Conveners
CD2 - All about the solar wind: Orals - Part 1
- Eleanna Asvestari (University of Helsinki)
- Stephan G. Heinemann (University of Graz, Institute of Physics)
CD2 - All about the solar wind: Orals - Part 2
- Stephan G. Heinemann (University of Graz, Institute of Physics)
- Eleanna Asvestari (University of Helsinki)
CD2 - All about the solar wind: Orals - Part 3
- Eleanna Asvestari (University of Helsinki)
- Stephan G. Heinemann (University of Graz, Institute of Physics)
Description
The structure of the heliospheric background solar wind is shaped by the interaction between slow and fast wind streams. These interactions give rise to stream interaction regions (SIRs) and co-rotating interaction regions (CIRs), which can lead to shocks, compression- and rarefaction regions—key contributors to minor and moderate geomagnetic activity.
A deep understanding of solar wind dynamics, along with the surrounding magnetic field and their origins, is essential for improving the accuracy of space weather predictions.
This session focuses on current research related to the origin, evolution, and space weather effects of slow and fast solar wind. Observations from recent missions like the Parker Solar Probe (PSP) and Solar Orbiter (SolO), along with long-standing missions such as the Solar Dynamics Observatory (SDO) and the Solar Terrestrial Relations Observatories (STEREO), provide valuable data to refine and expand our knowledge in this field.
We invite contributions exploring various topics, including the sources and acceleration mechanisms of slow and fast solar wind, stream interactions, and the magnetic and plasma structure at the source surface and in the inner heliosphere. Additionally, we welcome studies that integrate observational data with modeling to advance our understanding of solar and heliospheric physics in the context of space weather forecasting.
The solar wind is an uninterrupted flow of highly ionised plasma that streams from compact sources at or near the Sun and expands into the whole interplanetary space, being a major driver of space weather phenomena. Understanding the conditions that regulate the formation of the solar wind, its acceleration across the corona, and its transition to the heliospheric propagation regime is key...
Periodic density structures (PDSs) are a type of solar wind mesoscale structure characterised by quasi-periodic variations in the density of the solar wind ranging from a few minutes to a few hours. They are trains of advected density structures with radial length scales of LR =100-10,000 Mm. Analysis of case studies shows that PDSs can be compressed when embedded in a stream interaction...
Stream Interaction Regions (SIRs) are large-scale interplanetary structures that evolve radially outward from the Sun. They are formed when a fast solar wind stream overtakes a slower stream ahead of it, leading to the development of compressed plasma and magnetic fields. These regions are known to cause decreases in galactic cosmic ray (GCR) intensity, both at Earth's surface and in...
The ambient solar corona and solar wind plays an essential role in space weather at Earth and throughout the solar system. The magnetic field is a key aspect of describing the solar wind ambient state, and solar wind properties are closely tied to magnetic structure. The field is most readily measured in the photosphere, so models must extrapolate this field out into the solar wind. We...
The validation of the 3D MHD model EUHFORIA (EUropean Heliospheric FORecasting Information Asset, Pomoell & Poedts, 2018) at near-Sun distances was made possible with the availability of solar wind data from the Parker Solar Probe (PSP) mission. We carried out solar wind simulations for the first ten perihelion encounters by PSP, each covering a period of approximately three weeks and spanning...
Modeling of the corona and solar wind is challenging, as it is highly dependent on global photospheric magnetic field maps, which serve as the boundary conditions to all coronal models that drive solar wind models. Unfortunately, less than half of the Sun’s photospheric magnetic field is reliably measured from any given vantage point and thus it is common for the maps to have highly dated and...
Solar wind at L1 is modelled by coupling two independent and agnostic domains of the corona and heliosphere. The transition between the two domains occurs when the solar wind becomes supersonic and super-Alfvenic. The heliospheric solar wind is then driven with appropriate boundary conditions at 0.1 AU which are derived from a coronal model. A popular choice for defining the boundary...
Turbulence in plasmas involves a complex cross-scale coupling of fields and distortions of particle velocity distributions, with the generation of non-thermal features. How the energy contained in the large-scale fluctuations cascades all the way down to the kinetic scales, and how such turbulence interacts with particles, remains one of the major unsolved problems in plasma physics. Moreover,...
Properties of turbulence in the interplanetary medium affect propagation of geomagnetic storm drivers such as CMEs. Magnetic reconnection in turbulent plasmas, specially at small scales, is relevant in the process of cross-scale energy transfer and energy dissipation in turbulence. Magnetic reconnection is a process in which magnetic energy dissipates, turning into kinetic and thermal energy,...
Magnetic reconnection is a fundamental process in astrophysical plasma, as it enables the dissipation of energy at kinetic scales as well as large-scale reconfiguration of the magnetic topology. In the solar wind, its quantitative role in plasma dynamics and particle energization remains an open question that is starting to come into focus as more missions now probe the inner heliosphere. In...
The solar wind is a complex and dynamic plasma environment, populated by a variety of structures. Among these we find Coronal Mass Ejections (CMEs), interplanetary shocks, Corotating Interaction Regions (CIRs) and large-amplitude non-linear deflections of the magnetic field called switchbacks. They have been shown by Parker Solar Probe to be ubiquitous (Bale et al. 2019). These switchbacks,...
Large-scale coronal structures, such as streamers and pseudostreamers, are considered potential sources of the slow solar wind, contributing to its structured nature and variability. However, due to the lack of high-resolution coronal observations, the processes driving the dynamics of these structures and their role in the slow wind are not yet fully understood. In this study, we analyzed a...
Based on in-situ measurements, this study compares two upstream solar wind regimes: at the Lagrange point L1 and near-Earth. We quantify the reliability of the OMNI dataset to represent the solar wind recorded in a near-Earth environment as an input to solar wind-magnetosphere interaction studies. In order to do this we compare the OMNI data with solar wind data directly recorded by spacecraft...
An unprecedented opportunity exists to advance heliospheric and geospace science, as well as improve space weather operations, by coordinating measurements across a constellation of current and near-term missions from NASA, NOAA, and ISRO orbiting the Lagrange 1 point. Though these missions were initially designed for diverse objectives and launched at different times, they now offer the...
Our research focuses on the evolution of sheath regions, specifically analyzing the open solar flux (OSF) and total pressure among other variables. To identify the most relevant contributions to the sheaths, we separate the total pressure into plasma and magnetic pressure components. Utilizing the extensive dataset obtained from Larrodera and Temmer (2024), we perform a detailed statistical...
Solar wind energisation and acceleration have been long-standing problems in solar physics. Oftentimes, the possibility of magnetohydrodynamic (MHD) wave energy dissipation is invoked and explored in order to understand the physical processes behind these phenomena. The ubiquitous presence of MHD waves in the solar wind has been established through various in situ and remote observations. For...
Co-rotating interaction regions (CIRs) are formed at the interface of the background slow solar wind and the fast solar wind emanating from coronal holes. Their high velocities and plasma pressures shape the heliosphere and are one of the main drivers of geomagnetic storms. The recently formed fleet of spacecraft in the heliosphere, including Parker Solar Probe, Solar Orbiter and BepiColombo,...
The presence of energetic electrons in the heliosphere is associated with solar eruptions, but details of the acceleration and transport mechanisms are still unknown. We explore how electrons interact with shock waves under the assumptions of shock drift acceleration (SDA), diffusive shock acceleration (DSA), and stochastic shock drift acceleration (SSDA). Consideration of the shock wave...
Accurate modeling of the ambient solar wind, particularly high-speed streams (HSSs), is crucial as they drive geomagnetic activity and influence the propagation of coronal mass ejections through the heliosphere. Previous solar wind (SW) validation studies have reported discrepancies between modeled and observed SW conditions at L1, indicating that a major source of discrepancies arises from...
