ST1.6 | Observing and Modelling the Solar Wind and CMEs Through the Heliosphere
Observing and Modelling the Solar Wind and CMEs Through the Heliosphere
Including ST Division Outstanding Early Career Scientist Award Lecture
Convener: Rui Pinto | Co-conveners: David BarnesECSECS, Erika PalmerioECSECS
Orals
| Fri, 28 Apr, 08:30–12:30 (CEST)
 
Room 1.14
Posters on site
| Attendance Thu, 27 Apr, 14:00–15:45 (CEST)
 
Hall X4
Posters virtual
| Attendance Thu, 27 Apr, 14:00–15:45 (CEST)
 
vHall ST/PS
Orals |
Fri, 08:30
Thu, 14:00
Thu, 14:00
The solar wind is a continuous plasma flow that fills the heliosphere and is crossed by strong transient perturbations such as interplanetary shocks, coronal mass ejections (CMEs), and (corotating) stream interaction regions (SIRs). These phenomena are capable of driving large disturbances at Earth as well as at the other planets. Understanding their physical behaviour and making accurate predictions about their properties and evolution is a difficult and ongoing issue in heliophysics. Remote-sensing and in-situ measurements from multiple vantage points, combined with ground-based observations and modelling efforts, are employed to study the solar wind plasma and CMEs from their onset to their arrival at planets and spacecraft throughout the heliosphere.

Recently launched spacecraft (including Parker Solar Probe, Solar Orbiter, and BepiColombo), “older” existing probes (such as STEREO and the assets near Earth and Mars), as well as planned and future missions present an ideal opportunity to test, validate and refine current knowledge in this field. We therefore encourage submissions with the aim of exploiting the latest observational and modelling efforts regarding CME and solar wind evolution during their propagation throughout the heliosphere. Contributions on novel methodologies and/or mission concepts that may help shed light on withstanding questions on the matter are also welcome.

Orals: Fri, 28 Apr | Room 1.14

Chairpersons: David Barnes, Erika Palmerio, Rui Pinto
08:30–08:35
08:35–09:05
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EGU23-8687
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ECS
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solicited
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ST Division Outstanding Early Career Scientist Award Lecture
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On-site presentation
Stephan G. Heinemann

Coronal holes (CH) are large, long-lived structures commonly observed in the solar corona as regions of reduced emission in EUV and X-ray wavelengths. They feature a characteristic open magnetic field configuration along which ionized electrons and atoms are accelerated into the interplanetary space. The resulting outflowing plasma is called high seed solar wind stream (HSS; see Cranmer 2009 and references therein). These HSSs are the major cause of minor to moderate geomagnetic activity at Earth (see Richardson 2018 and references therein).

To be able to predict the arrival and impact of those disturbances accurately, their origin and evolution need to be studied in detail. And to do so, it is imperative that CHs are accurately and reliably extracted, thus leading to the development of the Collection of Analysis Tools for Coronal Holes (CATCH). By using the intensity gradient across the CH boundary, it is possible to robustly extract CHs whose properties can then be analyzed. We find that the area of long-living CHs generally evolves by growing to a maximum before decaying. However, the associated magnetic field does not evolve equally. Depending on the CH, we find a correlation, an anti-correlation or even no correlation over the course of its lifetime. Therefore, we believe that the evolution of a CHs magnetic field is primarily driven by the large-scale connectivity changes in the Sun's global magnetic field. Further, we find that the plasma properties within CHs show a significant center to boundary gradient, which may justify the distance-to-boundary parameter used in some solar wind modeling.

To study the evolution of CHs in detail, a 360° view of the Sun is necessary; however, the magnetic far-side of the Sun still eludes. The few snapshots with Solar Orbiter provide only a fragmented picture of the magnetic field on the solar far-side. We found that by using EUV observations of the transition region (specifically using Stereo) it is possible to estimate the magnetic field density of CHs on the solar far side. In addition, we are currently investigating the incorporation of helioseismic observations into synoptic magnetograms to generate a maps that show the magnetic field of the whole Sun at a given time.

How to cite: Heinemann, S. G.: On the evolutionary aspects of solar coronal holes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8687, https://doi.org/10.5194/egusphere-egu23-8687, 2023.

09:05–09:25
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EGU23-7312
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solicited
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Virtual presentation
Peter Wyper

Decades of observations have revealed that Coronal Mass Ejections (CMEs) come in a variety of forms. Some have a classic 3-part structure, whilst others can be fan shaped or jet-like. Some of these differences can be put down to projection effects, but differences in magnetic structure also play a key role. Observational and simulation studies are now highlighting that the path by which a CME flux rope traverses the solar corona, and in particular the magnetic structures it interacts with on the way, shape the ultimate characteristics of the CME further out in the heliosphere. Therefore, understanding the nature of CME flux rope interaction with the ambient corona is a key part of predicting their evolution through the heliosphere and ultimately their geoeffectiveness at Earth. In this talk I’ll discuss from a modelling perspective some recent efforts to understand this interaction process and what it tells us about CMEs on a range of scales.

How to cite: Wyper, P.: What impact does the pathway through the solar corona make on CMEs?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7312, https://doi.org/10.5194/egusphere-egu23-7312, 2023.

09:25–09:35
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EGU23-7061
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On-site presentation
Christian Möstl, Ute Amerstorfer, Hannah T. Rüdisser, Andreas J. Weiss, Tanja Amerstorfer, Maike Bauer, Emma E. Davies, Rachel L. Bailey, and Martin A. Reiss

The problem of forecasting southward pointing magnetic fields in coronal mass ejections (CMEs) is closely tied to our ability to measure their magnetic field configuration between the Sun and 1 AU. I will review some of the ideas that have been developed to tackle this problem, from using solar proxies, heliospheric images, Faraday rotation and measuring the in situ magnetic field near the Sun Earth-line. Another way to make progress is to use the L1 data as boundary conditions for fast ensemble simulations, focusing on the flux rope parts inside CMEs. However, for any type of modeling and forecasting we need to better understand the global magnetic structure and shape of CME flux ropes from multi-spacecraft observations, now delivered by spacecraft such as Parker Solar Probe, Solar Orbiter, BepiColombo, STEREO-Ahead and Wind, ACE or DSCOVR. In the future, the PUNCH mission will allow for the first time to extract 3D information from heliospheric images, forming another trailblazer towards developing models for ESA's Vigil mission, and setting the stage for possible interplanetary fleets of small spacecraft.



How to cite: Möstl, C., Amerstorfer, U., Rüdisser, H. T., Weiss, A. J., Amerstorfer, T., Bauer, M., Davies, E. E., Bailey, R. L., and Reiss, M. A.: Forecasting southward pointing magnetic fields in solar coronal mass ejections, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7061, https://doi.org/10.5194/egusphere-egu23-7061, 2023.

09:35–09:45
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EGU23-9944
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On-site presentation
Jasmina Magdalenic, Senthamizh Pavai Valliappan, and Luciano Rodriguez

Observations of the solar wind at the close to the Sun distances by the Parker Solar Probe (PSP) show most of the time very strongly variable solar wind plasma characteristics. Inspecting the PSP observations during first ten perihelion, together with this large variability, we have also found a significant number of intervals of enhanced solar wind velocity appearing simultaneously with the decrease of the solar wind density, which indicates that this solar wind is originating from the coronal holes. However, out of thirty such intervals only few of them show velocity above 500 km/s. Majority of the identified wind flows have velocity of only about 400 km/s indicating that this solar wind will not be clearly distinguished as a flow when observed at 1 au distances. Employing the magnetic connectivity tool (developed by ESA’s MADAWG group) to associate the solar wind observed by the PSP with their source regions on the Sun, we identified the sources of that enhanced solar wind observed by the PSP to be the small coronal holes.

In this study we present the characteristics of a solar wind flows originating from such small coronal holes at close to the Sun distances and compare them with the characteristics of the fast solar wind originating from the large coronal holes. We also discuss on the possible reasons why we do not find more intervals of the fast solar wind in the PSP observations and compare the characteristics of solar wind observed at close to the Sun distances and at 1 au.

How to cite: Magdalenic, J., Valliappan, S. P., and Rodriguez, L.: Solar wind originating from the small coronal holes , EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9944, https://doi.org/10.5194/egusphere-egu23-9944, 2023.

09:45–09:55
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EGU23-5740
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On-site presentation
Ravindra Desai, Gordon Koehn, Emma Davies, Robert Forsyth, Jonathan Eastwood, and Stefaan Poedts

Coronal mass ejections (CMEs) are the largest type of eruption seen on our Sun and the primary cause of geomagnetic disturbances and storms when they arrive at the Earth. Most geomagnetic storms are created by the impact of single CME yet in a significant fraction of cases they are caused by the interaction of multiple CMEs or CMEs with other transient phenomena. In this paper we implement a spheromak CME description within our 3-D heliospheric MHD model and self-consistently model their interactions with the pre-existing solar wind and with one another. We assess their geo-effectiveness at 1 AU through quantification of the relevant solar wind variables and an empirical measures based upon solar wind-magnetosphere coupling functions. We show how the orientation and handedness of a given CME can have a significant impact on its geoeffectivness due to a prolonged conservation of toroidal flux caused by differential interplay with the Parker Spiral, and how a large range of possible CME-CME interactions can produce a diverse range of geophysical impacts at the Earth.

How to cite: Desai, R., Koehn, G., Davies, E., Forsyth, R., Eastwood, J., and Poedts, S.: Successive interacting coronal mass ejections: Preconditioning, magnetic reconnection and flux erosion: How to create a perfect storm?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5740, https://doi.org/10.5194/egusphere-egu23-5740, 2023.

09:55–10:05
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EGU23-7508
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ECS
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On-site presentation
Camilla Scolini, Noé Lugaz, Réka Winslow, and Charles Farrugia

Our knowledge of the physical processes carrying information across Coronal Mass Ejections (CMEs), thereby controlling the way CME structures respond to external disturbances  in interplanetary space, is still incomplete. One prominent question is whether CMEs are “coherent” structures, i.e. potentially capable of responding in a uniform manner to external forces, and across what (macroscopic) spatial scales does such coherence exist. A necessary condition for different regions within a given CME to exhibit a coherent behavior is that they must be causally connected to the perturbation source. Past studies suggested interplanetary CMEs may behave as coherent structures only locally, and indicated that the spatial scale of coherence may be hampered by interactions with large-scale structures in the solar wind. Additionally, observational studies often assumed the correlation in the magnetic field profiles at different spacecraft locations as a proxy for coherence, but the physical link between correlation and coherence is still to be established. Characterizing the physical mechanisms mediating CME structural changes in different solar wind conditions at a fundamental level is therefore imperative to better understand their evolution and impact on space-borne and ground-based anthropic activities. 

In this study, we investigate the role of Alfvénic fluctuations (AFs) as mediators of coherence within interplanetary CMEs, and the physical relationship between correlation and coherence using multi-point observations near 1 au. In order to determine if and to what extent AFs alter CMEs at different spatial scales, we compare CME signatures at multiple spacecraft in terms of presence/absence of AFs, AF properties (if present), and correlation of magnetic signatures.  We contextualize the results in terms of the CME interaction history and the causal connection of different spacecraft observations. This study reveals how AFs affect the correlation of CME magnetic signatures across different spatial scales, and helps reconcile correlation scales within CMEs with their coherent behavior. 

How to cite: Scolini, C., Lugaz, N., Winslow, R., and Farrugia, C.: Multi-point Investigation of CME Alfvénicity and Coherence near 1 au, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7508, https://doi.org/10.5194/egusphere-egu23-7508, 2023.

10:05–10:15
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EGU23-3579
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ECS
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On-site presentation
Tinatin Baratashvili, Benjamin Grison, Brigitte Schmieder, and Stefaan Poedts

Coronal Mass Ejections (CMEs) are the main drivers of interplanetary shocks and space weather disturbances. Strong CMEs directed towards Earth can have a severe impact on our planet and their timely prediction can enable us to mitigate (part of) the damage they cause. One of the key parameters that determine the geo-effectiveness of a CME is its internal magnetic configuration.

The novel heliospheric wind and CME propagation model Icarus (Verbeke et al. 2022) which is implemented within the framework of MPI-AMRVAC (Xia et al., 2018) introduces new capabilities for better and faster space weather forecasts. Advanced numerical techniques, such as solution adaptive mesh refinement (AMR) and radial grid stretching are implemented. The different refinement and coarsening conditions and thresholds are controlled by the user. These techniques result in optimized computer memory usage and a significant execution speed-up, which is crucial for forecasting purposes. 

In this study we validate a new magnetized CME model in Icarus by simulating  interplanetary coronal mass ejections (ICMEs).  We chose particular CME events observed at different radial distances from the Sun by MESSENGER and ACE. We aim to model two CME events, to examine the capabilities of the model in different configurations. We identify the originating active region for the CME of interest, reconstruct its characteristic parameters and initiate the CME propagation inside Icarus with a spheromak CME model. We focus on estimating the accuracy of the arrival time, the shock strength and the magnetic field components of the CME model in Icarus. Using observations of different satellites we can track the propagation of the CMEs in the heliospheric domain and assess the accuracy of the model at different locations.

Different AMR criteria are used to achieve higher spatial resolutions at propagating shock fronts and in the interiors of the ICMEs. This way the complex structure of the magnetic field and the deformation and (plasma and magnetic flux) erosion can be simulated with higher accuracy due to the advantage of AMR. Higher resolution is especially important for the spheromak model, because the internal magnetic field configuration affects the CME evolution and its interaction with the magnetized heliospheric wind significantly. We assess the capabilities of AMR at different locations in Icarus. Finally, the obtained synthetic time-series of plasma quantities at different satellite locations are compared to the available observational data. As a result, Icarus allows us to model CMEs with higher accuracy, yet efficiently.

TB acknowledges support from the European Union’s Horizon 2020 research and innovation program under No 870405 (EUHFORIA 2.0) and the ESA project “Heliospheric modeling techniques” (Contact No. 4000133080/20/NL/CRS).

How to cite: Baratashvili, T., Grison, B., Schmieder, B., and Poedts, S.: Validation of the magnetized ICME model with a multi-spacecradt study in Icarus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3579, https://doi.org/10.5194/egusphere-egu23-3579, 2023.

Coffee break
Chairpersons: Erika Palmerio, David Barnes, Rui Pinto
10:45–10:55
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EGU23-8506
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ECS
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On-site presentation
Andreas Wagner, Emilia K. J. Kilpua, Daniel J. Price, Jens Pomoell, Stefaan Poedts, Slava Bourgeois, Anshu Kumari, Farhad Daei, and Ranadeep Sarkar

Data-driven coronal models are attracting increasing attention for their ability to accurately capture the pre-eruption magnetic field configuration of active regions. However, the degree to which the current modelling techniques are able to provide information on the loss of stability and initial dynamics of the eruptions remains unclear. An interesting avenue for probing this is by employing time-dependent modelling such that the dynamic data-driving is switched-off at a given time. In this study, we investigate what we can learn from this relaxation procedure about the eruption itself and the instability that ultimately triggers it for at least two different active regions. To this effect, we use the time-dependent data-driven magnetofrictional model (TMFM) and perform multiple runs with varying relaxation times (i.e., time instances when the driving is switched off). Furthermore, we use two different physical models to simulate the coronal evolution after this point in time: the standard magnetofrictional method and a zero-beta MHD (magnetohydrodynamics) approach. In case of an eruption being triggered, the detailed evolution is characterised by tracking the associated magnetic flux rope which is extracted from the simulation data with a semi-automatic extraction algorithm. This flux rope detection and tracking procedure makes use of the twist number Tw, as well as the morphological gradient. For a further improvement of the extraction procedure, various mathematical morphology algorithms are performed to accurately extract the flux rope field lines. The properties of the extracted flux ropes are compared against their observational low-coronal manifestation in SDO/AIA data. 

How to cite: Wagner, A., Kilpua, E. K. J., Price, D. J., Pomoell, J., Poedts, S., Bourgeois, S., Kumari, A., Daei, F., and Sarkar, R.: Investigating Flux Rope Eruptivity via Time-dependent Data-driven Modelling, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8506, https://doi.org/10.5194/egusphere-egu23-8506, 2023.

10:55–11:05
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EGU23-4488
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On-site presentation
The Miniaturized Electron Proton Telescope, MERiT onboard Lunar Gateway
(withdrawn)
Shri Kanekal and the The Miniaturized Electron Proton Telescope
11:05–11:15
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EGU23-3444
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ECS
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On-site presentation
Anwesha Maharana, Yarrik Vanwalleghem, Tinatin Baratashvili, and Stefaan Poedts

Coronal mass ejections (CMEs) interact with large-scale solar wind structures and other CMEs during their propagation in the heliosphere and undergo erosion, deflection, and deformation. In this work, we aim to quantify the erosion of the CMEs in different solar wind backgrounds using 3D MHD simulations. The EUropean Heliosphere FORecasting Information Asset (EUHFORIA; Pomoell and Poedts, 2018) is employed to create a relaxed solar wind background and evolve a CME on top of it between 0.1 au and 2 au. The LFF spheromak model is used to model the CME. Initially, we assume a simple dipolar background wind mimicking a solar minimum condition. CMEs with different geometric and magnetic field parameters (geometrical size, chirality, polarity, and magnetic flux) are evolved, and the evolution of the CME mass and the magnetic flux contained in the magnetic cloud is tracked to quantify mass and flux erosion. We also quantify the deformation of the CME during its evolution by parameterizing the separatrix surface of the magnetic cloud. The same experiment is repeated in the presence of a stream interaction region (SIR) interacting with the CME. We characterise the deformation of the different sides of the CME (with and without the interaction with SIR). In addition, we explore the adaptive mesh refinement and stretched grid features of the upgraded EUHFORIA heliospheric wind model, i.e., the newly developed ICARUS model (Verbeke et al., 2022) to resolve the CME shock and magnetic cloud and find the conditions to improve the modelling of the sheath region. Although the analysis of CME erosion has been carried out in 2.5D (axisymmetric) in previous works (Hosteaux et al., 2021), we explore the differences in 3D, which is required to fully quantify the erosion and deformation, and investigate their effect on the CME arrival time and geo-effectiveness at Earth.

How to cite: Maharana, A., Vanwalleghem, Y., Baratashvili, T., and Poedts, S.: Quantifying the effect of CME erosion on geo-effectiveness using EUHFORIA, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3444, https://doi.org/10.5194/egusphere-egu23-3444, 2023.

11:15–11:25
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EGU23-7972
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On-site presentation
Modeling  Heliospheric  Flux-Rope Distortions
(withdrawn)
Teresa Nieves-Chinchilla, Miguel A. Hidalgo, Hebe Cremades, and Andreas J. Weiss
11:25–11:35
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EGU23-2841
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ECS
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On-site presentation
Chaoran Gu, Verena Heidrich-Meisner, and Robert F. Wimmer-Schweingruber

Coronal Mass Ejections~(CMEs) are extremely dynamical large scale events in which plasma-not only the coronal plasma-is ejected into the interplanetary space. Their interplanetary counterparts measured in-situ are Interplanetary Coronal Mass Ejections (ICMEs), which is also an important part of space weather.

Even though the kinetic properties of the plasma might change because of dynamic effects occurring during the expansion of the CME, the heavy ion characteristics remain unchanged after it leaves the low corona. Charge states of heavy ions reflect important information about the coronal temperature profile due to the freeze-in effect, while elemental abundances indicate potential source regions of the plasma.

With the help of the Pulse Height Analysis (PHA) data from the Solar Wind Ion Composition Spectromet (SWICS) on board the Advanced Composition Explorer (ACE), combined with a newly developed multi-population model, we are able to conduct a high time resolution (12 minutes) case study on a complex ejecta detected by ACE in May 2005. This case lasted more than 80 hours and caused a strong geomagnetic response, with a Dst index at -247.

Multiple discontinuous periods with highly charged heavy ions are identified, elemental abundances also differ during those ”hot” periods. Heavy ion characteristics provide us an unique opportunity to see the boundaries of different parts of an ICME.

How to cite: Gu, C., Heidrich-Meisner, V., and Wimmer-Schweingruber, R. F.: Variations of high time resolution heavy ion characteristics in the complex May 2005 ICME, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2841, https://doi.org/10.5194/egusphere-egu23-2841, 2023.

11:35–11:45
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EGU23-16801
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ECS
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Virtual presentation
Souvik Roy and Dibyendu Nandy

Coronal Mass Ejections (CMEs) carry large amounts of magnetized plasma into the heliosphere at very high speeds. Their interplanetary counterparts, or Interplanetary CMEs (ICMEs), create adverse space weather conditions around planets. These interplanetary structures have the potential to cause hazardous space weather and impact space- and ground-based technologies on Earth. At CESSI we have developed a 3D magnetohydrodynamic STORM Interaction (CESSI-STORMI) module to simulate the interactions between ICMEs and planets with and without a global magnetosphere. In this talk, I shall discuss our data-driven simulations to assess ICME impact on the Earth’s magnetosphere and  present a methodology to estimate their geo-effectiveness. We validate this module with observations and find a good match with the observed values of the Dst index for past events. In addition, we also present a qualitative study of the global magnetosphere under the influence of ICMEs. Our work allows us to estimate the severity of geomagnetic storms based on early, data-driven inputs of ICME flux rope profiles gleaned from near-Sun or in-situ observations. Thus our work has the potential to significantly extend the time window for predicting the severity of geomagnetic storms - which remains a grand challenge in heliophysics.

How to cite: Roy, S. and Nandy, D.: A magnetohydrodynamic modelling approach to simulate CME-forced planetary magnetospheres and predict geomagnetic impacts, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16801, https://doi.org/10.5194/egusphere-egu23-16801, 2023.

11:45–11:55
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EGU23-8641
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ECS
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Virtual presentation
Nishtha Sachdeva, Gabor Toth, Ward Manchester, Bart van der Holst, Aniket Jivani, and Hongfan Chen

Successful modeling of Coronal Mass Ejections (CMEs) is an important step towards accurately forecasting their space weather impact. Therefore, it is crucial to improve the various models, techniques and tools to reconstruct CMEs while validating simulations with observations of the solar corona and the inner heliosphere at various heliospheric distances with multi-viewpoint observations.

The Space Weather Modeling Framework (SWMF) includes MHD modeling of the solar wind and CMEs from the Sun to the Earth and beyond. The Alfven Wave Solar atmosphere Model (AWSoM) is a 3D extended-MHD solar corona model within SWMF that reproduces the solar wind background into which CMEs can propagate. The Eruptive Event Generator (EEG) module within SWMF is used to obtain flux-rope parameters to model realistic CMEs within AWSoM using different flux-rope configurations.

In this work supported by the NSF SWQU and LRAC programs, we use an ensemble of solar wind backgrounds to obtain the best solar wind plasma environments into which CMEs can be launched. We vary the flux-rope parameters within a fixed range and obtain an ensemble of CME simulations to match the model reconstructed results with remote coronagraph observations near the Sun (LASCO C2/C3 and STEREO COR1/COR2) as well as with in-situ observations of solar wind plasma at 1 au. The ensemble modeling is a step forward towards improving the accuracy of the tools that provide flux-rope parameter estimates as well as the uncertainty quantification of CME modeling.

How to cite: Sachdeva, N., Toth, G., Manchester, W., van der Holst, B., Jivani, A., and Chen, H.: Ensemble modeling of CMEs to reconstruct remote and in-situ observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8641, https://doi.org/10.5194/egusphere-egu23-8641, 2023.

11:55–12:05
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EGU23-7390
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On-site presentation
Chin-Chun Wu, Kan Liou, Brian wood, and Lynn Hutting

Propagation of interplanetary (IP) shocks, particularly those driven by coronal mass ejections (CMEs), is still an outstanding question in heliophysics and space weather forecasting. Here we address effects of the ambient solar wind on the propagation of two CME-driven shocks from Sun to Earth. The two CME-driven shock events (CME03: April 3, 2010 and CME12: July 12, 2012) have the following properties: (1) driven by a halo CME (i.e., source location is near Sun-Earth line), (2) a southern hemispheric CME source location, (3) similar propagation speed (e.g., took ~2 days reach the Earth), (4) occurred in the non-quiet solar period, and (4) leading to a severe geomagnetic storm. What is interesting is that the initial (near the Sun) propagation speed, as measured by coronagraph images, of CME03 was slower (~300 km/s) than CME12, but it took about same time for both events to reach the Earth. According to in-situ solar wind observations from Wind, the CME03-driven shock was associated with a faster solar wind upstream of the shock than the CME12. This is also demonstrated in our global MHD simulations. This study emphasizes the importance of the background solar wind in the propagation of CME-driven shocks. Not only the initial propagation speed near the Sun but also the ambient solar wind speed is the key to timing the arrival of CME events. The present study also demonstrated that global MHD simulations with realistic solar wind inputs is able to precisely predict the arrival of CME events.

How to cite: Wu, C.-C., Liou, K., wood, B., and Hutting, L.: Effects of background solar wind on the propagation of coronal mass ejection driven shock, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7390, https://doi.org/10.5194/egusphere-egu23-7390, 2023.

12:05–12:15
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EGU23-9486
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ECS
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Virtual presentation
Evangelia Samara, Jasmina Magdalenic, Luciano Rodriguez, Stefaan Poedts, Manolis K. Georgoulis, Rui F. Pinto, Charles N. Arge, Stephan G. Heinemann, and Stefan J. Hofmeister

It is widely known that the fast solar wind originates mainly from coronal holes (CHs) in the solar corona. Associations between the CH characteristics and the properties of the fast solar wind in situ have been studied throughout the years from different authors leading to diverse degrees of correlation (Nolte et al. 1976; Vršnak et al. 2007; Karachik et al. 2011; Rotter et al. 2012a; Hofmeister et al. 2018; Heinemann et al. 2020). In this work, we introduce and quantify the geometrical complexity of CHs, a parameter that has been neglected so far in similar studies. For a particular CH sample, we explore how complexity affects the peak speed of the fast solar wind at Earth and its association with other CH properties. We further compare observations of fast solar wind at Earth with forecasts from EUHFORIA. We evaluate our results, and present the efforts and restrictions we encounter towards improving our prediction capabilities by exploiting recent PSP observations.

 

How to cite: Samara, E., Magdalenic, J., Rodriguez, L., Poedts, S., Georgoulis, M. K., Pinto, R. F., Arge, C. N., Heinemann, S. G., and Hofmeister, S. J.: The fast component of the solar wind: origins, correlations and modeling with EUHFORIA, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9486, https://doi.org/10.5194/egusphere-egu23-9486, 2023.

12:15–12:25
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EGU23-10248
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ECS
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Virtual presentation
Investigating the Evolution of Solar Wind Outflows by Using Radial and Non-Radial Tracking
(withdrawn)
Nathalia Alzate, Huw Morgan, Daniel Seaton, and Simone Di Matteo
12:25–12:30

Posters on site: Thu, 27 Apr, 14:00–15:45 | Hall X4

Chairpersons: Rui Pinto, David Barnes, Erika Palmerio
X4.211
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EGU23-5303
Marian Lazar, Rodrigo A. Lopez, Shaaban M. Shaaban, and Stefaan Poedts

Electrostatic wave instabilities induced by energetic electron beams are believed to be at the origin of radio emissions reported by the observations of interplanetary shocks and solar coronal sources. We revisit the electron beam-plasma configurations found susceptible to nonlinear radio (electromagnetic) emissions, but which led to contradictory outcomes both in the linear theory and especially in the numerical simulations. The results of a new dispersion and stability analysis are presented, in which the electron populations are modeled both with standard Maxwellian velocity distributions and with Kappa distributions revealed by in situ measurements. We thus describe not only the exact nature of these electrostatic fluctuations (e.g., electron beam modes, modified Langmuir waves, or electron acoustic waves), but also a series of characteristics that help to distinguish them in observations. The particle-in-cell simulations confirm the predictions of the linear theory, and show for the first time how the nonlinear radio emissions are modified due to the Kappa distributions of the electron populations.

How to cite: Lazar, M., Lopez, R. A., Shaaban, S. M., and Poedts, S.: The electrostatic electron beam-plasma instabilities and nonlinear radio emissions. Theory vs. PIC simulations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5303, https://doi.org/10.5194/egusphere-egu23-5303, 2023.

X4.212
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EGU23-12917
|
ECS
|
Irene Doria, Paolo Cappuccio, and Luciano Iess

The Mercury Orbiter Radio-science Experiment (MORE), onboard the ESA-JAXA mission BepiColombo, is dedicated to the study of Mercury’s interior structure and rotational state, and to fundamental physics tests. The MORE radiotracking system relies on a multi-frequency radio link: the onboard Deep Space Transponder receives an uplink in X-band and retransmits it back coherently in X- and Ka-band, the Ka-band transponder allows to establish a two-way link in Ka-band.

During the cruise phase, BepiColombo experienced four superior solar conjunctions. These periods, spanning for 15 days centered about the minimum impact parameter of the radio path between the spacecraft and the Earth, are exploited for tests of relativistic delay and Doppler shift. Thanks to the multi-frequency link the signal due to the solar corona plasma can be isolated through precise calibrations, exploiting the dispersive nature of the plasma1,2. This allows MORE to remove the plasma noise from the Doppler and range data in order to perform the fundamental physics test, but also to characterize the inner solar corona.

In this work we focus on the analysis of the data from the first (10th-24th March 2021) and second (29th January - 12th February 2022) solar conjunction experiments to characterize the properties of the solar wind.

For each radiotracking pass the power spectral density of Doppler measurements is compared with the expected power spectral index of a Kolmogorov turbulence (f-2/3)3.

Solar corona plasma data are also used to localize the plasma structures of the solar corona along the line of sight by means of cross-correlations between uplink and downlink time series of the plasma content obtained from Doppler data. This allows us to analyze in more detail large solar phenomena, such as coronal mass ejections.

Exploiting the collected open-loop recordings at high frequency (4 kHz), the solar wind velocity can be estimated assuming a theoretical model for the intensity spectrum4. The intensity timeseries are used to fit theoretical spectrum parameters (amplitude, velocity, axial ratio, inner scale of turbulence and power law index), characterizing the solar wind in the vicinity of the Sun.   

Finally, the range data set allows us to retrieve the total electron content along the radio path. This absolute measurement is used to adjust models of the solar wind density beyond four solar radii.

 

1 Bertotti et al, “Doppler tracking of spacecraft with multi-frequency links”,Astronomy and Astrophysics 269, 608-616, 1993

2 Bertotti et al, “A test of general relativity using radio links with the Cassini spacecraft”, Nature 425, 374-376, 2003

3 R. Woo and J.W. Armstrong, “Spacecraft Radio Scattering Observations of the Power Spectrum of Electron Density Fluctuations in the Solar Wind”, Journal of Geophysical Research 84, no. Al2, 1979

4 S. L. Scott, W. A. Coles and G. Bourgois, “Solar wind observations near the sun using interplanetary scintillation”, Astronomy and Astrophysics 123, 207-215, 1983

How to cite: Doria, I., Cappuccio, P., and Iess, L.: Probing the solar corona with Doppler and range measurements of the spacecraft BepiColombo, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12917, https://doi.org/10.5194/egusphere-egu23-12917, 2023.

X4.213
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EGU23-15636
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ECS
|
Giuseppina Carnevale, Mauro Regi, Patrizia Francia, and Stefania Lepidi

Alfvén waves play an important role in the stability, heating, and transport of magnetized plasmas. They are found to be ubiquitous in the solar wind, mainly propagating outward from the Sun, especially in high-speed streams emanating from coronal holes. When high-speed streams impinge on the Earth’s magnetosphere, the impact of Alfvénic fluctuations can cause magnetic reconnection between the intermittent southward IMF and the Geomagnetic field, leading to energy injection from solar wind into the Earth’s magnetosphere. In this work, we tested a rotation procedure from the
Heliocentric Earth Ecliptic (HEE) to the Mean-Field Aligned (MFA) reference frame, identified by means of the Empirical Mode Decomposition (EMD), of both solar wind velocity and interplanetary magnetic field at 1 AU. Our aim is to check the reliability of the method and its limitations in identifying Alfvénic fluctuations through the spectral analysis of time series in the MFA reference frame. With this procedure, we studied the fluctuations in the main-field-aligned direction and those in the orthogonal plane to the main field. To highlight the peculiarities of each case of study and be able to better identify Alfvén waves when applying this procedure to real data, we reproduced the magnetic and velocity fields of a typical corotating high-speed stream. We tested the procedure in several cases, by adding the presence of Alfvén waves and noise. We performed the spectral analysis of the MFA component of both magnetic and velocity fields to define the power related to the two main directions: the one aligned to the ambient magnetic field and the one orthogonal to it. The efficiency of the procedure and the result’s reliability are supported by Monte Carlo tests. The method is as well applied to a real case represented by a selected corotating solar wind stream. The results are also compared with those obtained by using the Elsässer variables to analyze the Alfvénicity of fluctuations via the cross-helicity, which is related to the degree of correlation between the solar wind velocity and the magnetic field fluctuations.

How to cite: Carnevale, G., Regi, M., Francia, P., and Lepidi, S.: On the validation of the rotation procedure from HEE to MFA reference frame in presence of Alfvén waves in the interplanetary medium, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15636, https://doi.org/10.5194/egusphere-egu23-15636, 2023.

X4.214
|
EGU23-14072
Assessment and Validation of Daily Enlil and EUHFORIA Simulations During 2019-2022
(withdrawn)
David Barnes
X4.215
|
EGU23-7135
|
ECS
Andreas Jeffrey Weiss, Teresa Nieves-Chinchilla, Martin Reiss, and Christian Moestl

We present the latest results in our ongoing work to construct a generalized analytical flux rope model. Our previously published writhed flux rope model is extended to include non-circular cross-sections to better mimic the magnetic field measurements that are seen in situ and imaging observations. We implement our new model within the scope of a fast forward simulation model that propagates a flux rope away from the Sun into the heliosphere and can generate synthetic magnetic field measurements at arbitrary positions. This flux rope is continuously deformed along its axis due to interaction with the ambient solar wind which is provided by other models. We use our model and the forward simulation in an attempt to reconstruct the global picture of a particular multi-point ICME event.

How to cite: Weiss, A. J., Nieves-Chinchilla, T., Reiss, M., and Moestl, C.: Modeling ICME flux ropes as bent and distorted tubes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7135, https://doi.org/10.5194/egusphere-egu23-7135, 2023.

X4.216
|
EGU23-87
On Relationship Between EIT Waves,  Solar Winds and CMEs  Phenomena
(withdrawn)
Virendra Verma
X4.217
|
EGU23-485
|
ECS
|
Devojyoti Kansabanik, Surajit Mondal, and Divya Oberoi

Measurements of the plasma parameters of coronal mass ejections (CMEs), particularly the magnetic field and non-thermal electron population entrained in the CME plasma, are crucial to understand their propagation, evolution, and geo-effectiveness. Spectral modeling of gyrosynchrotron (GS) emission from CME plasma has been regarded as  one of the most promising methods to estimate spatially resolved CME plasma parameters remotely. The very low flux density of CME GS emission, however, makes this rather  challenging. This challenge has recently been overcome using the high dynamic range imaging capability of the Murchison Widefield Array (MWA). Although the detection of GS is now possible routinely, the large number of free parameters of the GS models and some degeneracies between the values of these parameters make it hard to estimate all of them from the observed spectrum alone. These degeneracies can be broken using polarimetric imaging. In this work, we demonstrate this using our newly developed capability of robust polarimetric imaging on the data from the MWA. Very interestingly, we find that spectro-polarimetric imaging not only breaks the degeneracies but also provides tighter constraints on a larger number of plasma parameters than possible with total intensity spectroscopic imaging alone. 

How to cite: Kansabanik, D., Mondal, S., and Oberoi, D.: Deciphering Faint Gyrosynchrotron Emission from Coronal Mass Ejection using Spectro-polarimetric Radio Imaging, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-485, https://doi.org/10.5194/egusphere-egu23-485, 2023.

X4.218
|
EGU23-2405
Igor Sokolov, Tamas Gombosi, and Lulu Zhao

We provide exact analytical solutions for the magnetic field produced by prescribed current distributions located inside a toroidal filament of finite thickness. In application to the MHD equilibrium of a twisted toroidal current loop in the solar corona, the Grad-Shafranov equation is decomposed into an analytic solution describing an equilibrium configuration against the pinch-effect from its own current and an approximate solution for an external strapping field to balance the hoop force.  Our solutions can be employed in numerical simulations of coronal mass ejections. When superimposed on the background solar coronal magnetic field, the excess magnetic energy of the twisted current loop configuration can be made unstable by applying flux cancellation to reduce the strapping field. Such loss of stability accompanied by the formation of an expanding flux rope is typical for the Titov-Dèmoulin eruptive event generator. The main new features of the proposed model are:

i)   The filament is filled with finite β plasma with finite mass and energy,
ii)  The model describes an equilibrium solution that will spontaneously erupt due to magnetic reconnection of the strapping magnetic field arcade, and
iii) There are analytic expressions connecting the model parameters to the asymptotic velocity and total mass of the resulting CME, providing a way to connect the simulated CME properties to multipoint coronograph observations.

How to cite: Sokolov, I., Gombosi, T., and Zhao, L.: A Titov-Dèmoulin Type CME Generator for Finite β Plasmas, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2405, https://doi.org/10.5194/egusphere-egu23-2405, 2023.

X4.219
|
EGU23-9898
|
ECS
Eleanna Asvestari, Tobias Rindlisbacher, Jens Pomoell, Emilia Kilpua, and Ranadeep Sarkar

Interplanetary magnetic clouds with flux rope structures are an essential ingredient of space weather models. The main aim is to reconstruct their magnetic field topology and plasma properties and track their evolution in space and time. This has led to the implementation of a variety of flux rope configurations in magnetohydrodynamic models, with spheromak, modified spheromak, and more general toroidal flux ropes being commonly used.  

The spheromak implementation in EUHFORIA (EUropean Heliospheric FORecasting Information Asset) brought to light different manifestations in the simulation domain of a phenomenon called the spheromak tilting (instability). The latter is caused by a torque that is exerted on the spheromak when its magnetic moment forms an angle with the ambient field. The torque forces the spheromak to rotate until it reaches a state of reduced magnetic potential energy. This is a simplified description of the fact that the Lorentz force exerted by the ambient magnetic field on the toroidal currents in the spheromak has in general a rotational component, resulting in a net-torque. As not only spheromaks but also other types of flux ropes carry toroidal currents, these should experience a torque as well. To what extent it affects their evolution is a matter of a game of forces. Being thus able to track the evolution (the position, orientation, etc.) of flux ropes is crucial. 

We have developed a tool to perform such a tracking for the spheromak implementation in EUHFORIA. The tool uses magnetic field and plasma threshold criteria to locate the spheromak and estimate its magnetic moment. It was originally developed and applied to spheromaks inserted in synthetic uniform ambient plasma and unipolar ambient fields that are realistic only locally along the spheromak trajectories. Since its initial development, the tool has been further improved and made capable of dealing with more realistic ambient field scenarios, containing current sheets and high-speed streams. 

How to cite: Asvestari, E., Rindlisbacher, T., Pomoell, J., Kilpua, E., and Sarkar, R.: Tracking the evolution of spheromak flux ropes in ambient interplanetary magnetic field and plasma environments., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9898, https://doi.org/10.5194/egusphere-egu23-9898, 2023.

X4.220
|
EGU23-7413
|
ECS
Daniel Price, Jens Pomoell, and Emilia Kilpua

Twist is an intrinsic property of magnetic flux ropes that aids in understanding their evolution and eruption. It can be difficult to compute, resulting in the common use of approximations that do not consider the geometry of the flux ropes. However, while these approximations are often relatively simple to compute, their results require careful evaluation to ensure they are correctly understood. Consequently, the magnetic field analysis tools (MAFIAT) Python package has been developed to compute the geometrically-based twist of coronal flux ropes. Here we describe MAFIAT’s initial features, its Jupyter notebook-based operation, its scientific relevance, and our plans for its future development.

How to cite: Price, D., Pomoell, J., and Kilpua, E.: MAFIAT: Magnetic Field Analysis Tools, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7413, https://doi.org/10.5194/egusphere-egu23-7413, 2023.

X4.221
|
EGU23-6807
|
ECS
Chaitanya Sishtla, Jens Pomoell, Emilia Kilpua, Simon Good, and Rami Vainio

Alfvénic fluctuations of various scales are ubiquitous in the solar wind, with their non-linear interactions and eventual cascade resulting in an important heating mechanism to accelerate the solar wind via turbulent heating. Such fluctuations are also present in other transient & coherent plasma structures such as Coronal Mass Ejections (CMEs), and exhibit varying properties as compared to the solar wind plasma. In this study we investigate the interactions between solar wind Alfvénic fluctuations and CMEs using MHD simulations. We use an ideal magnetohydrodynamic (MHD) model with an adiabatic equation of state. An Alfvén pump wave is injected into the quiet solar wind by perturbing the transverse magnetic field and velocity components, and a CME is injected by inserting a flux-rope modelled as a magnetic cloud into the quasi-steady solar wind.

We observe that upstream Alfvén waves experience a decrease in frequency and change in the wave vector direction due to the non-spherical topology of the CME shock front. The CME sheath inhibits the transmission of low frequency fluctuations due to the presence of non-radial flows in this region. The frequency of the solar wind fluctuations also affect the steepening of MHD fast waves causing the CME shock propagation speed to vary with the solar wind fluctuation frequencies.

How to cite: Sishtla, C., Pomoell, J., Kilpua, E., Good, S., and Vainio, R.: Modelling the Interaction of Alfvénic fluctuations with Coronal Mass Ejections in the low solar corona, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6807, https://doi.org/10.5194/egusphere-egu23-6807, 2023.

X4.222
|
EGU23-17122
|
ECS
luis linan, Florian Regnault, Barbara Perri, Michaela Brchnelova, Blazej Kuzma, Andrea Lani, and Stefaan Poedts
Some space weather forecasting tools, such as the EUropean Heliosphere FORecasting Information Asset (EUHFORIA), consist of two parts. The first is a semi-empirical coronal model used to create the background solar wind, and the second is a heliospheric model in which coronal mass ejections (CMEs) are injected through the inner boundary located at 0.1 AU. In these models, the inserted CME does not interact with the solar wind before the inner boundary.
 
To take this interaction into account and provide a more realistic description of CMEs at 0.1 AU. We studied the propagation of flux ropes from the solar surface to 0.1 AU in a full magnetohydrodynamic coronal model called COCONUT (COolfluid COroNal UnsTructured). The CMEs were modeled using the modified Titov-Démoulin model (TDm) of flux rope. We tracked the evolution of twenty four different twisted flux ropes within realistic corona configurations reconstructed by COCONUT from the GONG magnetic maps of both minimum and maximum solar activity. All CMEs are identical except for their net initial current.
 
Our results reflect dynamic expected by the standard flare model, such as presence of post-flare loops and the pinching of the CME's legs. However, the shape of the CME varies greatly depending on whether the solar wind corresponds to a minimum or a maximum activity, highlighting the crucial role of the solar wind in determining the geometry of CMEs. Once the flux ropes reach 0.1 AU, their thermodynamic and magnetic properties are extracted. We found that, for the two solar wind configurations, the synthetic profiles obtained are consistent with those that satellites could measured. Moreover, simple relationships are emphasised between the net initial current of flux ropes and the shape of the different synthetic profiles. 
 
Finally, using this CME description, the boundary conditions imposed on EUHFORIA (or other heliospheric models) should be more accurate than those provided by an independent CME model and therefore lead to more realistic forecasts.​
 

How to cite: linan, L., Regnault, F., Perri, B., Brchnelova, M., Kuzma, B., Lani, A., and Poedts, S.: Modelling the propagation of flux ropes in the coronal model COCONUT, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17122, https://doi.org/10.5194/egusphere-egu23-17122, 2023.

Posters virtual: Thu, 27 Apr, 14:00–15:45 | vHall ST/PS

Chairpersons: Rui Pinto, David Barnes, Erika Palmerio
vSP.7
|
EGU23-8425
Heliospheric Science From Gateway With HERMES
(withdrawn)
William R. Paterson, Daniel J. Gershman, Shrikanth G. Kanekal, Roberto Livi, Mark B. Moldwin, Eftyhia Zesta, Brent Randol, and Marilia Samara
vSP.8
|
EGU23-13296
|
ECS
Ranadeep Sarkar, Jens Pomoell, Emilia Kilpua, and Eleanna Asvestari

One of the major challenges in space weather forecasting is to reliably predict the magnetic structure of interplanetary coronal mass ejections (ICMEs) in the near-Earth space. In the framework of global MHD modelling, several efforts have been made to model the CME magnetic field from Sun to Earth. However, it remains challenging to deduce a flux-rope solution that can reliably model the magnetic structure of a CME. Spheromaks are one of the models that are widely used to characterize the internal magnetic structure of a CME. However, recent studies show that spheromaks are prone to experience a large rotation when injected in the heliospheric domain which may affect the prediction efficacy of CME magnetic field at 1 AU. Moreover, the fully inserted spheromaks do not have any legs attached to the Sun. In addition, due to the inherent topology of the spheromak, the in-situ signature may exhibit a double flux-rope-like profile not reproduced by standard locally cylindrical flux rope models. Aiming to study the dynamics of CMEs exhibiting different magnetic topologies, we implement a new flux-rope model in “European heliospheric forecasting information asset” (EUHFORIA). Our flux-rope model includes an initially force free toroidal flux-rope that is embedded in the low-coronal magnetic field. The dynamics of the flux rope in the low and middle corona is solved by a non-uniform advection constrained by the observed kinematics of the event. This results in a global non-toroidal loop-like magnetic structure that locally manifests as a cylindrical structure. At heliospheric distances, the evolution is modeled as a MHD process using EUHFORIA. We track the evolution of the flux-rope up to 1 AU and assess the model results with the observed in situ profile of the associated CME.  This work is an important step forward in developing a realistic CME model that can be used for reliable space weather forecasting.

How to cite: Sarkar, R., Pomoell, J., Kilpua, E., and Asvestari, E.: Implementing a toroidal flux rope model in EUHFORIA and assessing its performance in predicting CME magnetic-field at 1 AU, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13296, https://doi.org/10.5194/egusphere-egu23-13296, 2023.