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The turbulent foreshock region upstream of the quasi- parallel bow shock is dominated by waves and reflected particles that interact with each other and create a large number of different foreshock phenomena. Plasma structures with enhanced magnetic field (Short Large Amplitude Magnetic Structures or SLAMS), and density spikes, named plasmoids, are frequently observed. Based on our previous results, we have found that there is a category of events exhibiting both magnetic field and density enhancements simultaneously and we introduce the term “mixed structure” for them. Using measurements of the Magnetospheric Multiscale Spacecraft (MMS) and OMNI solar wind database, we try to explore the origin of these structures, their occurrence rate and properties in association with the foreshock boundary. Moreover, we attempt to trace and observe their interaction with the bow shock, using multi-spacecraft analysis by simultaneous measurements of Cluster, THEMIS, GEOTAIL and MMS and discuss their evolution., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Spontaneous Hot Flow Anomalies (sHFAs) are a kind of foreshock transients. Unlike hot flow anomalies, they are formed in the foreshock region without a clear upstream discontinuity. Nevertheless, the features and their influence on the magnetospheric system are the same for these two types of discontinuities. Previous studies revealed that HFA and sHFA preferentially occur under radial IMF conditions. However, our preliminary investigation shows that sHFA rarely occurs during long-lasting radial IMF events. In this study, we will completely check the characteristics of various parameters in the foreshock under different IMF cone angle conditions to reveal the candidate mechanism for this disagreement., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Two basic types of solar wind are usually distinguished: fast and slow. As the fast solar wind stream propagates through the interplanetary space, it interacts with the surrounding slow streams. This interaction creates stream interaction regions at the leading and trailing edges of the fast stream. These regions are filled with a solar wind of mixed properties that do not correspond to the standard classification of the solar wind. Moreover, the solar wind parameters change significantly with increasing radial distance from the Sun. We focus on the evolution of the fast solar wind streams and their surroundings throughout the heliosphere. We combine near-Sun observations made by the Parker Solar Probe (PSP) with Solar Orbiter measurements at intermediate distances and with near-Earth data (Wind, ACE) for study of the non-radial propagation of the fast solar wind. We investigate how this feature varies for different PSP encounters and how the corresponding processes contribute to the formation of the intermediate streams within the stream interaction regions., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Solar wind turbulence is generated by various processes in the outer corona but it undergoes a rapid evolution in course of the solar wind expansion to the heliosphere. This evolution is more or less well understood from the Mercury orbit until the termination shock due to observations of Helios, Ulysses and Voyager but first Parker Solar Probe (PSP) measurements in the inner heliosphere revealed many unexpected features that need a deeper study. The paper presents the comprehensive statistical study of the evolution of compressive and non-compressive magnetic field fluctuations in the inertial and kinetic ranges of frequencies that is based on up to date available PSP data. We analyze solar wind power spectra and their general trends and compare them with Wind observations near 1 au. The first analysis revealed that turbulence is generally decaying with the increasing distance from the source but this trend changes around 0.3-0.4 AU. Moreover, some of the well-established relationships like the spectral steepening with an increasing fluctuation amplitude reverse at near the Sun. We search for possible source(s) of the enhanced fluctuations as well as for physical mechanisms responsible for spectral flattening at the high fluctuation level., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

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