MHD simulations on the large-scale propagation of high-speed solar wind streams

Fuente: arXiv
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Main Author: Hofmeister, Stefan J.
Format: Preprint
Published: 2026
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author Hofmeister, Stefan J.
author_facet Hofmeister, Stefan J.
contents We investigate the propagation of high-speed solar wind streams from their origin near the Sun to 1 AU using three-dimensional magnetohydrodynamic simulations. By tracking both global stream structure and individual plasma parcels, we assess how local in-situ measurements relate to the underlying plasma evolution. We find that high-speed streams are not parcel-preserving structures: commonly used diagnostics such as peak velocity, density, or temperature do not trace fixed plasma elements, and feature-based radial trends can therefore misrepresent the true evolution. Instead, velocity-based relationships provide a more robust framework for linking plasma parcels across heliocentric distances. Stream evolution is dominated by interaction regions, where compression leads to deceleration of fast wind, acceleration of slow wind, and significant heating. A boundary layer forms close to the Sun and can dominate narrow streams, biasing in-situ measurements toward lower apparent velocities. We show that three-dimensional transport, in particular latitudinal flows, redistributes mass and magnetic flux and reduces center-to-flank contrasts. While radial magnetic flux is conserved, the total field strength is not in spherical sampling geometries due to non-radial components. Finally, observed stream properties and geoeffectivity depend strongly on sampling location, stream geometry, and latitudinal magnetic deflection, introducing systematic variability and asymmetries in geomagnetic response.
format Preprint
id arxiv_https___arxiv_org_abs_2605_01613
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle MHD simulations on the large-scale propagation of high-speed solar wind streams
Hofmeister, Stefan J.
Solar and Stellar Astrophysics
Plasma Physics
We investigate the propagation of high-speed solar wind streams from their origin near the Sun to 1 AU using three-dimensional magnetohydrodynamic simulations. By tracking both global stream structure and individual plasma parcels, we assess how local in-situ measurements relate to the underlying plasma evolution. We find that high-speed streams are not parcel-preserving structures: commonly used diagnostics such as peak velocity, density, or temperature do not trace fixed plasma elements, and feature-based radial trends can therefore misrepresent the true evolution. Instead, velocity-based relationships provide a more robust framework for linking plasma parcels across heliocentric distances. Stream evolution is dominated by interaction regions, where compression leads to deceleration of fast wind, acceleration of slow wind, and significant heating. A boundary layer forms close to the Sun and can dominate narrow streams, biasing in-situ measurements toward lower apparent velocities. We show that three-dimensional transport, in particular latitudinal flows, redistributes mass and magnetic flux and reduces center-to-flank contrasts. While radial magnetic flux is conserved, the total field strength is not in spherical sampling geometries due to non-radial components. Finally, observed stream properties and geoeffectivity depend strongly on sampling location, stream geometry, and latitudinal magnetic deflection, introducing systematic variability and asymmetries in geomagnetic response.
title MHD simulations on the large-scale propagation of high-speed solar wind streams
topic Solar and Stellar Astrophysics
Plasma Physics
url https://arxiv.org/abs/2605.01613