The ESA/NASA Solar Orbiter mission performed its first close solar encounters at 0.32 au in March 2022 and at 0.29 au in October 2022. By combining high-resolution imaging and spectroscopy of the Sun with detailed in-situ measurements of the surrounding heliosphere, Solar Orbiter enables us to study the Sun's corona in unprecedented detail, and determine the linkage between observed solar wind streams and their source regions on the Sun. Its science return will be enhanced significantly by coordinated observations with other space missions, e.g. Parker Solar Probe, as well as new ground-based telescopes like DKIST. Over the course of the 10-year mission, Solar Orbiter's highly elliptical orbit will get progressively more inclined to the ecliptic plane. Thanks to this new perspective, Solar Orbiter will deliver images and comprehensive data of the unexplored Sun’s polar regions and the Sun's far side. This talk will provide a status update of the mission and the science operations performed during the first two science perihelia, and summarise early science results.

How to cite: Zouganelis, Y., Müller, D., De Groof, A., Williams, D., Walsh, A., Janvier, M., Nieves-Chinchilla, T., Lario, D., and Musset, S.: Solar Orbiter: The Sun up close, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8923, https://doi.org/10.5194/egusphere-egu23-8923, 2023.

Upflows in the corona are of importance as they may contribute to the solar wind. Because of this, there has been interest
in the analysis of upflows at the edges of active regions (ARs). The coronal upflows that are seen at the edges of ARs have coronal
elemental composition and can contribute to the slow solar wind. The sources of the upflows have been challenging to determine
because they may be multiple.

In this talk, we will discuss the latest results of coronal upflows. This includes an example which is found unusually close to a sunspot umbra and unusually has photospheric abundance. We analyse in detail the cause of this upflow region using a combination of Solar Orbiter EUV images at high spatial and temporal resolution,
Hinode/EUV Imaging Spectrometer data, and observations from instruments on board the Solar Dynamics Observatory. This com-
bined dataset was acquired during the first Solar Orbiter perihelion of the science phase, which provided a spatial resolution of 356
km for 2 pixels.  In the location of the, a small positive polarity connects to the umbra
via small-scale and very dynamic coronal loops.  The Solar Orbiter EUV Imagers (EUI) high resolution data show the dynamics of these small loops, which last on timescales of only minutes. This is the location of the coronal upflow which has photospheric abundance. We attempt to determine if it is possible that they can feed into the slow solar wind. We discuss future observation potential using Solar Orbiter data along with data from other missions and ground-based observatories. This provides opportunities for multiple viewpoints, multi-wavelength measurements of these upflow regions.

How to cite: Harra, L., Mandrini, C., and Brooks, D. and the Solar Orbiter EUI collaborators: The source of unusual coronal upflows with photospheric abundance in a solar active region, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3094, https://doi.org/10.5194/egusphere-egu23-3094, 2023.

Observations of plasma motions in the low corona are often limited to magnetic field lines originating in active regions, which are ideal for spatial domain enhancements across individual extreme ultraviolet (EUV) images to see loops, flares, and other bright activity contrasted against dim background features.

The quiet Sun is essentially all dim background features, which requires advanced image processing and ideal observation parameters to emphasize the temporal domain in order to visualize faint, fine-scale plasma flows. We utilize time-normalized optical flow (TNOF) on large sets of high cadence EUV data by reducing instrumental noise to a high degree and then emphasizing the minor brightness variations indicative of plasma motion. Maps of plasma flow paths are produced via optical flow tracking algorithms by the computer vision method of Lucas-Kanade and the underlying velocity field is estimated with line integral convolution.

To test the effectiveness of the TNOF approach, we have applied this method to an EUV case study of data from EUI 174 and AIA 171 on 29 March 2022. This date marked a near-perpendicular line of sight orientation between the two spacecraft, had similarly short observation intervals, and provided the opportunity to compare contrast enhanced plasma features off-limb with temporally enhanced on-disk plasma motion. 

In this case study, we generated movies and flow paths that show TNOF succeeds at qualitatively outlining plasma flow along magnetic field lines from both Solar Orbiter’s and SDO’s point of view which are in general agreement with potential field models. Additionally, detailed velocities of plasma motion within coronal loops, overall velocity trends, and a new quasi-magnetic flow trend within the quiet Sun are presented.

How to cite: Muro, G. and Morgan, H.: Time-normalized plasma flow mapping during the quadrature of SolO and SDO, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15710, https://doi.org/10.5194/egusphere-egu23-15710, 2023.

Mini-filament eruptions are one of the most common small-scale transients in the solar atmosphere. However, their eruption mechanisms are still not understood thoroughly. Here, with a combination of 174 Åimages of high spatio-temporal resolution taken by the Extreme Ultraviolet Imager on board Solar Orbiter and images of the Atmospheric Imaging Assembly on board Solar Dynamics Observatory, we present a detailed investigation of an erupting mini-filament over a weak magnetic field region on 2022 March 4. It is clearly observed that, as the mini-filament quickly ascends, two ribbons appear underneath it. Subsequently, when the erupting mini-filament interacts with the outer ambient loops, some dark materials blow out, forming a blowout jet characterized by a widening spire. At the same time, multiple small bright blobs of size 1–2 Mm appear at the interaction region and propagate along the post-eruption loops towards the footpoints of the erupting fluxes at a speed of  100 km s􀀀1, as well as giving rise to a semi-circular brightening. These features indicate that the mini-filament eruption first undergoes the internal and then external reconnection, the latter of which mainly transfers mass and magnetic flux of the erupting mini-filament to the ambient corona.

How to cite: Li, Z., Cheng, X., Ding, M., Chitta, P., Peter, H., and Berghmans, D.: Evidence for External Reconnection Between an EruptingMini-filament and Ambient Loops Observed by Solar Orbiter/EUI, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9221, https://doi.org/10.5194/egusphere-egu23-9221, 2023.

In this work the analysis of the SOL2022-03-30 X1.4 GOES class flare is presented. This flare was observed by Solar Orbiter during perihelion as well as from Earth based observatories including SDO’s AIA and the Extended Owens Valley Solar Array (EOVSA). It displays well correlated fast time variation in the HXR and microwave wavelengths of emission with time dependent lags. The mechanism behind such observed puslations is not yet fully understood and is important for gaining an understanding of particle acceleration and energy release in solar flares. In this flare, the oscillatory behaviour grows in time and can be split into three phases with QPP periods ~7s, ~14s and ~35s. New capabilities from Solar Orbiter’s Spectrometer Telescope for Imaging X-rays (STIX) allows for the localisation of individual bursts on short timescales which enables us to determine the spatial morphology of the HXR emission and its evolution in time. The HXR source locations are compared with the microwave sources observed by EOVSA and the ribbon structure determined from AIA 1600Å and 1700Å. The QPP source locations are found to change significantly in time. Furthermore, the electron spectral index is anti-correlated with the observed HXR emission, obeying the soft-hard-soft relation. When combined, these observations point towards a mechanism for QPP generation which involves quasi-periodic energy release and injection of electrons into the flaring loop. However, several open questions remain about how these QPPs are generated.  

How to cite: Collier, H., Hayes, L., Battaglia, A., Harra, L., and Krucker, S.: SOL2022-03-30 X1.4 GOES Class Flare: Localising the source of quasi periodic pulsations in the Hard X-ray and microwave emissions with STIX onboard Solar Orbiter and EOVSA., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11801, https://doi.org/10.5194/egusphere-egu23-11801, 2023.

During nearly three years of operation, STIX aboard Solar Orbiter observed thousands of flares.   Many of them were simultaneously observed by Solar X-Ray Monitor (XSM) on board Indian Chandrayaan-2 circling the Moon.  We present results of a multi-wavelength study for  one selected flare  of M GOES class as seen from 1.a.u. STIX data provided  the opportunity for a detailed analysis of hard X-ray emission in several energy bands including the light curves, reconstructed hard X-ray images and spectra. The differential emission measure diagnostics of the flaring plasma have been carried out based on interpretation of the XSM X-ray spectra. Using the differential evolution (DE) approach we have determined the “full” model of emitting source including the temperature, emission measure and elemental abundances as determined simultaneously throughout the flare.  We discuss patterns of elemental composition history for individual plasma temperature components.

How to cite: Kepa, A., Siarkowski, M., Awasthi, A. K., Sylwester, B., and Sylwester, J.: A multi-thermal analysis of M-class flare observed  in common by STIX and XSM, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13784, https://doi.org/10.5194/egusphere-egu23-13784, 2023.

How to cite: Awasthi, A. K., Mrozek, T., Litwicka, M., Steslicki, M., Kolomanski, S., and Kulaga, K.: Thermal-nonthermal energy partition in weak flares observed by STIX, XSM, and SDO, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4805, https://doi.org/10.5194/egusphere-egu23-4805, 2023.

In this paper we will present preliminary results of an X-ray flare that occurred on 9^th May 2021 for which the thermal and non-thermal X-ray signatures were detected both from the Earth direction by Fermi/GBM  and by STIX on Solar Orbiter at 97° from the Sun-Earth line.  This flare was also well observed in radio with the ground-based instruments  in Nançay and in the interplanetary space by WIND/WAVES and RPW on Solar Orbiter . The X-ray event shows both an impulsive phase observed above 25 keV by STIX and FERMI and followed by a more gradual phase observed up to 15 keV by both STIX and FERMI. In the decimetric/metric radio domain, this event shows a group of type III bursts extending to the interplanetary medium as well as type IV emission.  We shall discuss here the relative temporal evolutions of HXR emissions at different energies with those of the radio fluxes at different frequencies, as well as the spatial evolution of the X-ray and radio sources during the different phases of the event. We shall also investigate the evolution of the characteristics of the non-thermal electrons detected in the corona associated to both implusive and gradual phase of the flare.

How to cite: Vilmer, N., Musset, S., Zhang, M., Klein, K.-L., and Paipa, D.: Energetic electrons in the solar corona  for the long duration event of 9 May 2021 as diagnosed from X-ray and radio observations., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11354, https://doi.org/10.5194/egusphere-egu23-11354, 2023.

Impulsive electron events observed in interplanetary space are believed to be generated by acceleration in solar flares. This notion has been supported by correlations between the characteristics of energetic electrons detected in-situ near 1 au and those in solar flares derived from hard X-ray observations. However, the details of this relation are still unclear, presumably because of the complex combination of acceleration, injection, and transport effects that are involved.

We present the first statistical results on impulsive electron events obtained by joint observations of remote-sensing and in-situ instruments on Solar Orbiter. We use the suite Energetic Particle Detector (EPD) to measure the properties of the electrons (time profile, anisotropy, maximum energy, inferring the injection time at the source, etc.), as well as to determine the particularities of the composition in the suprathermal energy range. Also, X-ray observations from the Spectrometer/Telescope for Imaging X-rays (STIX) constrain the energetic electrons in the solar flare in terms of timing, spectrum, and location. Type III radio bursts detected by the Radio and Plasma Waves (RPW) instrument are used to link the nonthermal X-ray peaks to the interplanetary electron beams. Finally, the Extreme Ultraviolet Imager (EUI) provides context on the flare evolution. We use a large event sample obtained during the first 2.5 years of the Solar Orbiter mission, which covers a wide range of radial distances ranging from as close as 0.33 au to 1.02 au.

How to cite: Warmuth, A., Schuller, F., Gómez-Herrero, R., Rodríguez-Pacheco, J., Carcaboso, F., Krucker, S., Pacheco, D., Wimmer-Schweingruber, R., Kollhoff, A., Dresing, N., Fedeli, A., Paipa, D., Maksimovic, M., Vilmer, N., Barczynski, K., Podladchikova, O., Mason, G., and Rouillard, A. and the Joint STIX-EPD-RPW-EUI Working Group: First results on interplanetary electron events obtained by joint observations of remote-sensing and in-situ instruments on Solar Orbiter, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7482, https://doi.org/10.5194/egusphere-egu23-7482, 2023.

It is well known that flare-accelerated electrons can produce both hard X-ray (HXR) emission and Type-III radio bursts. The HXR emission is produced by the accelerated electrons propagating towards the chromosphere where they deposit their energy while Type-III radio bursts are produced by the accelerated electron beams traveling towards the outer solar atmosphere. Hence a temporal correlation between these two kinds of emission may imply a common origin of the accelerated electrons providing insight into the acceleration process, and allows us to connect electrons at the Sun to those in the heliosphere. On 2022-Nov-11 11:30 - 12:00 UT, the Spectrometer Telescope for Imaging X-rays (STIX) on Solar Orbiter observed a highly energetic flare event with an excellent time resolution of 0.5 s. Simultaneously there were observations of multiple coronal and interplanetary Type-III radio bursts from several instruments such as I-LOFAR, WIND/WAVES, NDA and ORFEES. I-LOFAR provides high-sensitivity imaging spectroscopy in the range of ~10-240 MHz with a time resolution of 1.31 ms and a frequency resolution of 195 kHz. We examine the temporal correlation between the X-ray and radio time series and discuss the relationship between the two and what it implies   about the origin of the electron populations producing these two kinds of radiation.

How to cite: Bhunia, S., Hayes, L., Maloney, S., and Gallagher, P.: Detailed look at the temporal correlation between hard X-ray flare and type III radio bursts, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16350, https://doi.org/10.5194/egusphere-egu23-16350, 2023.

Magnetic reconnection is a fundamental process in astrophysical plasma, as it enables the dissipation of energy at kinetic scales. Detecting it in-situ is therefore key to further our understanding of energy conversion in space plasma. However, ion reconnection jets usually scale from seconds to minutes in-situ, and as such they can be quite tedious to find in the months or years of data provided by Wind, ACE, Helios, PSP and Solar Orbiter.

In this work, we use a new approach to identify automatically reconnection exhausts in-situ. The method strongly relies on the Walén relation and uses Bayesian inference as well as physical considerations to detect reconnection jets in-situ. Applying the detection algorithm to one month of Solar Orbiter data at 0.7 ~AU, we find an occurrence rate of 6.4~jets/day, which is significantly higher than in previous studies performed at 1~AU.  We repeat the analysis over the Solar Orbiter perihelion at 0.3 AU and show that the occurrence rate of magnetic reconnection tends to increase with radial distance.

We show that magnetic reconnection exhausts clearly cluster in the solar wind. We perform a statistical analysis, distinguishing between the exhausts associated with the heliospheric current sheet and turbulent reconnection. We find that the source and the degree of Alfvénicity of the solar wind might have an impact on magnetic reconnection occurrence.

How to cite: Fargette, N., Lavraud, B., Rouillard, A., Houdayer, P., Phan, T., Oieroset, M., Eastwood, J., Fedorov, A., Louarn, P., Owen, C., and Horbury, T.: Solar Orbiter reveals that reconnection jets cluster in the solar wind, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16072, https://doi.org/10.5194/egusphere-egu23-16072, 2023.

Parker Solar Probe has detected abundant magnetic inversions and velocity spikes in the young solar wind, the origins of which are still highly debated. Numerous studies based on observational data and numerical simulations favor the causal correlation between interchange magnetic reconnection process and these velocity spikes. However, the specific process by which interchange magnetic reconnection leads to these structures is still inconclusive. Interchange reconnection should occur during the eruption of small bipoles in pre-existing open magnetic field regions such as coronal holes. This process is known to drive the formation of plumes and pseudo-streamer like structures and potentially mesoscale structures measured in the solar wind as well as velocity spikes. Using velocity measurements from Solar Orbiter we infer the magnetic origin of mesoscale structures and velocity spikes measured by Solar Orbiter, we find that the footpoints of the magnetic lines associated with these spikes are located at the boundary of a coronal hole observed by the Solar Dynamics Observatory (SDO), where the interchange magnetic reconnection is likely to occur. The imaging instruments aboard Solar Orbiter and SDO record one typical interchange magnetic reconnection event near the footpoints. With the high temporal/spatial resolution images obtained from multiple perspectives, we directly analyze the fluctuating motion of jet flow materials and explore the mechanism of fluctuation excitation during the interchange magnetic reconnection. We compare our observations with a 2.5D MHD simulation of interchange magnetic reconnection, we speculate that outward fluctuations may act as a kind of mediator between interchange magnetic reconnection and the formation process of velocity spikes/magnetic switchbacks.

How to cite: Hou, C., Rouillard, A., He, J., Gannouni, B., and Réville, V.: Possible Role of Fluctuation Excitation in the Formation of Alfvénic Fluctuations Originating from Interchange Magnetic Reconnection, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15516, https://doi.org/10.5194/egusphere-egu23-15516, 2023.

The electrons in the solar wind exhibit non-thermal velocity distribution functions. Observed non-thermal features of the electron distribution in the inner heliosphere include the field-aligned strahl, the suprathermal halo, the sunward deficit, and temperature anisotropy. These features are the result of a complex interplay between global expansion effects and local interactions between the particles and the electromagnetic fields. Global effects create, for example, the strahl via the mirror force in the decreasing magnetic field and the sunward deficit via reflections in the interplanetary electric field. Local wave-particle interactions such as instabilities change the shape of these features and thus the overall properties and moments of the electron distribution.

We discuss the science opportunities that the high-resolution data of Solar Orbiter's SWA/EAS sensor open up for unprecedented studies of the causes and effects of non-thermal electron distributions in the context of the expansion of the solar wind in the inner heliosphere. We focus, in particular, on the interplay between expansion effects and instabilities related to the electron strahl and the sunward deficit.

How to cite: Verscharen, D., Owen, C., Nicolaou, G., Coburn, J., Micera, A., and Innocenti, M. E.: Using non-thermal electron distributions to probe the inner heliosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15283, https://doi.org/10.5194/egusphere-egu23-15283, 2023.

Flare-associated particles from so-called impulsive events might be efficiently reaccelerated in gradual Solar Energetic Particle (SEP) events which are typically related to coronal mass ejections (CMEs). The existence and characteristics of such a flare-associated seed population might play a key role for understanding the high variability in particle intensity under comparable CME speeds and solar wind conditions. Understanding this variability will improve predictions of large gradual SEP events that cause a severe risk for satellite and even ground-based infrastructure. We analyze a sequence of impulsive and subsequent gradual events that occurred between 5 and 11 March 2022 and were measured in-situ with Solar Orbiter at a close distance of 0.5 AU to the Sun. We study in detail the behavior of suprathermal ions during the events and relate it to the ambient solar wind plasma properties and remote-sensing observations of the respective flares and CMEs observed from SOHO, SDO, and Solar Orbiter. We find in particular a strong local enhancement of suprathermal flare-associated ions that are trapped for several hours between two ICME structures and provide therefore a natural reservoir of seed particles that can be efficiently further accelerated in ambient compression regions or occurring shocks on their way out to 1 AU.

How to cite: Janitzek, N., Moraleda, M., Walsh, A., Mason, G., Gomez-Herrero, R., Kollhoff, A., Pacheco, D., Barcynski, K., Rodríguez-García, L., Musset, S., Hayes, L., Zouganelis, I., Ho, G., Wimmer-Schweingruber, R., and Rodríguez-Pacheco, J.: Behavior of Flare-associated Suprathermal Ions at Coronal Mass Ejections observed with Solar Orbiter at 0.5 AU, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13249, https://doi.org/10.5194/egusphere-egu23-13249, 2023.

The propagation and radial evolution of energetic particle events can only be studied by multiple-point simultaneous in-situ measurement within the heliosphere.  The joint ESA/NASA Solar Orbiter mission that was launched in February 2020, is designed to study the Sun and inner heliosphere in greater detail than ever before.  The Energetic Particle Detector (EPD) investigation on Solar Orbiter is a suite of four different sensors that measure the energetic particles from slightly above solar wind energies to hundreds of MeV/nucleon. Since launched, EPD already observed numerous large solar energetic particle (SEP) and energetic storm particle (ESP) events inside of 1 au in greater temporal and spectral resolutions than ever before.  Many of these events were also measured by spacecraft at 1 au such as ACE and/or STEREO. 

On April 2, 2022, an active region (AR 12975) on the western limb (W80) of the Sun produced a large SEP event and associated fast moving (>1400 km/s) coronal mass ejection (CME) and a CME-driven interplanetary shock (~1900 km/s).  During that time, the Solar Orbiter spacecraft was cruising near its perihelion distance (~0.35 au) at W109 relative to the Earth-Sun line, and the STEREO Ahead spacecraft was at E35.  Together, the particle instruments on these probes measured the SEP/ESP and the plasma and field instruments detected the associated interplanetary shock/CMEs on April 2-3, 2022.  In this paper, we report the multi-spacecraft observations of this event that were measured by Solar Orbiter, and we discuss the propagation and transport of SEPs from 0.3 to 1 au.

How to cite: Ho, G., Mason, G., Allen, R., Kouloumvakos, A., Wimmer-Schweingruber, R., Rodríguez-Pacheco, J., and Gómez-Herrero, R.: April 3, 2022 in-situ ESP event as observed by Solar Orbiter, ACE and Stereo, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4385, https://doi.org/10.5194/egusphere-egu23-4385, 2023.

With the launch of Solar Orbiter (SolO) together with STEREO A, and Wind it is again possible to study  multi-spacecraft Solar Energetic Particle (SEP) events within 1 AU. Over the timespan from July 2020 up to June 2022, we identify 44 events for which a significant increase of ∼100 keV electrons has been observed for at least two spacecraft. The maximum longitudinal separation of the two furthest spacecraft ranges from ∼17 to ∼217 degree. 

SEPs are expected to follow the Interplanetary Magnetic Field (IMF) which in zero-order approximation has the shape of Parker spirals. We investigate two different scenarios to identify the source of the widespread particle observation: (a) Particles are injected over a broad range of longitudes at the source surface without any perpendicular transport, hence by propagating along the IMF SEPs can be detected for distant observers. (b) Particles are injected over a narrow range of longitudes, but are distributed perpendicular to the nominal IMF by perpendicular diffusion. We discard events for which no unambiguously source location (e.g., flare) can be identified, or where an interplanetary coronal mass ejection is present. In order to investigate these scenarios a 2d  SEP transport model is utilized. The simulated data are compared to selected SEP observations. We developed a χ² minimization code in order to determine the most probable injection and transport parameters.

Here, we present our first modeling results for a selected number of multi-spacecraft SEP events involving SolO. Furthermore, we note that the multi-spacecraft event observation can be a result of a combination of case (a) and (b).

How to cite: Bruedern, M., Dresing, N., Heber, B., Kartavykh, Y., Kollhoff, A., Kühl, P., and Strauss, D. T.: Identifying the source of multi-spacecraft SEP events, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15579, https://doi.org/10.5194/egusphere-egu23-15579, 2023.

With the launch of Solar Orbiter (SolO) on Feb. 10th 2020, a new era of multi-spacecraft solar energetic particles (SEP) observations has started. The unique orbit of the mission allows the observation of SEP events close to the Sun (<0.28 au), which can occasionally be compared to corresponding observations made by other spacecraft at 1au. Such multi-spacecraft observations of the same event at different radial distances provide an excellent opportunity to study the radial evolution of SEP events.

In this study, we identify SEP events for which SolO and either Wind or STEREO-A had a small longitudinal separation (<15°) between their magnetic foot-points at the Sun. For all SEP events that satisfy our selection criteria we determine the onset times and rise times as well as peak fluxes and peak values of the first-order anisotropy for electrons in the energy range from ∼50−85 keV. We compare the event parameters observed at the different spacecraft regarding their radial changes. In our sample we find strong event-to-event variations in the radial dependency of all derived event parameters. For the majority of events, the peak flux and the maximum value of the first-order anisotropy decrease with increasing radial distance to the Sun, while the rise time increases with radial distance in the majority of events. The derived onset delays observed between two spacecraft were found to be too long to be explained by ideal Parker spirals in multiple events.

We present an overview of the most interesting observations and discuss the wide variability in the radial dependency of the event parameters analysed in this study.

How to cite: Kollhoff, A., Berger, L., Brüdern, M., Dresing, N., Eldrum, S., Fleth, S., Gómez-Herrero, R., Heber, B., Kühl, P., Pacheco, D., Rodríguez-García, L., Rodríguez-Pacheco, J., Wimmer-Schweingruber, R. F., and Xu, Z.: Multi-spacecraft observations of near-relativistic electron events at different radial distances, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12027, https://doi.org/10.5194/egusphere-egu23-12027, 2023.