<p>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 –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.</p><p>Different parts of this research have received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 870405 (EUHFORIA 2.0) and grant agreement No 01004159 (SERPENTINE).</p>

<p>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 – interplanetary space – Earth’s magnetosphere. This presentation focuses on the part of the pipeline that is dedicated to the forecasting – from solar measurements – 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’s Horizon 2020 research and innovation programme under grant agreement No 870437.</p>

<p>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.</p><p><span><span><em>This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 870437 (SafeSpace).</em></span></span></p>