The low-energy ion event on 2020 June 19 measured by Solar Orbiter

Shortly after reaching the first perihelion, the Energetic Particle Detector (EPD) onboard Solar Orbiter measured a low-energy (<1 MeV/nuc) ion event whose duration varied with the energy of the particles. The increase above pre-event intensity levels was detected early on June 19 for ions in the energy range from ~50 keV to ~1 MeV and lasted up to ~12:00 UT on June 20. In the energy range from ~10 keV to < 40 keV, the ion event spanned from June 18 to 21. This latter low-energy ion intensity enhancement coincided with a two-step Forbush decrease (FD) as displayed in the EPD > 17 MeV/nuc ion measurements. On the other hand, no electron increases were detected. As seen from 1 au, there is no clear evidence of solar activity from the visible disk that could be associated with the origin of this ion event. We hypothesize about the origin of this event as due to either a possible solar eruption occurring behind the visible part of the Sun or to an interplanetary spatial structure. We use interplanetary magnetic field data from the Solar Orbiter Magnetometer (MAG), solar wind electron density derived from measurements of the Solar Orbiter Radio and Plasma Waves (RPW) instrument to specify the in-situ solar wind conditions where the ion event was observed. In addition, we use solar wind plasma measurements from the Solar Orbiter Solar Wind Analyser (SWA) suite gathered during the following solar rotation, for comparison purposes. In order to seek for possible associated solar sources, we use images from the Extreme Ultraviolet Imager (EUI) instrument onboard Solar Orbiter. Together with the lack of electron observations and Type III radio bursts, the simultaneous response of the ion intensity-time profiles at various energies indicates an interplanetary source for the particles. The two-step FD shape observed during this event suggests that the first step early on June 18 was due to a transient structure, whereas the second step on June 19, together with the ~50 &#8211;1000 keV/nuc ion enhancement, was due to a solar wind stream interaction region. The observation of a similar FD in the next solar rotation favours this interpretation, although a more complex structure cannot be discarded due to the lack of concurrent solar wind temperature and velocity observations.Different parts of this research have received funding from the European Union&#8217;s Horizon 2020 research and innovation programme under grant agreement No 870405 (EUHFORIA 2.0) and grant agreement No 01004159 (SERPENTINE).

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Using machine learning to identify magnetic reconnection in two-dimensional simulations

10.5194/egusphere-egu2020-12160 ◽

2020 ◽

Author(s):

Andong Hu ◽

Jannis Teunissen ◽

Manuela Sisti ◽

Francesco Califano ◽

Jérémy Dargent ◽

...

Keyword(s):

Machine Learning ◽

Solar Wind ◽

Magnetic Reconnection ◽

Solar Wind Plasma ◽

Space Physics ◽

Electron Velocity ◽

Two Dimensional ◽

The European Union ◽

Horizon 2020 ◽

Research And Innovation

<div>The understanding of fundamental processes at play in a collisionless plasmas such as the solar wind, is a frontier problem in space physics. We investigate here the occurrence of magnetic reconnection in a plasma with parameters corresponding to solar wind plasma and its interplay with a fully-developed turbulent state. Ongoing magnetic reconnection can, at the moment, be accurately identified only by humans. Therefore, as a first step, the goal of this study is to present a new method to automatically recognise reconnection events in the output of two-dimensional HVM (Hybrid Vlasov Maxwell)&#160;simulations&#160;where ions evolve by solving the Vlasov equation and the electrons are treated as a fluid with mass. A large dataset with labelled reconnection events was prepared, including parameters such as the magnetic field, the electron velocity field and the current density. We consider two types of machine learning models: classical approaches using on physics-based features, and convolutional neural networks (CNNs). We will investigate which approach performs better, and which input variables are most relevant. In addition, we will try to categorize magnetic reconnection regions (current sheets). This work has received funding from the European Union&#8217;s Horizon 2020 research and innovation programme under grant agreement No 776262 (AIDA, www.aida-space.eu).</div>

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Improving CME evolution and arrival predictions with AMR and grid stretching in EUHFORIA

10.5194/egusphere-egu21-9193 ◽

2021 ◽

Author(s):

Tinatin Baratashvili ◽

Christine Verbeke ◽

Nicolas Wijsen ◽

Emmanuel Chané ◽

Stefaan Poedts

Keyword(s):

Solar Wind ◽

Adaptive Mesh Refinement ◽

Adaptive Mesh ◽

Mhd Equations ◽

Efficiency Gain ◽

The European Union ◽

Interplanetary Shocks ◽

Horizon 2020 ◽

Research And Innovation ◽

Speed Up

Coronal Mass Ejections (CMEs) are the main drivers of interplanetary shocks and space weather disturbances. Strong CMEs directed towards Earth can cause severe damage to our planet. Predicting the arrival time and impact of such CMEs can enable to mitigate the damage on various technological systems on Earth.&#160;We model the inner heliospheric solar wind and the CME propagation and evolution within a new heliospheric model based on the MPI-AMRVAC code. It is crucial for such a numerical tool to be highly optimized and efficient, in order to produce timely forecasts. Our model solves the ideal MHD equations to obtain a steady state solar wind configuration in a reference frame corotating with the Sun. In addition, CMEs can be modelled by injecting a cone CME from the inner boundary (0.1 AU).Advanced techniques, such as grid stretching and Adaptive Mesh Refinement (AMR) are employed in the simulation. Such methods allow for high(er) spatial resolution in the numerical domain, but only where necessary or wanted. As a result, we can obtain a detailed, highly resolved image at the (propagating) shock areas, without refining the whole domain.These techniques guarantee more efficient simulations, resulting in optimised computer memory usage and a significant speed-up. The obtained speed-up, compared to the original approach with a high-resolution grid everywhere, varies between a factor of 45 - 100 depending on the domain configuration. Such efficiency gain is momentous for the mitigation of the possible damage and allows for multiple simulations with different input parameters configurations to account for the uncertainties in the measurements to determine them. The goal of the project is to reproduce the observed results, therefore, the observable variables, such as speed, density, etc., are compared to the same type of results produced by the existing (non-stretched, single grid) EUropean Heliospheric FORecasting Information Asset (EUHFORIA) model and observational data for a particular event on 12th of July, 2012. The shock features are analyzed and the results produced with the new heliospheric model are in agreement with the existing model and observations, but with a significantly better performance.&#160;&#160;This research has received funding from the European Union&#8217;s Horizon 2020 research and innovation programme under grant agreement No 870405 (EUHFORIA 2.0).

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Predicting geo-effectiveness of CMEs using a novel 3D CME model FRi3D integrated into EUHFORIA

10.5194/egusphere-egu21-11605 ◽

2021 ◽

Author(s):

Stefaan Poedts ◽

Anwesha Maharana ◽

Camilla Scolini ◽

Alexey Isavnin

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Field Strength ◽

Magnetic Field Strength ◽

Three Dimensional ◽

Flux Rope ◽

Future Perspective ◽

The European Union ◽

Horizon 2020 ◽

The Magnetic Field

Previous studies of Coronal Mass Ejections (CMEs) have shown the importance of understanding their geometrical structure and internal magnetic field configuration for improving forecasting at Earth. The precise prediction of the CME shock and the magnetic cloud arrival time, their magnetic field strength and the orientation upon impact at Earth is still challenging and relies on solar wind and CME evolution models and precise input parameters. In order to understand the propagation of CMEs in the interplanetary medium, we need to understand their interaction with the complex features in the magnetized background solar wind which deforms, deflects and erodes the CMEs and determines their geo-effectiveness. Hence, it is important to model the internal magnetic flux-rope structure in the CMEs as they interact with CIRs/SIRs, other CMEs and solar transients in the heliosphere. The spheromak model (Verbeke et al. 2019) in the heliospheric wind and CME evolution simulation EUHFORIA (Pomoell and Poedts, 2018), fits well with the data near the CME nose close to its axis but fails to predict the magnetic field in CME legs when these impact Earth (Scolini et al. 2019). Therefore, we implemented the FRi3D stretched flux-rope CME model (Isavnin, 2016) in EUHFORIA to model a more realistic CME geometry. Fri3D captures the three-dimensional magnetic field structure with parameters like skewing, pancaking and flattening that quantify deformations experienced by an interplanetary CME. We perform test runs of real CME events and validate the ability of FRi3D coupled with EUHFORIA in predicting the CME geo-effectiveness. We have modeled two real events with FRi3D. First, a CME event on 12 July 2012 which was a head-on encounter at Earth. Second, the flank CME encounter of 14 June 2012 which did not leave any magnetic field signature at Earth when modeled with Spheromak. We compare our results with the results from non-magnetized cone simulations and magnetized simulations employing the spheromak flux-rope model. We further discuss how constraining observational parameters using the stretched flux rope CME geometry in FRi3D affects the prediction of the magnetic field strength in our simulations, highlighting improvements and discussing future perspective.This research has received funding from the European Union&#8217;s Horizon 2020 research and innovation programme under grant agreement No 870405 (EUHFORIA 2.0)

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Modeling the Sun – Earth propagation of solar disturbances for the H2020 SafeSpace project

10.5194/egusphere-egu21-10796 ◽

2021 ◽

Author(s):

Benoit Lavraud ◽

Rui Pinto ◽

Rungployphan Kieokaew ◽

Evangelia Samara ◽

Stefaan Poedts ◽

...

Keyword(s):

Solar Wind ◽

Interplanetary Space ◽

Coronal Magnetic Field ◽

Physical Parameters ◽

The European Union ◽

Horizon 2020 ◽

Research And Innovation ◽

Reconstruction Methods ◽

Solar Disturbances ◽

Magnetic Field Computation

We present the solar wind forecast pipeline that is being implemented as part of the H2020 SafeSpace project. The Goal of this project is to use several tools in a modular fashion to address the physics of Sun &#8211; interplanetary space &#8211; Earth&#8217;s magnetosphere. This presentation focuses on the part of the pipeline that is dedicated to the forecasting &#8211; from solar measurements &#8211; of the solar wind properties at the Lagrangian L1 point. The modeling pipeline puts together different mature research models: determination of the background coronal magnetic field, computation of solar wind acceleration profiles (1 to 90 solar radii), propagation across the heliosphere (for regular solar wind, CIRs and CMEs), and comparison to spacecraft measurements. Different magnetogram sources (WSO, SOLIS, GONG, ADAPT) can be combined, as well as coronal field reconstruction methods (PFSS, NLFFF), wind (MULTI-VP) and heliospheric propagation models (CDPP 1D MHD, EUHFORIA). We aim at providing a web-based service that continuously supplies a full set of bulk physical parameters of the solar wind at 1 AU several days in advance, at a time cadence compatible with space weather applications. This work has received funding from the European Union&#8217;s Horizon 2020 research and innovation programme under grant agreement No 870437.

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Machine learning model of the plasmasphere to forecast satellite charging caused by solar storms.

10.5194/egusphere-egu21-15372 ◽

2021 ◽

Author(s):

Stefano Bianco ◽

Irina Zhelavskaya ◽

Yuri Shprits

Keyword(s):

Machine Learning ◽

Solar Wind ◽

Plasma Density ◽

Extreme Ultraviolet ◽

Geomagnetic Storms ◽

Learning Model ◽

Horizon 2020 ◽

Machine Learning Model ◽

Energetic Radiation ◽

Solar Storms

Solar storms are hazardous events consisting of a high emission of particles and radiation from the sun that can have adverse effect both in space and on Earth. In particular, the satellites can be damaged by energetic particles through surface and deep dielectric charging. The Prediction of Adverse effects of Geomagnetic storms and Energetic Radiation (PAGER) is an EU Horizon 2020 project, which aims to provide a forecast of satellite charging through a pipeline of algorithms connecting the solar activity with the satellite charging. The plasmasphere modeling is an essential component of this pipeline, as plasma density is a crucial parameter for evaluating surface charging. Moreover, plasma density in the plasmasphere has very significant scientific applications, as it controls the growth of waves and how waves interact with particles. Successful plasmasphere machine learning models have been already developed, using as input several geomagnetic indices. However, in the context of the PAGER project one is constrained to use solar wind features and Kp index, whose forecasts are provided by other components of the pipeline. Here, we develop a machine learning model of the plasma density using solar wind features and the Kp geomagnetic index. We validate and test the model by measuring its performance in particular during geomagnetic storms on independent datasets withheld from the training set and by comparing the model predictions with global images of He+ distribution in the Earth&#8217;s plasmasphere from the IMAGE Extreme UltraViolet (EUV) instrument. Finally, we present the results of both local and global plasma density reconstruction.&#160;

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Solar wind charge exchange in cometary atmospheres

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834881 ◽

2019 ◽

Vol 630 ◽

pp. A37 ◽

Cited By ~ 6

Author(s):

Cyril Simon Wedlund ◽

Etienne Behar ◽

Hans Nilsson ◽

Markku Alho ◽

Esa Kallio ◽

...

Keyword(s):

Solar Wind ◽

Charge Exchange ◽

Cross Sections ◽

Extreme Ultraviolet ◽

Solar Wind Plasma ◽

Analytical Models ◽

Sharp Drop ◽

Solar Wind Charge Exchange ◽

Comet 67P

Context. Solar wind charge-changing reactions are of paramount importance to the physico-chemistry of the atmosphere of a comet. The ESA/Rosetta mission to comet 67P/Churyumov-Gerasimenko (67P) provides a unique opportunity to study charge-changing processes in situ. Aims. To understand the role of these reactions in the evolution of the solar wind plasma and interpret the complex in situ measurements made by Rosetta, numerical or analytical models are necessary. Methods. We used an extended analytical formalism describing solar wind charge-changing processes at comets along solar wind streamlines. The model is driven by solar wind ion measurements from the Rosetta Plasma Consortium-Ion Composition Analyser (RPC-ICA) and neutral density observations from the Rosetta Spectrometer for Ion and Neutral Analysis-Comet Pressure Sensor (ROSINA-COPS), as well as by charge-changing cross sections of hydrogen and helium particles in a water gas. Results. A mission-wide overview of charge-changing efficiencies at comet 67P is presented. Electron capture cross sections dominate and favor the production of He and H energetic neutral atoms (ENAs), with fluxes expected to rival those of H+ and He2+ ions. Conclusions. Neutral outgassing rates are retrieved from local RPC-ICA flux measurements and match ROSINA estimates very well throughout the mission. From the model, we find that solar wind charge exchange is unable to fully explain the magnitude of the sharp drop in solar wind ion fluxes observed by Rosetta for heliocentric distances below 2.5 AU. This is likely because the model does not take the relative ion dynamics into account and to a lesser extent because it ignores the formation of bow-shock-like structures upstream of the nucleus. This work also shows that the ionization by solar extreme-ultraviolet radiation and energetic electrons dominates the source of cometary ions, although solar wind contributions may be significant during isolated events.

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Nature of Large-Scale Solar Magnetic Field and Complexity of HCS as Observed in Interplanetary Plasma

Symposium - International Astronomical Union ◽

10.1017/s0074180900088227 ◽

1990 ◽

Vol 142 ◽

pp. 343-344

Author(s):

T E Girish ◽

S R Prabhakaran Nayar

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Large Scale ◽

Solar Magnetic Field ◽

Solar Rotation ◽

Solar Wind Plasma ◽

Heliospheric Current Sheet ◽

The North ◽

Interplanetary Plasma ◽

South Asymmetry

The properties of the interplanetary plasma and magnetic field near 1 AU is determined by the nature of large-scale solar magnetic field and the associated structure of the heliospheric current sheet (HCS). Magnetic multipoles often present near the solar equator affect the solar wind plasma and magnetic field (IMF) near earth's orbit. The observation of four or more IMF sectors per solar rotation and the north-south asymmetry in the HCS are observational manifestations of the influence of solar magnetic multipoles, especially the quadrupole on the interplanetary medium (Schultz, 1973; Girish and Nayar, 1988). The solar wind plasma is known to be organised around the HCS. In this work, we have investigated the possibility of inferring i) the relative dipolar and quadrupolar heliomagnetic contributions to the HCS geometry from the observation of four sector IMF structure near earth and ii) the properties of the north-south asymmetry in HCS geometry about the heliographic equator from IMF and solar wind observations near 1 AU.

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Readout electronics of a prototype spectrometer for measuring low-energy ions in solar wind plasma

Nuclear Science and Techniques ◽

10.1007/s41365-016-0136-0 ◽

2016 ◽

Vol 27 (6) ◽

Cited By ~ 2

Author(s):

Di Yang ◽

Zhe Cao ◽

Xi Qin ◽

Xin-Jun Hao ◽

Shu-Bin Liu ◽

...

Keyword(s):

Solar Wind ◽

Solar Wind Plasma ◽

Low Energy ◽

Readout Electronics ◽

Low Energy Ions

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A self-consistent simulation of proton acceleration and transport near a high-speed solar wind stream

10.5194/egusphere-egu21-8189 ◽

2021 ◽

Author(s):

Nicolas Wijsen ◽

Evangelia Samara ◽

Àngels Aran ◽

David Lario ◽

Jens Pomoell ◽

...

Keyword(s):

Solar Wind ◽

Energetic Particle ◽

High Speed ◽

Three Dimensional ◽

Acceleration Process ◽

Solar Wind Stream ◽

The European Union ◽

Horizon 2020 ◽

Compression Waves ◽

Research And Innovation

Solar wind stream interaction regions (SIRs)&#160; are often characterised by energetic ion enhancements. The mechanisms accelerating these particles as well as the locations where the acceleration occurs, remains debated. Here, we report the findings of a simulation of a SIR-event observed by Parker Solar Probe at 0.56 au and the Solar Terrestrial Relations Observatory-Ahead at 0.96 au in September 2019 when both spacecraft were approximately radially aligned with the Sun. The simulation reproduces the solar wind configuration and the energetic particle enhancements observed by both spacecraft. Our results show that the energetic particles are produced at the compression waves associated with the SIR and that the suprathermal tail of the solar wind is a good candidate to provide the seed population for particle acceleration. The simulation confirms that the acceleration process does not require shock waves and can already commence within Earth's orbit, with an energy dependence on the precise location where particles are accelerated. The three-dimensional configuration&#160; of the solar wind streams strongly modulates the energetic particle distributions, illustrating the necessity of advanced models to understand&#160; these particle events.This research has received funding from the European Union&#8217;s Horizon 2020 research and innovation programme under grant agreement No 870405 (EUHFORIA 2.0).&#160;

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The Dynamic Time Warping as a means to assess modeled solar wind time series

10.5194/egusphere-egu21-12459 ◽

2021 ◽

Author(s):

Evangelia Samara ◽

Emmanuel Chane ◽

Brecht Laperre ◽

Christine Verbeke ◽

Manuela Temmer ◽

...

Keyword(s):

Time Series ◽

Solar Wind ◽

Dynamic Time Warping ◽

Optimal Alignment ◽

The European Union ◽

Time Warping ◽

Horizon 2020 ◽

Research And Innovation ◽

Single Number ◽

Dynamic Time

In this work, the Dynamic Time Warping (DTW) technique is presented as an alternative method to assess the performance of modeled solar wind time series at Earth (or at any other point in the heliosphere). This method can quantify how similar two time series are by providing a temporal alignment between them, in an optimal way and under certain restrictions. It eventually estimates the optimal alignment between an observed and a modeled series, which we call the warping path, by providing a single number, the so-called DTW cost. A description on the reasons why DTW should be applied as a metric for the assessment of solar wind time series, is presented. Furthermore, examples on how exactly the technique is applied to our modeled solar wind datasets with EUHFORIA, are shown and discussed.This project has received funding from the European Union&#8217;s Horizon 2020 research and innovation programme under grant agreement No 870437 (SafeSpace).

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