaluja

How Many CMEs Have Flux Ropes? Deciphering the Signatures of Shocks, Flux Ropes, and Prominences in Coronagraph Observations of CMEs

We intend to provide a comprehensive answer to the question on whether all Coronal Mass Ejections (CMEs) have flux rope structure. To achieve this, we present a synthesis of the LASCO CME observations over the last sixteen years, assisted by 3D MHD simulations of the breakout model, EUV and coronagraphic observations from STEREO and SDO, and statistics from a revised LASCO CME database. We argue that the bright loop often seen as the CME leading edge is the result of pileup at the boundary of the erupting flux rope irrespective of whether a cavity or, more generally, a 3-part CME can be identified. Based on our previous work on white light shock detection and supported by the MHD simulations, we identify a new type of morphology, the `two-front' morphology. It consists of a faint front followed by diffuse emission and the bright loop-like CME leading edge. We show that the faint front is caused by density compression at a wave (or possibly shock) front driven by the CME. We also present high-detailed multi-wavelength EUV observations that clarify the relative positioning of the prominence at the bottom of a coronal cavity with clear flux rope structure. Finally, we visually check the full LASCO CME database for flux rope structures. In the process, we classify the events into two clear flux rope classes (`3-part', `Loop'), jets and outflows (no clear structure). We find that at least 40% of the observed CMEs have clear flux rope structures. We propose a new definition for flux rope CMEs (FR-CMEs) as a coherent magnetic, twist-carrying coronal structure with angular width of at least 40 deg and able to reach beyond 10 Rsun which erupts on a time scale of a few minutes to several hours. We conclude that flux ropes are a common occurrence in CMEs and pose a challenge for future studies to identify CMEs that are clearly not FR-CMEs.Comment: 26 pages, 9 figs, to be published in Solar Physics Topical Issue "Flux Rope Structure of CMEs

THE ANALYSIS OF TRENDS FOR THE INTRODUCTION OF PROCESS MANAGEMENT IN RUSSIAN AND WESTERN CORPORATIONS

Enterprises that introduce and develop process management systems need to analyze current trends in domestic and foreign enterprises. This article summarizes the research results of leading Western and Russian consulting organizations on the main trends in the application of process management methodologies: Lean Production, Six Sigma, Lean Production + Six Sigma, Rummler-Branch, Hammer, SCOR, BPTrends Associates, CMMI; and software-embedded methodologies. About half of Western companies systematically carry out activities to update and develop process management. 50% of respondents called value chain modeling an important task; 30% - measurement of the parameters of the main processes, training of managers and the use of process information by managers; and 40% - automation of key business processes. The most important tasks of Russian enterprises are also documentation (79%), standardization (40%), optimization (42%), and automation (46%) of business processes. The analysis carried out in the article allows us to talk about an increase in the interest of Russian and Western corporations in process management technologies, their more active application for the development of enterprises. Under these conditions, the analysis of the trends of process management, the goals of introducing the process approach and the regularity of the implementation of the main activities of the process development gain their relevance. The authors give their interpretation of the obtained results, as well as formulate conclusions