ST1.10

We present the first statistical analysis of complexity changes affecting the magnetic structure of interplanetary coronal mass ejections (ICMEs), with the aim of answering the following questions: how frequently do ICMEs undergo magnetic complexity changes during propagation? What are the causes of such changes? Do the in situ properties of ICMEs differ depending on whether they exhibit complexity changes? 

We consider multi-spacecraft observations of 31 ICMEs carried out by MESSENGER, Venus Express, ACE, and STEREO between 2008 and 2014 during periods of radial alignment. By analyzing their magnetic properties at the inner and outer observing spacecraft, we identify complexity changes which manifest as fundamental alterations in the ICME magnetic topology, or as significant re-orientations of the ICME magnetic structure. Plasma and suprathermal electron data at 1 au, as well as simulations of the ambient solar wind enable us to reconstruct the propagation scenario for each event, and to identify critical factors controlling their evolution. 

Results show that 65% of ICMEs change their complexity between Mercury and 1 au, and that the interaction with multiple large-scale solar wind structures is the main driver of these changes. Furthermore, 71% of ICMEs observed at large radial (>0.4 au) but small longitudinal (<15 degrees) separations exhibit complexity changes, indicating that the propagation over large distances strongly affects ICMEs. Results also suggest ICMEs may be magnetically coherent over angular scales of at least 15 degrees, supporting earlier theoretical and observational estimates. This work provides statistical evidence that magnetic complexity changes are consequences of ICME interactions with large-scale solar wind structures, rather than intrinsic to ICME evolution, and that such changes are only partly identifiable from in situ measurements at 1 au.

How to cite: Scolini, C., Winslow, R. M., Lugaz, N., Salman, T. M., Davies, E. E., and Galvin, A. B.: Magnetic complexity changes within interplanetary coronal mass ejections: insights from a statistical study based on radially-aligned spacecraft observations, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2833, https://doi.org/10.5194/egusphere-egu22-2833, 2022.

The interaction of interplanetary coronal mass ejections (ICMEs) and stream interaction regions (SIRs) gives rise to complex heliospheric plasma and magnetic field conditions. Considering the different magnetic configurations of both phenomena as well as the source regions in the solar corona, there is also the possibility of magnetic reconnection either at coronal heights or farther out in the heliosphere.

The event of February 7th, 2014 shows clear signatures of a qualitative alteration of the ICME structure in ACE plasma and magnetic field data. There is a significant drop of the magnetic field strength inside the FR simultaneously to an enhancement in temperature and a high variability of speed. The flow angle reversal expected to take place at the stream interface sharply coincides with the onset of the ICME magnetic field rotations and drop of temperature below expected temperature. The speed inside the flux rope, yet showing the aforementioned variations, overall features a decline from the front to the rear of the ICME. The launch site of the ICME is derived from SDO AIA data, showing its location to be 30° West from a N-S elongated coronal hole.

These results imply a deterioration of the FR due to magnetic reconnection, either caused by the proximity of CH and CME eruption site and favorable magnetic configurations, or the heliospheric interaction of the associated SIR and ICME. WSA-ENLIL simulations suggest that the ICME catches up with the SIR close to Earth, which, along with the in-situ signatures, implies the simultaneous occurrence of stream interface and flux rope onset. The declining speed profile that is characteristic for quiescent ICME spatial evolution suggests no high-speed stream is inhibiting expansion from behind. Due to its complexity, this event provides a great opportunity to study the interaction of ICMEs and SIRs.

How to cite: Geyer, P., Dumbovic, M., and Temmer, M.: Case study of interacting large-scale solar wind phenomena in the heliosphere, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5063, https://doi.org/10.5194/egusphere-egu22-5063, 2022.

The orbit of the Parker Solar Probe (PSP) during the 5th encounter with the Sun presented an opportunity for a multi-observation analysis including the observations of Sun-Earth Connection Coronal and Heliospheric Investigation (SECCHI) coronagraphs and Large Angle and Spectrometric Coronagraph (LASCO) coronagraphs. Streamer-blowout coronal mass ejections (SBO-CMEs) are the dominant CME population during solar minimum. With the aid of extrapolated coronal fields and remote observations of the off-limb low corona, we study the initiation of an SBO-CME preceded by consecutive CME eruptions following a multi-stage sympathetic breakout scenario. The suprathermal electron pitch-angle distributions (PADs) and magnetic field observations by PSP suggest that draping of interplanetary magnetic field lines about the CME caused a curvature in the adjacent heliospheric current sheet, initiated magnetic reconnection with the CME flux rope about ~45 hours before it encountered PSP, and eroded ~38% of its initial poloidal magnetic flux at ~0.5 AU. This study covering inner heliospheric observation and analysis of SBO-CME magnetic content provides important implications for the origin of twisted magnetic field lines in SBO-CME flux ropes as the flux rope is not perturbed much by the interplanetary propagation. Also, the multi-spacecraft observations allowed us to estimate the distances where reconnection between the flux rope and its surroundings may be initiated. 

How to cite: Pal, S., Kilpua, E., Good, S., Lynch, B., Palmerio, E., Asvestari, E., Pomoell, J., and Stevens, M.: Eruption and Interplanetary Evolution of a Stealth Streamer-blowout CME Observed at ~0.5 AU, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5544, https://doi.org/10.5194/egusphere-egu22-5544, 2022.

We present a catalogue of 35 interplanetary coronal mass ejections (ICMEs) observed by the Juno spacecraft during its cruise phase to Jupiter in conjunction with at least one other spacecraft at heliocentric distances near or less than 1 AU (by MESSENGER, Venus Express, Wind, or STEREO). Previous ICME catalogues are used to find conjunctions between spacecraft, and events with magnetic field features that can be matched unambiguously across different spacecraft are selected. We conduct a multi-spacecraft analysis of ICME properties between 0.3 and 2.2 AU: we first investigate the global expansion of ICMEs by tracking the variation in magnetic field strength with increasing heliocentric distance of individual events, finding significant variability in magnetic field relationships for individual events in comparison with statistical trends. With the availability of plasma data at 1 AU, local and global expansion rates are compared; despite following expected trends, the local and global expansion rates are weakly correlated. Finally, for those events with clearly identifiable magnetic flux ropes, we investigate their magnetic complexity as they propagate; we find that 60% of events undergo at least one change in complexity between observations at the innermost spacecraft and Juno. The multi-spacecraft catalogue produced in this study provides a valuable link between ICME observations in the inner heliosphere and beyond 1 AU, contributing to our understanding of ICME evolution in situ. We intend the catalogue to be a useful resource for future studies of ICMEs and space weather research at Earth and other planets.

How to cite: Davies, E., Winslow, R., Scolini, C., Forsyth, R., and Möstl, C.: Multi-spacecraft Observations of Interplanetary Coronal Mass Ejections between 0.3 and 2.2 AU: Conjunctions with the Juno Spacecraft, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12423, https://doi.org/10.5194/egusphere-egu22-12423, 2022.

We present the results of a search for multipoint in situ and imaging observations of interplanetary coronal mass ejections (ICMEs) with the Heliophysics System Observatory, from 2020 April to present day. This builds up on our recent publication in ApJ Letters introducing the living ICME lineup catalog available at https://helioforecast.space/lineups. We highlight a few new lineup events captured by those spacecraft from September to November 2021, when all were located within 50 degrees east of the Sun-Earth line. Multi-messenger observations of ICME flux ropes and shocks are much needed to make progress on the understanding of the global magnetic configuration of ICMEs, space weather forecasting, the magnetic connectivity of the solar wind to the Sun and the propagation of solar energetic particles.

How to cite: Möstl, C., Weiss, A. J., Reiss, M. A., Amerstorfer, T., Bailey, R. L., Bauer, M., Barnes, D., Davies, J. A., Harrison, R. A., Davies, E. E., Heyner, D., Horbury, T. S., and Bale, S. D.: Multipoint Interplanetary Coronal Mass Ejections Observed with Solar Orbiter, BepiColombo, Parker Solar Probe, Wind, and STEREO-A, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1964, https://doi.org/10.5194/egusphere-egu22-1964, 2022.

Context. Late on 2013 August 19, a coronal mass ejection (CME) erupted from an active region located near the far-side central meridian from Earth’s perspective. The event and its accompanying shock were remotely observed by the STEREO-A, STEREO-B and SOHO spacecraft. The interplanetary (IP) counterpart (ICME) was intercepted by MESSENGER near 0.3 au, and by both STEREO-A and STEREO-B, near 1 au, which were separated by 78 degrees in heliolongitude.

Aims. The main objective of this study is to follow the radial and longitudinal evolution of the ICME throughout the inner heliosphere, and to examine possible scenarios for the different magnetic flux-rope (MFR) configuration observed on the solar disk, and measured in-situ at the locations of MESSENGER and STEREO-A, separated by 15 degrees in heliolongitude, and at STEREO-B, which detected the ICME flank.

Methods. Solar disk observations are used to estimate the ‘MFR type’, namely, the magnetic helicity, axis orientation and axial magnetic field direction of the MFR. The graduated cylindrical shell model is used to reconstruct the CME in the corona. The analysis of in-situ data, specifically, plasma and magnetic field, is used to estimate the global IP shock geometry and to derive the MFR type at different in-situ locations, which is compared to the type estimated from solar disk observations. The elliptical cylindrical analytical model is used for the in-situ MFR reconstruction.

Results. Based on the CME geometry and on the spacecraft configuration, we find that the MFR structure detected at STEREO-B belongs to the same ICME detected at MESSENGER and STEREO-A. The opposite helicity deduced at STEREO-B, might be due to the spacecraft intercepting one of the legs of the structure far from the MFR axis, while STEREO-A and MESSENGER are crossing through the core of the MFR. The different MFR orientations measured at MESSENGER and STEREO-A arise probably because the two spacecraft measure a curved, highly distorted and rather complex MFR topology. The ICME may have suffered additional distortion in its evolution in the inner heliosphere, such as the west flank is traveling faster than the east flank when arriving near 1 au.

How to cite: Rodríguez-García, L., Nieves-Chinchilla, T., Gómez-Herrero, R., Zouganelis, I., Vourlidas, A., Balmaceda, L., Dumbovic, M., Jian, L., Mays, L., Carcaboso, F., Guedes-Dos Santos, L. F., and Rodríguez-Pacheco, J.: Evidence of a complex structure within the 2013 August 19 coronal mass ejection. Radial and longitudinal evolution in the inner heliosphere, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1017, https://doi.org/10.5194/egusphere-egu22-1017, 2022.

High-resolution spectral diagnostic data gathered from the total solar eclipse in Neuquen, Argentina provided a rare glimpse of Fe X, XI, XIV ions approximately ~110 minues after the initial plasma eruption that led to a near side coronal mass ejection (CME). The iron ion spectral data represents equilibrium temperatures from 0.9 to 1.9 MK and lower Mg I prominences were also observed. We present a well constrained temperature map of both sides of the corona, where the CME occurred and opposite side which is relatively unperturbed.

A geometric simulation based upon Doppler mapping from our spectrometer, perpendicular motion from other cameras, and LASCO velocity estimates is utilized to find critical CME propagation parameters that extend from the low corona until secondary detection at several solar radii. This data fills the gap of spectral measurements from other space telescopes.

How to cite: Muro, G. and Morgan, H.: Post-CME spectroscopic observations during the 2020 total solar eclipse, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12699, https://doi.org/10.5194/egusphere-egu22-12699, 2022.

Heliospheric magnetic flux ropes (MFRs) are usually considered to be the magnetic structure that dominates the transport of mass and energy from the Sun into the heliosphere. They entrain a confined plasma within a helically organized magnetic topology, transporting magnetic flux and helicity into the heliosphere, as well as being the main driver of geomagnetic activity.

Following the methodology introduced by Florido-Llinas. et. al. (Sol. Phys. 295, 118, 2020) we carry out a further study to evaluate the effect of distortions in MFR stability in the heliosphere. This way, we gain an insight in the understanding of the dynamical processes ruling the propagation and evolution of MFRs in the interplanetary medium, in a view to improve our space weather forecasting capability.

How to cite: Capellas Coderque, S. and Nieves-Chinchilla, T.: Study of heliospheric magnetic flux rope instabilities driven by distortions, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-435, https://doi.org/10.5194/egusphere-egu22-435, 2022.

Heliospheric magnetic flux ropes (MFRs) are usually considered to be the magnetic structures in the solar wind confining plasma in a static or dynamic equilibria. They are also associated with the internal structure of the Coronal Mass Ejections (CMEs), the main drivers of geomagnetic activity. In the Heliosphere, MFRs can be described as straight axial-symmetric geometry with a variation with radius and angle of pressure and magnetic field.

Several missions such as STEREO or Solar Orbiter provide in-situ measurements of such magnetic structures. A well-known method to analyse them is the Grad-Shafranov reconstruction technique. In this article we provide a detailed overview, review of its variations and improvements and analysis of new events using this technique. Both quantitative and qualitative classification of such MFRs is done according to its orientation, shape and magnetic field and pressure profiles.

Based on the flux rope model described by Nieves-Chinchilla et al. (2018), we also investigate the physical characteristics and the underlying basic equilibrium state.

How to cite: Jumilla Lorenz, J. and Nieves-Chinchilla, T.: The Grad-Shafranov reconstruction technique: overview, improvements and analysis, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-437, https://doi.org/10.5194/egusphere-egu22-437, 2022.

One of the important challenges in the field of space weather study is to predict the arrival time of the shocks associated with the interplanetary coronal mass ejections (ICMEs). In many Sun-to-Earth magnetohydrodynamic (MHD) simulations, a numerical perturbation mimicking the initial stage of the CME/ICME event is given at a position of corresponding coronal event in a steady state of the solar corona and/or solar wind. Then, the temporal evolution of the perturbed solar corona and solar wind are simulated. The numerical perturbation is a critical component in this kind of CME simulation model.

Recently we have developed a new model suite combining our two existing MHD models, one is for the solar corona (Hayashi, 2005 ApJ 161:480) and the other is for solar wind (Wu+, 2012 Solar Physics 295:25; Wu+ 2020 JASTP 201:105211). In this model suite, plasma perturbations expressed with Gaussian spatial distribution and several parameters are given to initiate the CME/ICME simulation. For better simulating the Sun-Earth CME and ICME propagation, we made an iterative Newton-Raphson type minimization module for optimizing the perturbation parameters such that the differences in the CME speed within r < 30 Rsun and the arrival time of the CME-driven shocks at the Earth between the observation and simulation will be reduced simultaneously. We will report the results, in particular, which kinetic, thermal, and/or magnetic parameters are most important for numerically reproducing the ICMEs propagation from corona to 1 AU in this analysis study.

How to cite: Hayashi, K., Wu, C.-C., and Liou, K.: Optimization of parameters of CME initiation in the MHD simulation suite, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-899, https://doi.org/10.5194/egusphere-egu22-899, 2022.

Space weather has the difficult task to try to anticipate the propagation of eruptive events such as coronal mass ejections (CMEs) in order to assess their possible impact on the Earth’s space environment. This requires an accurate description of the background in which CMEs propagate, mainly the continuum ejecta of particles that is the solar wind and the dynamo-generated heliospheric magnetic field. This proves challenging as the solar wind and dynamo magnetic field are interacting with each other depending on the activity cycle of our star, both at large and small scales. To be able to model accurately such a wide variety of scales and parameter regimes, the approach used by the EUHFORIA 2.0 project is to use a chain of models, taking advantage of existing codes to combine their strengths through numerical coupling across the heliosphere. The first step of this chain is the data-driven modeling of the inner corona, from photosphere measurements up until 0.1 AU, and it proves especially critical as it serves as boundary condition for the rest of the models.

In that regard, we will present here two coronal MHD models implemented as an alternative to the semi-empirical WSA and SCS models used so far in EUHFORIA. By using the COOLFluiD framework, we developed a new coronal model with implicit solving methods and unstructured meshes, which proves faster than traditional explicit methods on regular grids. We used the coronal code Wind-Predict to benchmark this new model for the simple polytropic approximation in the first place, and we present the similarities and differences obtained for data-driven configurations and compare them with observations (white-light images, coronal hole boundaries, in-situ data at 1 AU after coupling with EUHFORIA). We then present the improvements foreseen for each codes, especially for the heating terms: Wind-Predict will incorporate self-consistent Alfvén waves while COOLFluiD will use ad-hoc heating terms and a multi-species treatment. We will finally discuss the implications for the coupling with EUHFORIA and the CME propagation between 0.1 and 1 AU.

This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 870405 (EUHFORIA 2.0) and the ESA project "Heliospheric modelling techniques“ (Contract No. 4000133080/20/NL/CRS).

How to cite: Perri, B., Leitner, P., Brchnelova, M., Baratashvili, T., Kuzma, B., Zhang, F., Lani, A., Poedts, S., Kochanov, A., Samara, E., Brun, A. S., and Strugarek, A.: Multi-ensemble MHD coronal modeling to improve background wind for CME propagation for EUHFORIA 2.0, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1124, https://doi.org/10.5194/egusphere-egu22-1124, 2022.

We present a comprehensive analysis of the three-dimensional magnetic flux rope structure generated during the Lynch et al. (2019, ApJ 880, 97) magnetohydrodynamic (MHD) simulation of a global-scale, 360 degree-wide streamer blowout coronal mass ejection (CME) eruption. We create both fixed and moving synthetic spacecraft to generate time series of the MHD variables through different regions of the flux rope CME. Our moving spacecraft trajectories are derived from the spatial coordinates of Parker Solar Probe’s past Encounters 7 and 9 and future Encounter 23. Each synthetic time series through the simulation flux rope ejecta is fit with three different in-situ flux rope models commonly used to characterize the large-scale, coherent magnetic field rotations observed in a significant subset of interplanetary CMEs (ICMEs). We present each of the in-situ flux rope model fits to the simulation data and discuss the similarities and differences in the model flux rope spatial orientations, field strengths, and magnetic flux content. We compare in-situ model properties to those calculated with the MHD data for both classic bipolar and unipolar ICME flux rope configurations as well as more problematic profiles such as those with a significant radial component to the flux rope axis orientation or profiles obtained with large impact parameters. We find general agreement among the in-situ flux rope fitting results for the classic profiles and much more variation among results for the problematic profiles. We also present a comparison between the MHD simulation data and the in-situ model flux ropes in a hodogram representation of the magnetic field rotation. We conclude that the in-situ flux rope models are generally a decent approximation to the field structure, but all the caveats associated with in-situ flux rope models will still apply (and perhaps moreso) at distances below 30Rs. We discuss our results in the context of future PSP observations of CMEs in the extended corona.

How to cite: Lynch, B., Al-Haddad, N., Yu, W., Palmerio, E., and Lugaz, N.: On the utility of flux rope models for CME magnetic structure below 30Rs, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6205, https://doi.org/10.5194/egusphere-egu22-6205, 2022.

Space weather forecasting requires precise estimation of the arrival time of eruptive events, which typically propagate through and interact with the solar atmosphere and solar wind. Therefore, the arrival time estimation depends on the accuracy of modelling the solar atmosphere and the complex interactions. For instance, the EUHFORIA 2.0 project expects an accurate and efficient coronal model that covers the region from the surface of the Sun up to 0.1AU, serving as the inner boundary condition for the heliospheric model.

Based on the open-source code COOLFluiD, we have developed a fully implicit MHD coronal model. The model has been validated by data-driven coronal simulations, and the fully implicit temporal solution significantly accelerates the numerical simulations. More physical mechanisms, e.g., the heating term(s), and numerical techniques, e.g., high-order schemes, are being developed to improve this model further. In this work, we specifically focus on the numerical flux schemes (Lax-Friedrichs, HLL, etc.) of the finite-volume MHD solver used by the coronal model, and evaluate their performance and impact on the coronal simulations. Both the internal structures and the quantities at the outer boundary are quantitatively compared.

This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 870405 (EUHFORIA 2.0).

How to cite: Zhang, F., Perri, B., Brchnelova, M., Baratashvili, T., Kuźma, B., Leitner, P., Lani, A., and Poedts, S.: Evaluations of Numerical Flux Schemes of a Coronal MHD Model, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6012, https://doi.org/10.5194/egusphere-egu22-6012, 2022.

Global magnetohydrodynamic (MHD) computational fluid dynamics (CFD) simulations have become an important tool for solar weather research. These simulations use solar magnetogram data to compute structures in the solar corona. We have developed one such model based on the COOLFLuiD platform and validated it through comparison with other state-of-art codes and observations (Leitner et al., 2022, submitted). Currently, further physics is added to the solver to move it from ideal MHD to full MHD, such as radiation, coronal heating or conduction. Description of this physics and its results is what is most usually discussed in papers concerning coronal MHD CFD. 

However, physics is only one part of the solution when CFD is used. Actually, it is the numerics that is oftentimes the limiting factor, setting constraints on the accuracy and speed of these solvers. Many different problems can arise due to the finite discretisation of the domain or even due to the solver working with simplified ideal MHD equations instead of the full ones. It is rarely discussed what type of a computational grid should be used depending on the type of the simulations at hand, and it is mentioned even less often what type of errors and inaccuracies such an inappropriate grid type can cause. An unsuitable grid can also cause convergence problems and decrease the speed of the solver considerably (Brchnelova et al., 2022, submitted).

In our work, we investigate the sources of inaccuracies and errors which can compromise the global coronal MHD CFD results. We have observed that due to the large ranges of density magnitudes involved, spurious numerical fluxes can result on mesh cell interfaces when these cells are either highly skewed or the boundaries otherwise non-orthogonal. These spurious fluxes can create local errors of up to 40% in the velocity field in the most deformed portions of the computational grid. Further inaccuracies were observed also in the sharpness of the resulting velocity structures, this time due to artificially generated electric fields during the simulation. 

Thus, in our talk, we will summarize the most important of the issues observed, their causes and potential means of their mitigation. For controlling the errors due to the spurious fluxes while simultaneously optimizing the performance of the solver, we will show a trade-off between different grid topologies and what to expect in the results. Similarly, to enhance the sharpness of the features, it will also be discussed how to mitigate the generation of artificial electric fields via careful formulation of the initial state and boundary conditions.

This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 870405 (EUHFORIA 2.0) and the ESA project "Heliospheric modelling techniques“ (Contract No. 4000133080/20/NL/CRS).

How to cite: Brchnelova, M., Zhang, F., Perri, B., Lani, A., and Poedts, S.: Of mesh artefacts and electric fields: the bane of numerical global coronal modelling, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12255, https://doi.org/10.5194/egusphere-egu22-12255, 2022.

How to cite: Maharana, A., Scolini, C., Schmiede, B., and Poedts, S.: Modelling CME rotation during propagation in the heliosphere with EUHFORIA, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5935, https://doi.org/10.5194/egusphere-egu22-5935, 2022.

Coronal mass ejections (CMEs) are one of the major sources for space weather disturbances. If the magnetic field inside an Earth-directed CME, or its associated sheath region, has a southward-directed north-south magnetic field component (Bz), then it interacts effectively with the Earth’s magnetosphere, leading to severe geomagnetic storms. Therefore, it is crucial to predict the strength and direction of Bz inside Earth-impacting interplanetary CMEs (ICMEs) in order to forecast their geo-effectiveness. Since the magnetic field of solar eruptions cannot reliably be measured via remote means, and direct continuous measurements of the Earth impacting solar transients are routinely available only very close to our planet, modelling of magnetic properties is paramount. The state-of-the art global heliospheric MHD models typically use the spheromak to characterize the magnetic structure of a CME and simulate its evolution from Sun-to-Earth. However, recent studies (Asvestari et al. 2021) have reported that the spheromak tends to rotate due to its interaction with the ambient medium, posing a great challenge in space weather forecasting.  

In this work, we study the spheromak rotation by modelling a realistic CME event on 2013 April 11 using the “European heliospheric forecasting information asset” (EUHFORIA). We found that when using the default density value in EUHFORIA, the axis of symmetry of the spheromak undergoes approximately 90 degrees of rotation and nearly aligns to the propagation direction of the CME. However, if we constrain the spheromak density using the observational data, we find an order of magnitude higher density value as compared to the default one. Interestingly, the spheromak rotation is observed to be reduced for higher densities. However, we note that the high-density spheromaks undergo significant compression as compared to the low-density ones. Using the observationally constrained density values, we obtain good agreement between the model result and in-situ observation. The simulation is also able to capture the overall magnetic structure of the associated sheath region ahead of the CME flux rope. These results are promising towards forecasting of Bz in near real time inside both ICME and sheath regions.  

This research has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 870405 (EUHFORIA 2.0). 

How to cite: Sarkar, R., Pomoell, J., Kilpua, E., Asvestari, E., Wijsen, N., Maharana, A., and Poedts, S.: Studying the spheromak rotation for realistic CME modelling with EUHFORIA and its dependency on initial model parameters, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11208, https://doi.org/10.5194/egusphere-egu22-11208, 2022.