Conveners
CD2 - All about the solar wind: Orals - Part 1
- Stephan G. Heinemann (University of Graz, Institute of Physics)
CD2 - All about the solar wind: Orals - Part 2
- Eleanna Asvestari (University of Helsinki)
- Stephan G. Heinemann (University of Graz, Institute of Physics)
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...
Comets are directly influenced by the solar wind and one of the most spectacular interactions is a tail disconnection event. This can occur when a solar wind structure such as a CME, a faster solar wind stream or a change in magnetic field polarity (Heliospheric Current Sheet crossing) causes the tail of the comet to be completely detached from the nucleus.
Using a combination of amateur...
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...
In this work we incorporate Solar Orbiter’s Polarimetric and Helioseismic Imager (PHI)
Full Disc Telescope (FDT) observations into the Air Force Data Assimilative
Photospheric flux Transport (ADAPT) model to construct more complete global solar
photospheric maps. We feed these maps into the Wang-Sheeley-Arge (WSA) model to
reconstruct the solar corona and perform solar wind simulations for...
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...
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,...
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,...
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...
The Sun is approaching the peak of its activity in cycle 25, making space weather predictions increasingly challenging as small-scale structures on its surface evolve rapidly. In our work, we aim to better understand the solar corona so that we will better predict the solar wind, and this within an operational timing. This is especially true for the fast solar wind and at the maximum of...
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...
We present the study which aims to demonstrate that the solar wind conditions in which the CMEs propagate are critical for accurate modeling of CME and the CME-driven shock characteristics and arrival time at Earth. We analyzed two full halo coronal mass ejections (CMEs) observed on December 7, 2020 and on November 2, 2021. The first CME was propagating within the slow solar wind as seen from...
Interplanetary shocks are generated near the Sun or at distance in the heliosphere in presence of various solar events, such as coronal mass ejections or stream interaction regions, and propagate throughout the solar system. They present a sudden increase of the velocity and are generally followed by a turbulent sheath. Both aspects, the frontal shock and the following turbulent sheath,...
Coronal Mass Ejections (CMEs) are the main drivers of interplanetary shocks and space weather disturbances. CMEs propagate in the solar wind and interact with its magnetic field. This interaction can modify the CME magnetic field configuration. One of the key parameters that determines the geo-effectiveness of the CME is its internal magnetic configuration. Strong CMEs directed towards Earth...
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...
We investigate the long-term variability of Jupiter’s 3-micron methane and ethane polar emissions in relation to solar wind fluxes. Our analysis is based on 3-micron emission measurements obtained with the Gemini infrared spectrograph in 2013, 2018, 2020, 2021, and 2022, along with solar wind fluxes propagated to Jupiter’s orbit for the same years. The goal is to examine whether yearly changes...
