How to cite: Kilpua, E., Good, S., Vainio, R., Ala-Lahti, M., Dresing, N., Gieseler, J., Koikkalainen, V., Osmane, A., Ruohotie, J., Soljento, J., Trotta, D., Cohen, C., Horbury, T., and Bale, S.: Turbulent structure of CME-driven sheath regions and their role as energizing charged particles in interplanetary space, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8897, https://doi.org/10.5194/egusphere-egu24-8897, 2024.

Interplanetary shocks are efficient sources of accelerated particles and are often associated with high-energy proton/ion flux enhancements known as energetic storm particle (ESP) events. In situ spacecraft observations of particle fluxes near the shocks can be used to obtain energy spectra, providing very useful information for the investigation of the acceleration mechanisms. In this work we analysed the kinetic energy spectra of proton flux enhancements associated with ESP events observed by various spacecraft. ESP events associated with diverse shock conditions and geometries (e.g. quasi-perpendicular and quasi-parallel) were investigated. In addition, some of the events occurred during intervals in which Solar Energetic Particle (SEP) events were also ongoing, providing a background of pre-accelerated particles. The analysis of the shape of the observed spectra was used to identify which are the most plausible acceleration mechanisms at work. The turbulent magnetic field fluctuations upstream and downstream of the shocks were also studied to the aim of obtaining information about their possible role in particle acceleration.

This research has been carried out in the framework of the CAESAR (Comprehensive spAce wEather Studies for the ASPIS prototype Realization) project, supported by the Italian Space Agency and the National Institute of Astrophysics through the ASI-INAF n. 2020-35-HH.0 agreement for the development of the ASPIS (ASI Space weather InfraStructure) prototype of scientific data centre for Space Weather.

How to cite: Lepreti, F., Chiappetta, F., Laurenza, M., Benella, S., and Consolini, G.: Proton energy spectra of energetic storm particle events and magnetic field turbulent fluctuations nearby the associated interplanetary shocks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14142, https://doi.org/10.5194/egusphere-egu24-14142, 2024.

Interplanetary (IP) shocks are important sites of particle acceleration in the Heliosphere and can be observed in-situ utilizing spacecraft measurements. Such observations, crucial to address important aspects of energy conversion for a variety of astrophysical systems.

From this point of view, Solar Orbiter provides observations of interplanetary shocks at different locations in the inner heliosphere with unprecedented time and energy resolution in the suprathermal (usually above 50 keV) energy range. The general trends observed by Solar Orbiter and other spacecraft in the near-Earth environment for such shocks, highlighting their typical parameters, will be presented first. Then, the presence shock-induced wave activity in association with such shocks and their association with the presence of energetic particles will be discussed, summarizing some of the work performed in the framework of the the Solar EneRgetic ParticlE aNalysis plaTform for the INner hEliosphere (SERPENTINE) Project funded by EU H2020. Finally, particular emphasis will be devoted on the role of space/time irregularities at IP shocks and their effect on suprathermal particle production, focusing on some of the most interesting shocks observed by Solar Orbiter. 

How to cite: Trotta, D., Hietala, H., Horbury, T. S., Vainio, R., Dresing, N., Dimmock, A., Blanco-Cano, X., Kartavykh, Y., Wimmer-Schweingruber, R., Kilpua, E., Jebaraj, I., Gieseler, J., Espinosa Lara, F., and Gomez Herrero, R.: Interplanetary shocks and particle energisation in the inner heliosphere, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15030, https://doi.org/10.5194/egusphere-egu24-15030, 2024.

Acceleration of charged particles in solar flares, during reconnection of magnetic field lines in coronal loops, and by shock waves in the solar corona and interplanetary space are some of the substantial physical processes being studied by the Solar Orbiter mission. Cross-analysis of the light curves of the non-thermal parts of X-ray flares energy spectra registered by the Spectrometer Telescope for Imaging X-rays (STIX), and high-energy charged particle spectrograms recorded by the Energetic Particle Detector (EPD) suite assist us in furthering our understanding of these events.

The anomalies and events in interplanetary space such as shocks, CIRs, ICMEs, solar and interplanetary radio bursts, SEPs being investigated in situ regime are typically associated with solar X-ray flares and/or SDO/AIA measurements of the solar atmosphere in multiple wavelengths when sources are on the visible side of the solar disk. In cases where the powerful flare occurs on the Sun's backside, the massive CME can reach the volumes in the interplanetary space right at the opposite side of the CME’s seed and manifests in different forms of irregularities in the solar wind parameters and magnetic field components as well in enhanced energetic particle fluxes. Such types of occasions are of particular interest due to their near-global impact on the inner heliosphere.

In this study, we conduct a cross-analysis of the data derived from the Solar Wind Analyzer Proton-Alpha Sensor (SWA-PAS), Magnetometer (MAG), and EPD suite onboard the Solar Orbiter for the period of 13-14 March 2023, when a high-speed CME launched from near 180° from Earth accelerated an enormous quantity of high energy charged particles, from electrons to iron ions. At the time SolO was located 26°East of the Earth-Sun line at a distance of about 0.6 au. Even so, the CME quickly reached the spacecraft and manifested as a very sharp and strong shock at the front of which particles were accelerated additionally. In the analysis, we involve the data from the Suprathermal Ion Spectrograph (SIS), the SupraThermal Electrons and Protons (STEP), and the Electron Proton Telescope (EPT) of the EPD suite.

This work is supported by the “Long-term program of support of the Ukrainian research teams at the Polish Academy of Sciences carried out in collaboration with the U.S. National Academy of Sciences with the financial support of external partners”.

How to cite: Dudnik, O., Yakovlev, O., Mason, G., Ho, G., Kouloumvakos, A., Wimmer-Schweingruber, R., Rodriguez-Pacheco, J., Espinosa Lara, F., Gómez Herrero, R., Dudnik, B., and Képa, A.: Energetic particles observed by Solar Orbiter associated with a sharp shock wave passage from the solar backside event of March 13-14, 2023, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21919, https://doi.org/10.5194/egusphere-egu24-21919, 2024.

Predictions of the intensities of solar particle events are often fraught with uncertainties. Insufficient knowledge and understanding of the solar sources of the particles, and the conditions in the corona and in the inner heliosphere, as well as magnetic connectivity, have been limiting factors in making further progress.
This presentation covers a study done by one of the Work Packages of the SERPENTINE project, and is based on the analysis of lists prepared by two other work packages of the same project, and logically consists of two parts.
In the first part we performed a statistical analysis of a list of 45 multi-spacecraft events in solar cycle 25 observed by five spacecraft located in the inner Heliosphere (Solar Orbiter, Parker Solar Probe, Stereo A, Bepi Colombo), and one located at 1 AU close to the Earth (SOHO or Wind). The list, while prepared with a focus on the detection of protons above 25 MeV by two or more spacecraft, contains also information about electron observations around 100 keV and 1 MeV, respectively.  Aiming to investigate the processes which are responsible for spreading energetic particles in longitude and latitude, and to estimate the importance of perpendicular diffusion in the latitudinal direction, we considered, together with other parameters, not only the longitudinal distances to the source, but also the differences in the total angle. In this part of our study we used methods such as correlation analysis and principal component analysis, and applied them to the list as a whole, as well as to different types of events. For example, we found that in the case of narrow-spread events perpendicular diffusion is sufficient to explain the spreading of particles from the solar source into the heliosphere, while in the case of wide-spread events an additional acceleration source is needed. We also evaluated the role of the speeds and sizes of the associated coronal mass ejections, as well as features of EUV waves appearing in the events, and relate different types of microwave (radio) emission to different groups of events.
In the second part of this work we performed a statistical analysis of a list of 61 interplanetary shocks, observed by Solar Orbiter.  By using a superposed epoch analysis, we built a statistical picture of ion time profiles around the shock front in several energy ranges. We also investigated which shock parameters are more important for particle energization by propagating interplanetary shocks, particularly in the case of an overlap in these lists.

This study has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 101004159 (SERPENTINE).

How to cite: Kartavykh, Y., Heber, B., Wimmer-Schweingruber, R. F., Dresing, N., Trotta, D., Kollhoff, A., Droege, H., Klassen, A., Kilpua, E., Gieseler, J., Droege, W., Gomez-Herrero, R., Espinosa Lara, F., Rodriguez-Garcia, L., Rodríguez-Pacheco, J., and Vainio, R.: Statistical study of multi-spacecraft events and shocks observed in solar cycle 25, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6233, https://doi.org/10.5194/egusphere-egu24-6233, 2024.

Solar Energetic Particle Analysis Platform for the Inner Heliosphere (SERPENTINE) is a 42-months-long EU/H2020 project that started in January 2021 and focuses on the physics of Solar Energetic Particle (SEP) acceleration and transport. The project (see https://serpentine-h2020.eu) provides answers for three science questions:

(Q1) what are the primary reasons for widespread SEP events;

(Q2) what are the mechanisms responsible for acceleration ions from suprathermal to near-relativistic energies in coronal and interplanetary shocks; and

(Q3) what is the role of shocks in the acceleration of electrons in SEP events.

SERPENTINE makes use of the present capabilities provided by inner heliospheric missions such as Solar Orbiter, Parker Solar Probe and BepiColombo. In addition to the scientific objectives, the project develops and releases to the community a large number of analysis tools to facilitate the interpretation of observations. Also event catalogs and high-level datasets are produced and distributed.

We will give a summary of the results of the project. Some of the science highlights include the several identified causes of widespread events related to both sources and transport (Q1), the role of local and averaged properties of shocks in ion acceleration (Q2), and the observational evidence of shocks as the primary accelerators of MeV electrons in gradual SEP events (Q3).

How to cite: Vainio, R., Dresing, N., Gieseler, J., Palmroos, C., Kilpua, E., Price, D., Trotta, D., Horbury, T., Kartavykh, Y., Heber, B., Wimmer-Schweingruber, R., Plotnikov, I., Gómez-Herrero, R., and Rodriguez-Pacheco, J.: Solar Energetic Particle Analysis Platform for the Inner Heliosphere (SERPENTINE): Summary of Project Results, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6382, https://doi.org/10.5194/egusphere-egu24-6382, 2024.

Collisionless shock waves (CSWs) in plasma, prevalent in diverse astrophysical contexts, are key to understanding cosmic particle acceleration. These shock waves, observable in environments from heliospheric planetary bow shocks to supernova remnants (SNRs), efficiently convert kinetic energy to thermal energy and accelerate particles to sub-relativistic and relativistic energies. A particular focus is on electrons accelerated by these shocks, as they generate electromagnetic radiation, making astrophysical shocks like SNRs observable. Despite their significance, gaps remain in our understanding of the dynamic mechanisms behind these universal accelerators, underscoring the necessity for in-depth, direct in situ measurements. Heliospheric shocks offer a unique opportunity for such in situ studies, particularly those that are strong and fast, potentially mirroring SNR shocks. This study highlights the groundbreaking in situ observations of the fastest heliospheric shock wave yet, traveling at nearly 1% the speed of light, captured by the pioneering Parker Solar Probe. Positioned just 0.23 astronomical units from the Sun, the probe directly measured the acceleration of electrons and ions to high energies amidst intense electromagnetic activity. A landmark discovery was the acceleration of electrons to ultra-relativistic speeds, with energies reaching up to 6 Million electron volts (MeV). This observation not only provides unprecedented insights into the mechanisms of particle acceleration in CSWs but also bridges the gap in our understanding of similar processes in more distant astrophysical phenomena like SNRs. The findings from the Parker Solar Probe open new avenues for exploring and comprehending the intricate processes of cosmic particle acceleration.

How to cite: Krasnoselskikh, V., Jebaraj, I. C., Agapitov, O., Vuorinen, L., Choi, K.-E., Gedalin, M., Wijsen, N., Afanasiev, A., Kouloumvakos, A., Mitchell, J. G., Vainio, R., Hill, M., and Raouafi, N.:  In situ Observations of Ultra-Relativistic ElectronAcceleration in the Fastest Heliospheric Shock Wave by Parker Solar Probe, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16660, https://doi.org/10.5194/egusphere-egu24-16660, 2024.

Solar energetic particles (SEPs) are bound to the interplanetary magnetic field (IMF) by the Lorentz force. The expansion of the IMF close to the Sun focuses the particle pitch-angle distribution, and scattering counteracts this focusing. Solar Orbiter observed an unusual solar particle event on 9 April 2022 when it was at 0.43 astronomical units (au) from the Sun. The inferred IMF along which the SEPs traveled was about three times longer than the nominal length of the Parker spiral.

Nevertheless, the pitch-angle distribution of the particles of this event is highly anisotropic, and the electrons and ions appear to be streaming along the same IMF structures. The angular width of the streaming population is estimated to be approximately 30 degrees. The highly anisotropic ion beam was observed for more than 12 h. This may be due to the low level of fluctuations in the IMF, which in turn is very probably due to this event being inside an interplanetary coronal mass ejection. The slow and small rotation in the IMF suggests a flux-rope structure. Small flux dropouts are associated with very small changes in pitch angle, which may be explained by different flux tubes connecting to different locations in the flare region. The unusually long path length along which the electrons and ions have propagated virtually scatter-free together with the short-term flux dropouts offer excellent opportunities to study the transport of SEPs within interplanetary structures. The 9 April 2022 solar particle event offers an especially rich number of unique observations that can be used to limit SEP transport models.

How to cite: Wimmer-Schweingruber, R. F., Yang, L., Kollhoff, A., Gomez-Herrero, R., Rodriguez-Pacheco, J., Espinosa, F., Cernuda, I., Ho, G. C., Mason, G. M., Warmuth, A., Owen, C. J., Rodriguez, L., Shukhobodskaia, D., Berger, L., Kühl, P., Heber, B., Wang, L., Bucik, R., and Malandraki, O.: Unusually long path length for a nearly scatter-free solar particle event observed by Solar Orbiter at 0.43 au, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2823, https://doi.org/10.5194/egusphere-egu24-2823, 2024.

A major impact on human and robotic space exploration activities is the sudden and prompt occurrence of solar energetic ion events. In 2023 and 2024,  {STEREO} is approaching the Earth from a behind position, soon passing Earth inside its orbit and thereafter moving ahead of Earth.  {STEREO} thus offers several unique opportunities during this passage. In the period from June 1 to November 1, 2023, 5 {SEP} events have been measured that cause proton fluxes of above 25~MeV to rise above 0.1 /(cm$^2$\; s\; sr\; MeV). Taking into account systematic and statistical uncertainties of the particle measurements we find a good agreement between both spacecraft.

The SOHO/EPHIN and STEREO/SEPTproject is supported under Grant 50~OC~2102 by the German Bundesministerium für Wirtschaft through the Deutsches Zentrum für Luft- und Raumfahrt (DLR). This study has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 101004159 (SERPENTINE).

How to cite: Heber, B., Banys, D., Berdermann, J., Dröge, H., Hörlöck, M., Kollhoff, A., Kühl, P., Malandraki, O., Martens, J., Posner, A., and Sierks, H.: The alignment of  STEREO-A and Earth: A unique opportunity to investigate Solar Energetic Particle events., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2836, https://doi.org/10.5194/egusphere-egu24-2836, 2024.

Numerical tools for realistic modelling of energetic processes in the heliosphere, with the prospect of forecasting space weather, are in high demand. Of particular interest are solar energetic particles (SEPs), comprising high-energy charged particles linked to solar eruptive phenomena. During large SEP events, protons can be accelerated to energies ranging from tens of MeV up to a few GeV per nucleon, posing a dangerous threat to astronauts and spacecraft. While the precise acceleration mechanism behind SEP events is still an open challenge, observations indicate that the intensities of SEPs are highly influenced by the large-scale solar wind configuration. Transient structures such as coronal mass ejections (CMEs) or stream interaction regions (SIRs) perturb the interplanetary (IP) magnetic field, ultimately altering the transport of SEPs. In this context, we share recent results obtained with the energetic particle transport code PARADISE. By utilising realistic and complex solar wind configurations derived from magnetohydrodynamic (MHD) models such as EUHFORIA and the MPI-AMRVAC-based model Icarus, the code solves the focused transport equation in a stochastic manner to obtain spatio-temporal intensity distributions of SEPs in the inner heliosphere. Our studies focus on particle acceleration at IP shocks related to CMEs and SIRs.

How to cite: Husidic, E., Wijsen, N., Poedts, S., and Vainio, R.: Modelling energetic particle transport with the PARADISE code, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6854, https://doi.org/10.5194/egusphere-egu24-6854, 2024.

   Solar energetic particle (SEP) events are major outbursts of energetic charged particle radiation from the Sun. These events are related to solar flares and fast coronal mass ejections (CMEs). Flares are presumed to accelerate particles in magnetic reconnection processes, whereas fast (speeds > 1000 km s^–1) CMEs drive shock waves through the corona that are known to be able to accelerate particles. Electron acceleration has traditionally been ascribed to reconnection in flares whereas proton acceleration is believed to be efficient in CME-driven shocks. Recent observational evidence [1], however, suggests that shocks may be important in electron acceleration as well. Almost all major eruptions are related to both flares and CMEs so the association of the accelerated particles to these eruptive phenomena is often subject to debate. Using novel spacecraft observations of strong SEP events detected in solar cycle 25, we aim at identifying the parent acceleration region of the observed electron and proton events.

We have analyzed a set of 45 SEP events between Nov 2020 and May 2023 using data from multiple spacecraft including Solar Orbiter, near-Earth spacecraft (SOHO and Wind), STEREO-A and BepiColombo. We make use of peak intensities of >25-MeV protons and ~100 keV and ~1 MeV electrons and perform correlation studies of these peak intensities with each other as well as with the associated flare intensity. We separate the events into those that are well-connected (angular separation ≤ 35°) or poorly-connected (angular separation > 35°) to the flare by the interplanetary magnetic field.

We find significant correlations between electron and proton peak intensities. While events detected by poorly-connected observers show a single population of events, consistent with the idea that these particles are all accelerated by the spatially-extended CME-driven shock, events observed in well-connected regions show two populations: One population has higher proton peak intensities that correlate with electron peak intensities similarly to the poorly-connected events. These are most likely shock associated.  The other population has low proton intensities that are less well correlated with electron peak intensities. This population is suggested to show a dominant contribution of the flare.

References:
[1] Dresing, N. Kouloumvakos, A., Vainio, R., Rouillard, A., Astrophys. J. Lett., 925, L2

How to cite: Farwa, G., Dresing, N., Gieseler, J., Palmroos, C., Vuorinen, L., Jensen, S., Heber, B., Kühl, P., Richardson, I., Valkila, S., and Vainio, R.: Electron and proton peak intensities in solar energetic particle events, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7917, https://doi.org/10.5194/egusphere-egu24-7917, 2024.

Solar Energetic Particle (SEP) events can pose a significant radiation hazard for human and robotic space exploration activities. Therefore SEP forecasting systems are needed to support operations. The REleASE system (A. Posner, 2007) utilizes the fact that near relativistic electrons (1 MeV electrons have 94% of the speed of light) travel faster than ions (30 MeV protons have 25% of the speed of light) and are always present in hazardous SEP events. Their early arrival can be used to forecast the expected proton flux. Originally REleASE uses real time data from SOHO/EPHIN near Earth. Since the instrument is aging we recently adapted the method to STEREO-A/HET and used the period from June to November 2023 when STEREO-A passed the Earth to compare the REleASE forecasts from the different instruments.

This study has received funding from the National Aeronautics and Space Administration under grant agreement No. TXS0150642 (HESPERIA RELEASE).

How to cite: Dröge, H., Heber, B., Kollhoff, A., Kühl, P., Malandraki, O., and Posner, A.: Solar Energetic Proton forecasting with REleASE during STEREO-A’s flyby of Earth, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9560, https://doi.org/10.5194/egusphere-egu24-9560, 2024.

Solar energetic particles (SEPs) are highly energetic charged particles that have their origin of acceleration in strong space-weather driving phenomena that the Sun produces, e.g., solar flares and coronal mass ejections. These particles pose a radiation hazard to both technological equipment and living organisms in space, which is why the nature of these events is an important subject of study in the modern age where space technology is being applied more and more every day.

An SEP event is the result of a burst of SEPs arriving at an observer. Especially the onset time of an SEP event at varying energies is a key piece of information in relating the in-situ particle measurements to the remote-sensing observations of solar eruptions. Accurate knowledge of the onset time is an indispensable requirement for identifying the acceleration mechanisms and the source of the energetic particles. What traditional methods lack, however, is the assessment of the uncertainty related to the onset time.

Our method employs a unique combination of a statistical quality control scheme, Poisson-CUSUM, coupled with statistical bootstrapping. By choosing random samples from the background intensity preceding an SEP event and varying the integration time of the data, the method is able to produce a set of distributions of possible onset times. From this set of distributions we extract the most probable onset time and uncertainty intervals relating to this set of distributions. 

The uncertainty of onset times in a range of different energies is also in a direct connection to the uncertainty of a derived path length and inferred solar injection time of the particles, two extremely important pieces of information that velocity dispersion analysis yields, which is yet another motivator behind developing the method presented here

This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101004159 (SERPENTINE).

How to cite: Palmroos, C., Dresing, N., and Gieseler, J.: A New Method for Finding SEP Event Onset Times and Evaluating Their Uncertainty: Poisson-CUSUM-bootstrap Hybrid Method, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10365, https://doi.org/10.5194/egusphere-egu24-10365, 2024.

Solar energetic particles (SEPs) pose a significant radiation hazard to both technologies and human beings in space. SEPs undergo acceleration to higher energy levels through various eruptive phenomena, specifically, solar flares and coronal mass ejections (CMEs). Based on these sources, SEP events can be classified as impulsive and gradual events, respectively, although more recent findings showed that large SEP events contain both sources (solar flare reconnection and CME shock waves). Greater risk is attributed to CME shock-driven events due to their larger quantity of accelerated particles and longer duration. In such SEP events, solar particles are considered to be accelerated by the diffusive shock acceleration process in CME-driven coronal shocks. The role of inhomogeneous magnetic field-induced adiabatic focusing in the one dimensional diffusive shock acceleration (DSA) process is not effectively studied. Hence, in our numerical study, we aim to understand the effects of adiabatic focusing on coronal shock acceleration and to investigate whether a free escape boundary could yield similar results in the absence of focusing. This involves employing two models: one featuring a finite and homogeneous upstream region, eliminating focusing, and another one incorporating a weakening magnetic field, facilitating particle escape through the focusing effect. We present the results from a one-dimensional oblique shock model with a mean free path similar to  Bell’s theory (Bell, 1978) using Monte Carlo simulations. This research is funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 955620.

References 

Bell, A. R. 1978, MNRAS, 182, 147

How to cite: Annie John, L., Nyberg, S., Vuorinen, L., Vainio, R., Afanasiev, A., Poedts, S., and Wijsen, N.: Effects of adiabatic focusing in 1D coronal shock acceleration, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11246, https://doi.org/10.5194/egusphere-egu24-11246, 2024.

We present a new multi-spacecraft SEP event catalog for events observed in solar cycle 25. Observations from five different viewpoints are utilized, which are provided by Solar Orbiter, Parker Solar Probe, STEREO A, BepiColombo, and the near-Earth spacecraft Wind and SOHO. The catalog is an output of the SERPENTINE project, funded through the European Union’s Horizon 2020 framework programme. We provide key SEP parameters for > 25 MeV protons, > 1 MeV electrons, and ∼100 keV electrons. Furthermore, basic parameters of the associated flare and type-II radio burst are listed, as well as the coordinates of the observer and solar source locations.

An event is included in the catalog if at least two spacecraft detect a significant proton event with energies > 25 MeV. SEP onset times are determined using the Poisson-CUSUM method. SEP peak times and intensities refer to the global intensity maximum. If different viewing directions are available, we use the one with the earliest onset for the onset determination and the one with the highest peak intensity for the peak identification. We furthermore aim at using the highest possible time resolution. Therefore, time averaging of the SEP intensity data is only applied if necessary to determine clean event onsets and peaks. 

Associated flares were identified using observations from near Earth and Solar Orbiter. Associated type II bursts were determined from ground-based observations in the metric frequency range and from spacecraft observations in the decametric range.

The current version of the catalog contains 45 multi-spacecraft events observed in the period from Nov 2020 until May 2023, of which 13 were widespread events and four were classified as narrow-spread events. Using X-ray observations by GOES/XRS and Solar Orbiter/STIX we were able to identify the associated flare in all but four events. Using ground-based and spacecraft radio observations we found an associated type-II radio burst for 40 events. In total the catalog contains 141 single event observations out of which 18 (39) have been observed at radial distances below 0.6 AU (0.8 AU). 

We acknowledge funding by the European Union’s Horizon 2020 research and innovation program under grant agreement No. 101004159 (SERPENTINE).   

How to cite: Dresing, N. and the SERPENTINE SEP Catalog Team: The solar cycle 25 multi-spacecraft solar energetic particle event catalog of the SERPENTINE project, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6092, https://doi.org/10.5194/egusphere-egu24-6092, 2024.

The recently expanded fleet of heliospheric spacecraft presents unique opportunities for exploring solar eruptive phenomena such as coronal mass ejections (CMEs) and solar energetic particles (SEPs) from multiple vantage points. However, the task of integrating diverse observations collected by different instruments across various spacecraft poses a notable challenge. To maximize the utilization of this data within the broader scientific community, the EU Horizon 2020 project SERPENTINE aims to offer a versatile array of tools. These tools, provided as open-source Python Jupyter Notebooks, cater to scientists with limited programming expertise. Alongside comprehensive examples illustrating the utilization of the multi-spacecraft spatial setup and solar magnetic connection plotter Solar-MACH, an analysis platform for studying the energetic particle component of the in-situ observations of SEP events has been developed. This analysis platform comprises visualization tools (e.g., energetic particle time series or dynamic spectra) and analytical software capable of automatically determining SEP onsets or estimating particle path length and injection time via a time-shift analysis approach. Our poster will provide an overview of the available toolkit and instructions on its utilization, which can be seamlessly accessed on SERPENTINE’s dedicated JupyterHub server in the cloud.

This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101004159 (SERPENTINE).

How to cite: Gieseler, J., Palmroos, C., Dresing, N., Kouloumvakos, A., Morosan, D. E., Price, D. J., Trotta, D., Vuorinen, L., Yli-Laurila, A., Asvestari, E., Valkila, S., and Vainio, R.: Open-Source Analysis Platform for Solar Energetic Particles provided by SERPENTINE, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10356, https://doi.org/10.5194/egusphere-egu24-10356, 2024.

Since its start in 2021, the Solar EneRgetic ParticlE aNalysis plaTform for the INner hEliosphere (SERPENTINE) Project funded by EU H2020 program is using multi-spacecraft observations to investigate the origin of Solar Energetic Particles (SEPs) and providing new tools and datasets for the heliophysics community. SERPENTINE distributes new catalogues covering past and recent multipoint observations of SEP events, as well as their associated coronal mass ejections and interplanetary shocks. New SEP-related high-level data products from BepiColombo and Solar Orbiter missions, with added scientific value will be also provided in the near future. In this work, we summarize the structure, contents, and functionalities of the SERPENTINE Project Data Center (https://data.serpentine-h2020.eu/), a web-based interface providing open access to the various catalogues and high-level data products resulting from the project.

This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101004159 (SERPENTINE).

How to cite: Gómez-Herrero, R., Espinosa Lara, F., Rodríguez-Pacheco, J., Rodríguez-García, L., Cernuda, I., Roco, M., Vainio, R., Dresing, N., Kartavykh, Y., Kilpua, E. K. J., Trotta, D., Plotnikov, I., Price, D., Heber, B., Horbury, T. S., and Wimmer-Schweingruber, R. F. and the The SERPENTINE Team: The SERPENTINE Project Data Center, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12767, https://doi.org/10.5194/egusphere-egu24-12767, 2024.

High energy protons and Helium in the heliosphere originate from multiple sources. Solar Energetic Particle events (SEPs), Anomalous Cosmic Rays (ACRs) and Galactic Cosmic Rays (GCRs) are prominent examples. Their energy spectra provide insights into acceleration and transportation processes.

The SOlar and Heliospheric Observatory (SOHO) was launched December 1995 with the Electron Proton Helium INstrument (EPHIN) measuring protons and Helium from 4 MeV/nuc to 52 MeV/nuc with an additional open ended integral channel. However, its measuring capability was reduced due to the loss of two detectors in 1997 and 2017, respectively.

Using Pulse Height Analysis (PHA) data in the integral channel, we present methods to derive energy spectra for protons up to more than 100 MeV and Helium spectra up to some 250 MeV/nuc. First results and comparisons to other instruments will be presented.

The SOHO/EPHIN project is supported under Grant 50 OC 2102 by the German Bundesministerium für Wirtschaft through the Deutsches Zentrum für Luft- und Raumfahrt (DLR). This study has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 101004159 (SERPENTINE).

How to cite: Hörlöck, M., Jensen, S., Heber, B., Kühl, P., and Sierks, H.: High energy proton and Helium spectra from SOHOs Electron Proton Helium Instrument, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16054, https://doi.org/10.5194/egusphere-egu24-16054, 2024.

RADEM (Radiation Hard Electron Monitor) is a versatile detector of energetic particles designed for measurements of Jupiter's harsh radiation environment. It is one of the instruments on the ESA JUICE (Jupiter Icy Moons Explorer) mission launched on April 14^th, 2023. RADEM was switched on for a short commissioning phase shortly after the spacecraft launch and since August 2023 has been carrying on observations of the interplanetary radiation environment. The instrument will be operational throughout the JUICE mission from its cruise phase to the nominal scientific segment around the giant planet and its moons. RADEM was designed to detect electrons up to 40 MeV and protons up to 250 MeV enabling for covering of the most intense and hazardous regimes of the Jupiter radiation belts. Energy distributions of both protons and electrons are unfolded using eight semi-logarithmic energy bins. It allows for measurements of the spectral shapes and dynamic changes in the radiation intensity. RADEM also contains a detector sensitive to the direction of the incoming radiation with an angular coverage of 35% of the sky. Combined spectroscopic and angular measurements will allow for more accurate studies and mapping of the radiation around Jupiter and its moons. The instrument also has a dedicated heavy-ion detector designed to measure heavy-ion linear energy transfer between 0.1 and 10 MeV/cm/mg^-1. RADEM's primary purpose as a radiation monitor is to observe mission dose levels for safety concerns of the spacecraft and its scientific payload. In addition, its spectroscopic measurements in the higher energy range provide valuable extensions to other instruments from the JUICE payload. In particular, the Particle Environmental Package suite of instruments optimized for particle and ion energies up to about 1 MeV will obtain data prolongation up to about 100 MeV. RADEM operation during the cruise phase opens up a unique opportunity for conducting real-time, continuous observations of the Solar System radiation environment. It covers the current, twenty-fifth solar cycle including the solar maximum expected in 2025. With the JUICE-RADEM monitoring the radiation in the space between Venus and Mars orbits one obtains a data set useful for our future manned and unmanned explorations of these two neighboring planets. In this contribution, we will present the first RADEM observations of the interplanetary radiation environment including initial reports of detected SEPs (Solar Energetic Particles). The presented data set will cover the period since September 2023. The data will be correlated with observations from other instruments flying onboard spacecraft around the Earth or in interplanetary space such as e.g. BeppiColombo and Solar Orbiter.

How to cite: Hajdas, W. and Galli, A. and the RADEM collaboration: RADEM on JUICE's first observations of the interplanetary radiation environment , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15788, https://doi.org/10.5194/egusphere-egu24-15788, 2024.

A Ground Level Enhancement (GLE) event can be observed as an increase in the background of ground-based neutron monitor observations and is often associated with an increase of >500 MeV space-based proton flux measurements. GLE events begin as very high-energy SEP events associated with GeV protons. For such events to be detected at sea level, proton energies must exceed about 433 MeV. To mitigate for potential impacts on space systems, avionics and human health, space-based and ground-based monitoring of these particles is essential, and so is having reliable real-time warning systems. Here we present two products, respectively, “GLE alert++” and “HESPERIA UMASEP-500”, that have been fully integrated as federated products on the ESA SWE Portal for this purpose. GLE alert++, built by the Athens Cosmic Ray Group of the National and Kapodistrian University of Athens, issues alerts when a GLE event has been registered and is based on ground-based neutron monitor observations. From the space-based approach, the EU HORIZON2020 HESPERIA UMASEP-500 product provides forecasts of GLE events and >500 MeV protons relying on GOES satellite soft X-ray and high-energy proton observations. Examples of how these two products complement each other will be given, as well as how using them together can in some instances provide more information for users of these services. (Work performed in the frame of ESA Space Safety Programme’s network of space weather service development and pre-operational activities, and supported under ESA Contract 4000134036/21/D/MRP.)

How to cite: Crosby, N., Mavromichalaki, H., Malandraki, O., Gerontidou, M., Karavolos, M., Lingri, D., Makrantoni, P., Papailiou, M., Paschalis, P., and Tezari, A.: Very High Energy Solar Energetic Particle Events and Ground Level Enhancement Events: Forecasting and Alerts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17642, https://doi.org/10.5194/egusphere-egu24-17642, 2024.

It is shown that the first order Fermi acceleration of cosmic rays, based on a concept of ions reflected by shocks, is equivalent to the ballistic surfing acceleration (BSA) by the convection electric field. Despite big differences in the physics of the processes involved, both models lead to the same expression for the energy gain of a particle after one encounter with the shock, and consequently to the same power-law distribution of the cosmic ray energy spectrum after many encounters. BSA accelerates ions continuously from superthermal energies of 100eV up to very high energies observed in the cosmic ray spectrum. It is shown that the ‘knee’ observed in the spectrum at energy of 5×10¹⁵ eV could correspond to ions with gyroradius comparable to the size of shocks in supernova remnants.
It has been established that thermalization, heating, and energization of ions and electrons in collisionless shocks are related to the following plasma processes:

BSA – ballistic surfing acceleration
SWE –  stochastic wave energization
TTT – transit time thermalization
QAH – quasi adiabatic heating

References:
[1] K. Stasiewicz, MNRAS. 527, L71 (2023), Origin of flat-top electron distributions at the Earth’s bow shock, https://doi.org/10.1093/mnrasl/slad146
[2] K. Stasiewicz, MNRAS. 524, L50 (2023), Transit time  thermalization  and the stochastic wave energization of ions  in quasi-perpendicular shocks,  https://doi.org/10.1093/mnrasl/slad071
[3] K. Stasiewicz, B. Eliasson, MNRAS 520, 3238 (2023), Electron heating mechanisms at the bow shock - revisited with Magnetospheric Multiscale measurements, https://doi.org/10.1093/mnras/stad361

How to cite: Stasiewicz, K.: Reinterpretation of the Fermi acceleration of cosmic rays in terms of the ballistic surfing acceleration in shocks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4672, https://doi.org/10.5194/egusphere-egu24-4672, 2024.

How to cite: Romaneehsen, L., Marquardt, J., and Heber, B.: Charge sign dependence of recurrent Forbush Decreases in 2016, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18790, https://doi.org/10.5194/egusphere-egu24-18790, 2024.

Investigating the connection between solar variability and energetic radiation in the heliosphere is of fundamental importance for assessing radiation exposure and associated risks in space missions.

Our research focuses on the solar modulation phenomenon of cosmic rays, that is, on the long-term variation of the cosmic-ray flux and its association with the solar activity cycle.

Here we present our endeavors to establish an effective and predictive model of solar modulation. 
Our model incorporates fundamental physics processes of particle transport such as diffusion, drift, convection and adiabatic cooling, to compute the energy spectrum and temporal evolution of the cosmic radiation in the inner heliosphere.

Calibration and validation of our model are performed using the most recent cosmic-ray data from space-based detectors, such as AMS-02 on the International Space Station, along with multichannel observations of solar activity and interplanetary parameters.

This comprehensive model not only demonstrates good results in reproducing observations but also showcases its potential in space radiation monitoring and forecasting, offering valuable insights for evaluating exposure in future space missions.

How to cite: Pelosi, D., Bertucci, B., Tomassetti, N., Reis Orcinha, M., Fiandrini, E., and Barao, F.: An effective and predictive model for the long-term variations of Cosmic Rays in the Heliosphere", EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16994, https://doi.org/10.5194/egusphere-egu24-16994, 2024.

The activity of the Sun modulates the fluxes of galactic cosmic rays arriving at Earth. This heliospheric modulation of cosmic rays is often quantified by the modulation potential, which describes the average energy loss of particles during their transport in the heliosphere. The modulation potential is a useful parameter not only for understanding the behaviour of energetic particles in the heliosphere, but also as a measure of solar activity. However, the validity of the modulation potential, which utilizes the force-field methodology, is uncertain for shorter timescales, and often the estimates are only monthly or yearly.

Recently, an updated estimation of the modulation potential was done at a daily time resolution by utilizing neutron monitor (NM) measurements from 10 stations. We have now analysed the daily version and compared it (via a LIS model) to the variation of the daily GCR energy spectrum (for rigidities 1 to 100 GV) measured by the AMS-02 instrument in the ISS. We find that overall, the daily modulation potential works well for estimating daily count rates at different energies. The correspondence is lowest for the low energy bins, where we see an excess of particles, which seems to follow the solar cycle. For rigidities around 4-13 GV, we can see a very clear match, letting us estimate daily count rates for different energy bins with a few per cent accuracy. For higher energies, the noise background of the measurements masks the underlying variation.

The result is very interesting and promising for the feasibility of using the modulation potential estimates for shorter time scales. This will lead to a better understanding of the variability of the overall modulation and the possibility of utilizing and combining NM and spacecraft measurements. The results will be useful in space climate (e.g. long-term solar variation induced from cosmogenic isotopes) and space weather (e.g. CME's/Forbush decreases, CIR's, Flares/GLE's) research. Future work with additional datasets and analysis of the different LIS models is planned.

How to cite: Väisänen, P., Bertucci, B., Tomassetti, N., Orcinha, M., Duranti, M., and Usoskin, I.: Daily heliospheric modulation potential (V23) and modelled GCR dataset compared to space measurements of the GCR energy spectrum., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5753, https://doi.org/10.5194/egusphere-egu24-5753, 2024.

The Canadian SWeeping Energetic Particle Telescope (SWEPT) targets an assessment of the pitch angle dependence of particular space radiation, and will address and characterize the energy and directional dependence of this space radiation in the lunar environment. The project focuses on an assessment of the fundamental plasma processes which accelerate the particles to create this severe radiation hazard for astronauts in deep space, and assess radiation risk mitigation. By using an innovative sweeping look direction to determine the angular and energy dependence of the radiation on the Lunar Gateway, the SWEPT can assess the temporally evolving solar energetic particle (SEP) radiation in the heliosphere, emitted in solar eruptions and accelerated at interplanetary shocks, as well as address the impacts of primary and secondary radiation hazards on the Lunar Gateway. The SWEPT will also contribute to the development of effective deep space radiation mitigation strategies, such as those based on the early arrival of solar energetic electrons in advanceof SEP protons for humans on the lunar surface or in the lunar vicinity.

How to cite: Fedosejevs, R., Mann, I., Tiedje, H., Ozeke, L., Gan, K., Yu, B., Barona, D., Rowlands, N., Caldwell, D., Smith, K., and Amjad, M.: The Canadian SWeeping Energetic Particle Telescope (SWEPT): Steerable Energy and Pitch Angle Resolved Energetic Particle Measurements on the Lunar Gateway, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13125, https://doi.org/10.5194/egusphere-egu24-13125, 2024.

The fleet of present and future space missions aimed at studying the Sun and the solar-terrestrial relationships carry
particle detectors, among other instruments. The monitoring of intense solar activity and solar energetic particle (SEP)
events provide fundamental contributions to Space Weather and Space Weather science. Unfortunately, very few of these instruments are optimized
for the  measurement of the proton differential flux above 200 MeV/n. We show that by increasing this minimum energy to 400-600 MeV/n it is possible to infer the trend of the differential flux with small uncertainties up to GeV energies, while this is not the case if the measurements are limited  to 200 MeV/n. To this purpose, we report on the characteristics of a single instrument meant for the detection of  solar flares and high-energy particles, galactic magnetar activity and gamma-ray burst observations. The instrument is based on hydrogenated amorphous silicon as a sensitive material that presents an excellent radiation hardness and finds application for particle beam characterization and medical purposes.

How to cite: Grimani, C. and Sabbatini, F. and the HASPIDE Collaboration: A Hydrogenated amorphous silicon detector for Space Weather Applications, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10520, https://doi.org/10.5194/egusphere-egu24-10520, 2024.

    The exploration of the inner heliosphere has been limited by large gravitational potential differences. Consequently, the propagation processes of solar ejecta such as Interplanetary Coronal Mass Ejections (ICMEs) and Solar Energetic Particles (SEPs) are somewhat problematic. Recent orbital engineering developments and other advancements have enabled the deployment of multiple probes, such as BepiColombo and Solar Orbiter. This has provided a unique opportunity for multi-point observations of solar eruptions, allowing for the tracking of their radial and longitudinal evolution. 

    This study focuses on radiation data acquired by “Solar Particle Monitor (SPM)” onboard BepiColombo for solar physics. SPM is the housekeeping instrument, particularly more suited for highly energetic particles such as Solar Energetic Particles (SEP) and Galactic Cosmic Ray (GCR) than other instruments. However, it provides only time-series data of count rates and deposited energies. To extract valuable information about the incident charged particles, including their type, number, energy, and direction, a radiation simulation toolkit Geant4 (Allison et al., 2016) is employed.

    The mass SPM model was defined in the model space, incorporating an aluminum shield to estimate radiation shielding effects from surrounding equipment and walls of spacecraft. The thickness of the shield in each direction is determined by comparing SPM measurements with simulation results, identifying the combination of thicknesses that aligns most closely with observed trends. The study also reproduces the electron flux during BepiColombo's Earth swing-by in 2020 using the AE9 radiation model (Ginet et al., 2013), comparing the simulated results with actual measurements to determine effective shield thicknesses. Additionally, the method proposed by Park et al. (2021), utilizing transformation matrices to derive incident particle energy spectra from observed spectra, is applied.

    Our research extends the analysis to the recovery time constants of Forbush Decreases, resulting from ICME shielding GCR which the spacecraft encountered in 2022. The study aims to analyze the structural changes induced by the interaction between ICMEs and solar wind during their propagation. Future applications of the analysis are planned for Solar Energetic Particle (SEP) studies, contributing to the understanding of SEP propagation processes through multi-point observations.

    The implications of the results are significant, especially considering the predicted peak of the 11-year solar activity cycle in 2025. BepiColombo, having already captured numerous phenomena, necessitates further analysis using the established calibration method. The study underscores the potential applicability of housekeeping devices commonly equipped on spacecraft for scientific observations. If applied to other probes, similar methods not only expand the scope of scientific observations but also contribute to the growth of the solar observation network within the heliosphere.

How to cite: Kinoshita, G., Ueno, H., Murakami, G., and Yoshioka, K.: Simulation for the calibration of radiation data acquired by Solar Particle Monitor/MMO, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7297, https://doi.org/10.5194/egusphere-egu24-7297, 2024.