## Session 4 - The role of Interplanetary Coronal Mass Ejections in Space Weather

Luciano Rodriguez (ROB); Sergio Dasso (IAFE/UBA)
Tuesday 28/11, 9:45 - 13:00
Delvaux

KEYWORDS - ICME, Interplanetary Coronal Mass Ejections, space weather, in situ data

Interplanetary Coronal Mass Ejections (ICMEs) are the main drivers of large geomagnetic storms. Their influence on space weather is a topic of intense research. In recent years, multispacecraft observations and high performance numerical MHD simulations have contributed largely to this field. The comparisons between models and observations are clarifying several problems, such as the effects of the ambient solar wind on their propagation and internal configuration, the link between ICMEs and non-thermal energetic particles in the heliosphere (solar, interplanetary, and galactic origin), etc. In this session we invite contributions focused on ICME studies, including ICME propagation in the heliosphere, the interaction of ICMEs with Earth and/or with other planets, the link between CMEs and ICMEs, their relation with energetic particles, as well as on other general topics linked with ICMEs.

Poster Viewing
From Monday noon to Wednesday morning

Talks
Tuesday November 28, 09:45 - 11:00, Delvaux
Tuesday November 28, 11:45 - 13:00, Delvaux

### Talks : Time schedule

Tuesday November 28, 09:45 - 11:00, Delvaux
 09:45 EUHFORIA: Current Status and Path Towards Modeling the Evolution of the Magnetic Structure of Coronal Mass Ejections Pomoell, J et al. Invited Oral Jens Pomoell[1], Christine Verbeke[2], Eleanna Asvestari[1], Camilla Scolini[2,3], Stefaan Poedts[2], Emilia Kilpua[1], Manuela Temmer[4], Nicolas Wijsen[2], Erkka Lumme[1], Alexey Isavnin[1], Erika Palmerio[1], Jasmina Magdalenic[3] [1]University of Helsinki, Finland; [2]KU Leuven, Leuven, Belgium; [3]Royal Observatory of Belgium, Belgium; [4]University of Graz, Austria Unraveling the formation and evolution of coronal mass ejections (CMEs) from the Sun to Earth remains one of the outstanding goals in current solar-terrestrial physics and space weather research. In particular, capturing the dynamical evolution of the magnetic field configuration of CMEs from initiation to in-situ detection is of key importance in order to advance the accuracy of predictions of geo-effectiveness. Providing accurate and routine modeling of the Sun-to-Earth evolution of flux rope CMEs using EUHFORIA is the main focus of the current development effort of the model. EUHFORIA is a magnetohydrodynamics model that computes the dynamics in the inner heliosphere from 0.1 AU up to the orbit of Mars. The model uses data-driven methodologies relying mainly on photospheric magnetograms and coronagraph observations to capture the dynamic solar wind including coronal mass ejections. In this work, the current status of EUHFORIA is presented. In addition, we highlight on-going work to advance beyond the baseline in the modeling pipeline. In particular, the path towards using magnetized CMEs in the model is discussed. 10:15 Probabilistic model for heliospheric propagation of Interplanetary Coronal Mass Ejections: Drag-based ensemble model (DBEM) Dumbovic, M et al. Oral Mateja Dumbovic[1], Jasa Calogovic[2], Bojan Vrsnak[2], Manuela Temmer[1], Astrid Veronig[1], Leila M. Mays[3] [1]Kanzelhöhe Observatory-IGAM, Institute of Physics, University of Graz; [2]Hvar Observatory, Faculty of Geodesy, University of Zagreb; [3]NASA Goddard Space Flight Center The drag-based model (DBM) for heliospheric propagation of ICMEs is a widely used simple analytical model which can predict ICME arrival time and speed at a given heliospheric distance (Vršnak et al., 2013, SolPhys). It is based on the assumption that the heliospheric propagation of ICMEs, is solely under the influence of MHD drag, where ICME propagation is determined based on CME properties as well as the properties of the ambient solar wind. The current version of the DBM is operational as part of ESA’s SSA programme (http://swe.ssa.esa.int/web/guest/graz-dbm-federated). The DBM takes into account the ICME geometry to track the whole leading edge of an ICME, and can estimate whether or not an ICME will reach the observer, and if, when and at what impact speed. However, there is a lack of uncertainty estimation for a single event, which can be established using an ensemble modeling approach. We present a newly developed Drag-Based Ensemble Model (DBEM) which takes into account the uncertainties of observation-based model input by making an ensemble, i.e. sets of n CME observations and m synthetic measurements of ambient solar wind speed and drag parameter. Using multiple model runs with different input parameters, DBEM calculates a distribution of predicted arrival times and speeds allowing to forecast the confidence in the likelihood of the ICME arrival. 10:30 Forecasting the arrival time of the CME’s shock at the Earth Paouris, E et al. Oral Evangelos Paouris, Helen Mavromichalaki Faculty of Physics, National and Kapodistrian University of Athens A new model obtained from an extended study of the ICME’s properties and applied for the estimation of the arrival time of the CME’s associated shock at the Earth, is presented. This model is based on the Effective Acceleration Model-EAM (Paouris and Mavromichalaki, Solar Physics, 2017) where the acceleration of the CME is calculated by its initial speed, as it is observed by LASCO/SOHO coronagraphs and then taking into account the distance of the Earth from the Sun, the arrival time of the shock as well as the velocity of the CME at L1 (v), are calculated. This technique has been applied to selected events of the last time period and the results are discussed. It is already used by the Athens Space Weather Forecasting Center of the University of Athens for the forecasting of the geomagnetic conditions useful for the issued daily space weather report. This model is also available to the CME scoreboard at the Community Coordinated Modeling Center – CCMC for comparison with other related models. 10:45 Observations and Simulations of the Sun to Earth Evolution of a STEREO-Era Set of Earth-Impacting CMEs and their In Situ Magnetic Field Kay, C et al. Oral Christina Kay, Nat Gopalswamy NASA Goddard Space Flight Center Code 671 Coronal mass ejections (CMEs) drive extreme space weather events throughout the solar system. Predicting the effects of a CME impact requires knowing not only if a CME will impact a given point, but also which part of the CME impacts, and what its magnetic properties are upon impact. We explore the relation between CME deflections and rotations, which change the position and orientation of a CME, and the resulting magnetic profiles at 1 AU. For 45 STEREO-era, Earth-impacting CMEs, we determine the region from which each CME erupts, reconstruct its coronal position and orientation, and perform a ForeCAT (Kay et al. 2015) simulation of the coronal deflection and rotation. From this large set of reconstructed and modeled CME deflections and rotations, we determine variations in the behavior over the solar cycle as well as correlations with CME properties. We then couple the ForeCAT results with the FIDO in situ magnetic field model (Kay et al. 2017), allowing for comparisons with ACE and Wind observations. FIDO successfully reproduces the in situ magnetic field for all but three of the CMEs. From random walk best fits, we distinguish between ForeCAT's ability to determine FIDO's input parameters, and the limitations of using a simple flux rope model to reproduce complicated in situ structures. We find that the FIDO results are quite sensitive to changes of order a degree in the CME latitude, longitude, and tilt, suggesting that accurate space weather predictions require accurate measurements of a CME's position and orientation.

Tuesday November 28, 11:45 - 13:00, Delvaux
 1 Magnetic clouds and their driven shocks/sheaths near Earth: geoeffective properties studied with a superposed epoch technique Dasso, S et al. e-Poster Sergio Dasso[1,2], Jimmy Joel Masías-Meza[1], Pascal Demoulín[3], Luciano Rodríguez[4], and Miho Janvier[5] [1]Universidad de Buenos Aires, Buenos Aires, Argentina; [2]CONICET – Universidad de Buenos Aires. Instituto de Astronomía y Física del Espacio (IAFE), Buenos Aires, Argentina; [3]Observatoire de Paris, Meudon Principal Cedex, France; [4]Royal Observatory of Belgium, Brussels, Belgium; [5]Institut d’Astrophysique Spatiale, Orsay Cedex, France Magnetic Clouds (MCs) are huge interplanetary manifestations of solar eruptions. When MCs travel faster than the surrounding solar wind, the overtaken interplanetary plasma forms a sheath of heated and compressed plasma at their front. The main aim of this work is to find which are the common plasma and magnetic properties present in (and around) MCs observed near Earth. We apply a superposed epoch method to a large set of MCs observed in situ by the spacecraft ACE. We find that slow MCs at 1 AU have on average sheaths that are more massive, and we conclude that the low bulk speed of these events is mainly due to the drag (then MCs slow down during their travel from the Sun) and not due to their initial conditions near the corona. Furthermore, we find that slow MCs also have a more symmetric magnetic field profile and that their sheaths are in a self-similar expansion as the associated MC. In contrast, fast MCs have an asymmetric magnetic profile and a sheath in compression. In all the types of MCs, we find that the proton density, the temperature, and the magnetic fluctuations present in the sheath can diffuse within the front of the MC; we propose that this is a consequence of magnetic reconnection. The obtained typical profiles of sheath and MC properties corresponding to slow, middle, and fast structures, can be used for forecasting or modelling these events. They are also useful for improving future operative space weather activities. 2 Quantification of solar wind parameters from measurments by SOHO and DSCOVR spacecrafts during series of Interplanetary Coronal Mass Ejections in the helioactive period September 2-15, 2017 Mishev, A et al. e-Poster Yordan Tassev[1], Peter I.Y. Velinov[1], Dimitrinka Tomova[2], Alexander Mishev[3,4] [1]Institute for Space Research and Technology Bulgarian Academy of Sciences Sofia, Bulgaria; [2]Sofia University “St. Kliment Ohridski” Faculty of Mathematics and Informatics Sofia, Bulgaria; [3]Space Climate Research Unit, University of Oulu, Finland; [4]Sodankyla Geophysical Observatory (Oulu unit), University of Oulu, Finland Serie of Interplanetary Coronal Mass Ejections (ICMEs) during extreme solar activity in early September 2017 at minimum of solar cycle 24 is analized. The origin of the intensive solar-terrestrial disturbances was the Active Region AR2673, which produced four powerful eruptions, including the strongest flare X9.3 of Solar Cycle 24 on September 6, 2017, after which began G4 - Severe geomagnetic storm on 07-08.09.2017 with Ap = 106, and also - the second strongest flare X8.2 of Solar Cycle 24 on September 10, 2017, which produced ground level enhancement of cosmic rays (GLE72). Calculations of the solar wind parameters from measurments by SOHO and DSCOVR spacecrafts in the point of Lagrange L1 between Sun and Earth (0.99 AU) are made: the kinetic (dynamic) energy density Ek, thermal energy density Et and magnetic energy density Em during the investigated period September 2-15, 2017. We found a specific distribution of the solar wind energies during and after the ICMEs. It is likely that both kinetic and magnetic energies can be used as predictors of strong geomagnetic storms. 3 Multipoint, galactic cosmic ray observations associated with a series of interplanetary coronal mass ejections: the case study of June 2015 Papaioannou, A et al. e-Poster A. Papaioannou[1], B. Heber[2], A. Anastasidis[1], A. Belov[3], K. Herbst[2], E. Eroshenko[3], A. Abunin[3], M. Abunina[3] [1]Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing (IAASARS), National Observatory of Athens, I. Metaxa & Vas. Pavlou St., GR-15236, Penteli, Greece; [2]Christian-Albrechts-Universitaet zu Kiel, Leibnizstrasse 11, 24118 Kiel, Germany; [3]Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN), 42092 Troitsk, Moscow Region, Russia Galactic cosmic rays (GCRs) fill the interplanetary (IP) space and have an important role in our understanding of the heliospheric environment. In this work, we compare, multipoint space-based and ground based GCR data to explore structures in the IP space. In particular, we look for correlations between the GCR time series observed from the Electron Proton Helium INstrument (EPHIN) aboard the SOHO and neutron monitors (NMs) on the ground. We analyze the period of June 2015 during which a sequence of coronal mass ejections (CMEs) and their corresponding interplanetary counterparts (ICMEs) fill the IP space. Those drive shocks that clearly affect the distributions of GCRs resulting to a large Forbush decrease (FD). We employ in-situ plasma and particle data as well as ground based NM measurements and we discuss the efficiency of the series of the ICMEs in modulating the GCRs. 4 Galactic cosmic rays and Forbush decreases at Mars: comparison of measurement by MAVEN in orbit and by MSL on ground Guo, J et al. e-Poster Jingnan Guo[1], Niklas Lundt[1], Rob Lillis[2], Robert F. Wimmer-Schweingruber[1], Donald M. Hassler[3], Christina Lee[2], Henning Lohf[1], Arik Posner[4], Cary Zeitlin[5] [1]University of Kiel; [2]Space Science Laboratory, University of California, Berkeley, USA; [3]Southwest Research Institute, Boulder, CO, USA; [4]NASA Headquarters, Science Mission Directorate, Washington DC, USA; [5]Leidos, Houston, Texas, USA The Radiation Assessment Detector (RAD), on board Mars Science Laboratory’s (MSL) rover Curiosity, has been measuring the ground level particle fluxes along with the radiation dose rate at the surface of Mars since August 2012. Similar to neutron monitors at Earth, RAD sees many Forbush decreases (FDs) in the galactic cosmic ray (GCR) induced surface fluxes and dose rates. These FDs are associated with coronal mass ejections (CMEs) and/or streaming/corotating interaction regions (SIRs/CIRs). On top of the Martian atmosphere, the solar energetic particle (SEP) instrument aboard of the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft orbiting Mars has also been detecting particle fluxes including both SEPs and GCRs and the high energy flux channel can also be employed to detect FDs. For the first time, we study the statistics and properties of a list of FDs observed in-situ at Mars, both on the surface seen by MSL/RAD and at the orbit detected by MAVEN/SEP. These measurements of the FD magnitudes both at ground and in orbit agree with simulation results. The consistent difference between the magnitudes of the FDs within and outside the Martian atmosphere can be attributed to energy-dependent modulation of GCR particles by both the Martian atmosphere and the varying levels of solar activity. 5 Sun-to-Earth simulations of geo-effective coronal mass ejections with EUHFORIA: A heliospheric-magnetospheric model chain approach Scolini, C et al. p-Poster Camilla Scolini[1,2], Christine Verbeke[1], Stefaan Poedts[1], Luciano Rodriguez[2], Jens Pomoell[3], William D. Cramer[4], Joachim Raeder[4], Nat Gopalswamy[5] [1]KU Leuven, Leuven, Belgium; [2]SIDC, Royal Observatory of Belgium, Uccle, Belgium; [3]University of Helsinki, Helsinki, Finland; [4]Space Science Center, University of New Hampshire, NH, USA; [5]NASA GSFC, Greenbelt, MD, USA Coronal Mass Ejections (CMEs) and their interplanetary counterparts are considered to be the major space weather drivers. An accurate modelling of their onset and propagation up to 1 AU represents a key issue for more reliable space weather forecasts, and predictions about their actual geo-effectiveness can be performed by coupling global heliospheric models to 3D models describing the terrestrial environment. In this work we perform a Sun-to-Earth comprehensive analysis of the July 12, 2012 CME with the aim of testing the space weather predictive capabilities of the newly developed EUHFORIA heliospheric model integrated with a flux-rope CME model. In order to achieve this goal, we make use of a model chain approach by using EUHFORIA outputs at Earth as input parameters for the OpenGGCM magnetospheric model. We first reconstruct the CME kinematic parameters by means of single- and multi- spacecraft reconstruction methods based on coronagraphic and heliospheric CME observations. The magnetic field-related parameters of the flux rope are estimated based on imaging observations of the photospheric and low coronal source regions of the eruption. We then simulate the event with EUHFORIA, testing the effect of the flux-rope CME model compared to the cone CME model, on simulation results at L1. We compare simulation outputs with in-situ measurements of the Interplanetary CME and we use them as input for the OpenGGCM model, so to investigate the magnetospheric response to solar perturbations. From simulation outputs we extract some global geomagnetic activity indexes and compare them with actual data records and with results obtained by the use of empirical relations. Finally, we discuss the forecasting capabilities of such kind of approach and its future improvements. 6 Modelling coronal mass ejections with EUHFORIA: Testing the effect of different shapes on predictions at 1 AU Scolini, C et al. p-Poster Camilla Scolini[1,2], Christine Verbeke[1], Stefaan Poedts[1], Jens Pomoell[3] [1]KU Leuven, Leuven, Belgium; [2]SIDC, Royal Observatory of Belgium, Uccle, Belgium; [3]University of Helsinki, Helsinki, Finland Coronal Mass Ejections (CMEs) and their interplanetary counterparts are considered to be the major space weather drivers, and an accurate modelling of their onset and propagation up to 1 AU represents a key issue for more reliable space weather forecasts. In this work we use the newly developed EUHFORIA 3D MHD heliospheric code to test the effect of different CME shapes, all based on a spherical or quasi-spherical geometry, on simulation results at different spacecraft locations at 1 AU. We take as case study an artificial CME launched on June 6, 2008, corresponding to a period of quiet solar wind conditions near Earth. We run several simulations testing different implementations of the cone model, all assuming a spherical or quasi-spherical CME shape but using different relations to define the inner boundary shape as well as the CME radius and insertion profile in the heliospheric domain. Our analysis indicates that all these parameters significantly affect simulation results, both in terms of the resulting global CME shape once inserted in the heliosphere, as well as in terms of the predicted in-situ plasma properties at 1 AU. We discuss the implication of such effects on space weather predictions, with the aim of bringing to the attention of the community the role such details may play on space weather forecasting operations. 7 Determination of diffusion coefficients of cosmic rays in the inner heliosphere Masías meza, J et al. p-Poster Jimmy Masías-Meza[1],Sergio Dasso[2] [1]Instituto de Astronomía y Física del Espacio (UBA-CONICET), Buenos Aires, Argentina; [2]Departamento de Ciencias de la Atmósfera y los Océanos (FCEN-UBA), Buenos Aires, Argentina One of the most important processes in the transport of Galactic Cosmic Rays (GCRs) is the spatial diffusion due to the presence of magnetic irregularities in the medium. In order to characterize quantitatively these processes, we perform test-particle simulations with an in-house C++ code, to calculate the mean free paths associated to spatial diffusion in the turbulent interplanetary medium. We present some verifications of our code, and present results on the determination of the GCR mean free paths as a function of the radial distance to the Sun inside the heliosphere. 8 LISA-like missions for possible space weather applications Benella, S et al. p-Poster Simone Benella University of Urbino "Carlo Bo" and National Institute for Nuclear Physics, Florence LISA Pathfinder was the mission of the European Space Agency devoted to the testing of the technology that will be placed aboard the first interferometer for gravitational wave detection in space: LISA. Second and third generation interferometers may consist of constellations of several LISA-like instruments. Diagnostics detectors devoted to the control of the environment on these satellites include particle detectors and magnetometers. The integral galactic cosmic-ray flux measured aboard LISA Pathfinder in L1 from February 18th 2016 to July 18th 2017 indicates that decreases of the cosmic-ray flux may be correlated to the transit of interplanetary magnetic structures resulting at the origin of geomagnetic storms of different intensity. The occurrence of these depressions, in case of near-real time downlink, may be used to generate alerts for geomagnetic activity. In particular, the effects of a non-recurrent Forbush decrease associated with an ICME transit on August 2nd 2016 is discussed in detail. Periodicities of recurrent galactic cosmic-ray depressions observed aboard LISA Pathfinder are also investigated with the Empirical Mode Decomposition (EMD) method. 9 Accurate estimation of the near-Sun magnetic field of coronal mass ejections Moraitis, K et al. p-Poster Kostas Moraitis[1], Etienne Pariat[1], Antonia Savcheva[2] [1]LESIA, Observatoire de Paris; [2]Harvard-Smithsonian Center for Astrophysics The geoeffectiveness of a Coronal Mass Ejection (CME) is related to the properties of its magnetic field. The proper estimation of the CME magnetic field intensity is thus crucial to space weather. One of the methods to estimate the CME magnetic field is based on magnetic helicity and its conservation property. The accuracy of the determined CME magnetic field depends then on the accurate knowledge of the value of helicity in the CME source region. The estimation of relative magnetic helicity in an active region is optimally computed in the spherical geometry, the natural coordinate system for the Sun. We present here the first method that properly computes relative magnetic helicity in spherical coordinates. The volumes considered (in the low corona) are wedge-shaped and the three-dimensional magnetic field is considered known there. The method is first tested with well-known semi-analytic force-free solutions for the magnetic field. Then, it is applied to nonlinear force-free reconstructions of the magnetic field of a solar active region, where a flux-rope is first inserted and then it is relaxed magnetofrictionally to force-free state. From the change in helicity during the evolution of the eruption, the CME magnetic field is deduced and then it is compared with the known characteristics of the inserted flux rope. We find that the improved helicity calculation method has the potential to lead to proper estimations of the near-Sun CME magnetic field. 10 First-principles simulations of magnetic reconnection within the solar environment Boella, E et al. p-Poster E. Boella, D. Gonzalez-Herrero, M. E. Innocenti and G. Lapenta Centre for mathematical Plasma Astrophysics, KU Leuven, Celestijnenlaan 200B, 3001 Leuven, Belgium Fully understanding magnetic reconnection in the solar corona constitutes a fundamental step towards the correct modeling and subsequent forecasting of space weather events relevant for Earth. Kinetic simulations are essential in advancing our comprehension of a phenomenon whose macroevolution is determined by tiny microscopic scales \cite{Bemporad}. Their importance is even more significant considering the fact that no direct observations are possible since the intrinsic scales of reconnection are smaller than the resolution of the current instruments. The Particle-In-Cell (PIC) method \cite{PIC}, due to the reduced number of physical approximation, is the perfect tool to perform first-principles simulations of magnetic reconnection in the solar corona. However, as it models physics at a microscopic level, it is computationally demanding, especially when the aim is to study a process like reconnection, which spans over a multitude of time and spatial scales. Very recently, we have developed an efficient new PIC algorithm, which has been proven to be tremendously stable and accurate over a wide range of temporal and spatial resolutions \cite{Lapenta}, thus enabling the first (to the authors' knowledge) realistic three-dimensional kinetic simulations of magnetic reconnection in the solar corona. In this talk, we are going to describe the main steps that led to this great breakthrough and report the implementation of the method on a new massively parallel three-dimensional PIC code, called ECsim \cite{Lapenta2}. The new approach is then used to model realistic reconnection events in the solar environment, considering a large domain sufficient to describe the interaction of large scale dynamics with microscopic processes. In particular, the evolution of a macroscopic current sheet, with width much larger than the ion skin depth, is investigated, proving the occurrence of fractal reconnection \cite{Taijima}. Results show the formation of magnetic islands of smaller sizes at different spatial scales inside the macroscopic current sheet leading to turbulent reconnection and thus providing a possible explanation about the difference between the much bigger observed and theoretically estimated thickness of current sheets in the solar corona. \begin{thebibliography}{99} \bibitem{Bemporad} A. Bemporad, Astrophys. J. \textbf{689}, 572 (2008). \bibitem{PIC} \vspace{-8pt} J. M. Dawson, Rev. Mod. Phys. \textbf{55}, 403, (1983); C. K. Birsdall and A. B. Langdon, \textit{Plasma physics via computer simulation}, McGraw-Hill Book Company, 1985; R. Hockney and J. Eastwood, \textit{Computer simulation using particles}, Taylor and Francis, 1988. \bibitem{Lapenta}\vspace{-8pt} G. Lapenta, J. Comput. Phys. \textbf{334}, 349 (2017). \bibitem{Lapenta2}\vspace{-8pt} G. Lapenta, D. Gonzalez-Herrero and E. Boella, J. Plasma Phys. \textbf{83} (2017). \bibitem{Taijima}\vspace{-8pt} T. Taijima and K. Shibata, \textit{Plasma Astrophysics}, Reading: Addison-Wesley (1997). \end{thebibliography} 11 Comparison between EUHFORIA and ENLIL: CME on September 4, 2010 Mierla, M et al. p-Poster Marilena Mierla[1,2], Camilla Scolini[3], Leila Mays[4], Jens Pomoell[5], Luciano Rodriguez[1] [1]Royal Observatory of Belgium, Brussels, Belgium; [2]Institute of Geodynamics of the Romanian Academy, Bucharest, Romania; [3]Center for mathematical Plasma Astrophysics, KU Leuven, Belgium; [4]NASA/GSFC, USA; [5]University of Helsinki, Department of Physics, Finland In this study we aim to compare two CME propagation MHD codes (ENLIL, Odstrcil et al. 1999 and EUHFORIA, Pomoell et al. 2017) by applying them to the same coronal mass ejection (CME) of September 4, 2010. The CME could be followed all the way from the Sun to the STEREO-A spacecraft, where it arrived on September 7, 2010. Comparison of the results obtained with the two models is presented. 12 Analysis of the magnetic field fluctuations during a substorm Kozak, L et al. p-Poster Liudmyla Kozak[1,2], Bogdan Petrenko[1], Elena Kronberg[3], Elena Grigorenko[4], Antony Lui[5], Andrew Prokhorenkov[1] [1]Kyiv Taras Shevchenko University, Kyiv, Ukraine; [2]Space Research Institute National Academy of Sciences of Ukraine and State Space Agency of Ukraine, Kyiv, Ukraine; [3]Max Planck Institute for Solar System Research, Göttingen, Germany; [4]Space Research Institute, Russian Academy of Sciences, Moscow, Russia; [5]Applied Physics Laboratory, Laurel, Maryland, United States The Earth’s magnetosphere is the nonlinear dynamical system, which shows a complex behavior in response to the changes of the solar wind conditions. One of the major displays of the magnetospheric dynamics is a substorm. Turbulence is the natural state of the hydrodynamic flows and cosmic plasma; therefore, studying its characteristics is essential for the understanding of the fundamental properties of nature. In magnetohydrodynamics, the properties of turbulence can be dramatically affected both by flow boundaries and the scales of the structures (waves, vortices, etc.) formed by magnetic and electric fields. The turbulence of plasma flows can be generated by many classes of instabilities: drift dissipative, kinetic, magnetohydrodynamic, etc. In addition, the turbulence is characterized by a large number of degrees of freedom and nonlinearly interacting modes. Scientists typically use statistical physics and the theory of probability to describe such a medium. This way they can obtain information about average variations in the macroscopic parameters of the plasma medium in time (or space) without scrutinizing the conditions of excitation of specific nonlinear processes. In this work, we address the features of turbulent processes in the magnetospheric tail. We analyzed the properties of the small-scale turbulence in the near Earth environment. We use measurements of the space mission Cluster, spacecraft 2 with time resolution 22,5 Hz during magnetic field dipolarization for the analysis of turbulent processes in the tail of the Earth's magnetosphere. We consider four events (17.10.2005, 20.07.2013, 12.08.2014, 12.09.2015). In the frame of the investigation fractal and multifractal research methods were supplemented with spectral and wavelet analysis. In particular, we have carried out the following: analysis of tails and evolution on different scale of the probability density function of magnetic field fluctuations (fractal analysis); Determination of excess and analysis of expanded self-similarity ESS-analysis (multifractal analysis); Spectral power density analysis (spectral studies); Amplitude analysis and wavelet power spectra of the signal (wavelet analysis). The work is done in the frame of the grant Az. 90 312 from the Volkswagen Foundation («VW-Stiftung»). 13 Validation of Drag-Based Ensemble Model (DBEM): probabilistic model for heliospheric propagation of CMEs Calogovic, J et al. p-Poster Jaša Čalogović[1], Mateja Dumbović[2], Bojan Vršnak[1], Manuela Temmer[2], Leila M. Mays[3], Astrid Veronig[2] [1]Hvar Observatory, Faculty of Geodesy, Kačićeva 26, HR-10000 Zagreb, Croatia; [2]Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz, Austria; [3]Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD, USA The Drag-based Model (DBM) is a simple empirical model for heliospheric propagation of Coronal Mass Ejections (CMEs). It is based on the equation of motion that depends on the CME launch speed, background solar wind speed and CME mass and density (gamma parameter). The model predicts the CME arrival time and speed at Earth or any other targets in the solar system. However, the main problem of empirical and numerical models (e.g. ENLIL) is the lack of reliable observations that are needed for the model input. This can induce a large error in the CME arrival time (−1.7 $\pm$ 18.3 h; Vršnak et al., 2014) when observations and DBM forecasts are compared. The main advantage of DBM is its very fast computational time (<< 1s). This allows an ensemble modeling approach to provide a probabilistic forecasting of CME arrival time and speed within several minutes compared to numerical models that would need several hours (e.g., ENLIL). The Drag-Based Ensemble Model (DBEM) takes into account the variability of model input parameters by making an ensemble of n different input parameters to calculate a distribution and significance of DBM results. Using such approach DBEM can determine most likely CME arrival times and speeds, quantify the prediction uncertainties and calculate the forecast confidence intervals. We present the DBEM output and compare it to the observed ICME arrival times at Earth as well as to the numerical ENLIL model output using the list of ICME events.