Modeling and forecasting the background solar wind with data-driven physics-based models

Author(s):  
Michael Lavarra ◽  
Rui Pinto ◽  
Alexis Rouillard ◽  
Athanasios Kouloumvakos ◽  
Alessandro Bemporad ◽  
...  

<p>The quasi-steady solar wind flow is a key component of space weather, being the source of corotating density structures that perturb planetary atmospheres and affect the propagation of impulsive perturbations (such as CME). Fast and slow wind streams develop at different places in the solar atmosphere, reflecting the global distribution of the coronal magnetic field during solar cycle and its consequences for heat and mass transport across the corona. I will present recent advances on global solar wind simulations that provides robust and fully physics-based predictions of the structure and physical parameters of the solar wind based on a multi-1D approach (MULTI-VP, ISAM). Such advances relate to the driving the models with time-dependant magnetogram data, to the inclusion of transient heating phenomena, and to switching from a fluid to a multi-species description of the solar wind. The model was also driven by daily synchronic magnetograms (ADAPT) for a full solar rotation and the simulation results were compared to UVCS plane-of-sky data.The simulations produce a large range of synthetic observables (e.g multi-spacecraft in-situ measurements, white-light and EUV imagery) meant to be compared to data from current and future missions (e.g Solar Orbiter and Parker Solar Probe), and to establish physiccal connections between remote observation of the solar surface and corona and the interplanetary medium.</p>

2021 ◽  
Author(s):  
Thomas Wiegelmann ◽  
Thomas Neukirch ◽  
Iulia Chifu ◽  
Bernd Inhester

<p>Computing the solar coronal magnetic field and plasma<br>environment is an important research topic on it's own right<br>and also important for space missions like Solar Orbiter to<br>guide the analysis of remote sensing and in-situ instruments.<br>In the inner solar corona plasma forces can be neglected and<br>the field is modelled under the assumption of a vanishing<br>Lorentz-force. Further outwards (above about two solar radii)<br>plasma forces and the solar wind flow has to be considered.<br>Finally in the heliosphere one has to consider that the Sun<br>is rotating and the well known Parker-spiral forms.<br>We have developed codes based on optimization principles<br>to solve nonlinear force-free, magneto-hydro-static and<br>stationary MHD-equilibria. In the present work we want to<br>extend these methods by taking the solar rotation into account.</p>


2000 ◽  
Vol 7 (3/4) ◽  
pp. 201-210 ◽  
Author(s):  
H. K. Biernat ◽  
N. V. Erkaev ◽  
C. J. Farrugia ◽  
D. F. Vogl ◽  
W. Schaffenberger

Abstract. The study of the interaction of the solar wind with magnetized and unmagnetized planets forms a central topic of space research. Focussing on planetary magnetosheaths, we review some major developments in this field. Magnetosheath structures depend crucially on the orientation of the interplanetary magnetic field, the solar wind Alfvén Mach number, the shape of the obstacle (axisymmetric/non-axisymmetric, etc.), the boundary conditions at the magnetopause (low/high magnetic shear), and the degree of thermal anisotropy of the plasma. We illustrate the cases of Earth, Jupiter and Venus. The terrestrial magnetosphere is axisymmetric and has been probed in-situ by many spacecraft. Jupiter's magnetosphere is highly non-axisymmetric. Furthermore, we study magnetohydrodynamic effects in the Venus magnetosheath.


2021 ◽  
Author(s):  
Benoit Lavraud ◽  
Rui Pinto ◽  
Rungployphan Kieokaew ◽  
Evangelia Samara ◽  
Stefaan Poedts ◽  
...  

<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>


2020 ◽  
Author(s):  
Rui Pinto ◽  
Rungployphan Kieokaew ◽  
Benoît Lavraud ◽  
Vincent Génot ◽  
Myriam Bouchemit ◽  
...  

<p>We present the solar wind forecast module to be implemented on the Sun – interplanetary space – Earth’s magnetosphere chain of the H2020 SafeSpace project. The wind modelling pipeline, developed at the IRAP, performs real-time robust simulations (forward modelling) of the physical processes that determine the state of the solar wind from the surface of the Sun up to the L1 point. The pipeline puts together different mature research models: determination of the background coronal magnetic field, computation of many individual solar wind acceleration profiles (1 to 90 solar radii), propagation across the heliosphere and formation of CIRs (up to 1 AU or more), estimation of synthetic diagnostics (white-light and EUV imaging, in-situ time-series) and comparison to observations and spacecraft measurements. Different magnotograms sources (WSO, SOLIS, GONG, ADAPT) can be combined, as well as coronal field reconstruction methods (PFSS, NLFFF), wind models (MULTI-VP), and heliospheric propagation models (CDPP/AMDA 1D MHD, ENLIL, EUHFORIA). We provide a web-based service that continuously supplies a full set of bulk physical parameters (wind speed, density, temperature, magnetic field, phase speeds) of the solar wind up to 6-7 days in advance, at a time cadence compatible with space weather applications.</p>


2004 ◽  
Vol 219 ◽  
pp. 563-574
Author(s):  
Giannina Poletto

Before the advent of the Solar and Heliospheric Observatory (SOHO, launched in 1995), we had little information on how coronal plasma gets accelerated to the high speed measured in situ. The Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO, acquiring UV data over the first few solar radii, a region unexplored in this spectral range, allowed us to build a profile of the outflow plasma speed vs. heliocentric distance, based on empirical constraints. Still, much has to be learnt about the behavior of solar wind in the extended corona. In the following, after briefly reviewing the general properties of the solar wind, I'll focus on controversial issues — like the identification of the sources of fast and slow wind, and the acceleration of fast vs. slow wind streams — and I'll illustrate recent contributions to the solution of these problems.


2011 ◽  
Vol 7 (S286) ◽  
pp. 210-214 ◽  
Author(s):  
Sarah E. Gibson ◽  
Liang Zhao

AbstractThe recent minimum was unusually long, and it was not just the case of the “usual story” slowed down. The coronal magnetic field never became completely dipolar as in recent Space Age minima, but rather gradually evolved into an (essentially axisymmetric) global configuration possessing mixed open and closed magnetic structures at many latitudes. In the process, the impact of the solar wind at the Earth went from resembling that from a sequence of rotating “fire-hoses” to what might be expected from a weak, omnidirectional “lawn-sprinkler”. The previous (1996) solar minimum was a more classic dipolar configuration, and was characterized by slow wind of hot origin localized to the heliospheric current sheet, and fast wind of cold origin emitted from polar holes, but filling most of the heliosphere. In contrast, the more recent minimum solar wind possessed a broad range of speeds and source temperatures (although cooler overall than the prior minimum). We discuss possible connections between these observations and the near-radial expansion and small spatial scales characteristic of the recent minimum's porcupine-like magnetic field.


2020 ◽  
Author(s):  
Thomas Wiegelmann ◽  
Thomas Neukirch ◽  
Dieter Nickeler ◽  
Iulia Chifu

<p>Knowledge about the magnetic field and plasma environment is important<br>for almost all physical processes in the solar atmosphere. Precise<br>measurements of the magnetic field vector are done routinely only in<br>the photosphere, e.g. by SDO/HMI. These measurements are used as<br>boundary condition for modelling the solar chromosphere and corona,<br>whereas some model assumptions have to be made. In the low-plasma-beta<br>corona the Lorentz-force vanishes and the magnetic field<br>is reconstructed with a nonlinear force-free model. In the mixed-beta<br>chromosphere plasma forces have to be taken into account with the<br>help of a magnetostatic model. And finally for modelling the global<br>corona far beyond the source surface the solar wind flow has to<br>be incorporated within a stationary MHD model.<br>To do so, we generalize a nonlinear force-free and magneto-static optimization<br>code by the inclusion of a field aligned compressible plasma flow.<br>Applications are the implementation of the solar wind on<br>global scale. This allows to reconstruct the coronal magnetic field further<br>outwards than with potential field, nonlinear force-free and magneto-static models.<br>This way the model might help in future to provide the magnetic connectivity<br>for joint observations of remote sensing and in-situ instruments on Solar<br>Orbiter and Parker Solar Probe.</p>


Author(s):  
Allan R Macneil ◽  
Mathew J Owens ◽  
Robert T Wicks ◽  
Mike Lockwood

Abstract In its first encounter at solar distances as close as r = 0.16AU, Parker Solar Probe (PSP) observed numerous local reversals, or inversions, in the heliospheric magnetic field (HMF), which were accompanied by large spikes in solar wind speed. Both solar and in situ mechanisms have been suggested to explain the existence of HMF inversions in general. Previous work using Helios 1, covering 0.3–1AU, observed inverted HMF to become more common with increasing r, suggesting that some heliospheric driving process creates or amplifies inversions. This study expands upon these findings, by analysing inversion-associated changes in plasma properties for the same large data set, facilitated by observations of ‘strahl’ electrons to identify the unperturbed magnetic polarity. We find that many inversions exhibit anti-correlated field and velocity perturbations, and are thus characteristically Alfvénic, but many also depart strongly from this relationship over an apparent continuum of properties. Inversions depart further from the ‘ideal’ Alfvénic case with increasing r, as more energy is partitioned in the field, rather than the plasma, component of the perturbation. This departure is greatest for inversions with larger density and magnetic field strength changes, and characteristic slow solar wind properties. We find no evidence that inversions which stray further from ‘ideal’ Alfvénicity have different generation processes from those which are more Alfvénic. Instead, different inversion properties could be imprinted based on transport or formation within different solar wind streams.


2021 ◽  
Author(s):  
Zdeněk Němeček ◽  
Tereza Ďurovcová ◽  
Jana Šafránková ◽  
John D. Richardson ◽  
Jiří Šimůnek ◽  
...  

<p>The solar wind non-radial velocity components observed beyond the Alfvén point are usually attributed to waves, the interaction of different streams, or other transient phenomena. However, Earth-orbiting spacecraft as well as monitors at L1 indicate systematic deviations of the wind velocity from the radial direction. Since these deviations are of the order of several degrees, the calibration of the instruments is often questioned. This paper investigates for the first time the evolution of non-radial components of the solar wind flow along the path from ≈ 0.17 to 10 AU. A comparison of observations at 1 AU with those closer to or farther from the Sun based on measurements of many spacecraft at different locations in the heliosphere (Parker Solar Probe, Helios 1 and 2, Wind, ACE, Spektr-R, ARTEMIS probes, MAVEN, Voyagers 1and 2) shows that (i) the average values of non-radial components are not zero and vary in a systematic manner with the distance from the Sun, (ii) their values significantly depend on the solar wind radial velocity, (iii) the deviation from radial direction well correlates with the cross-helicity, and (iv) the values of non-radial components peaks at 0.25 AU and gradually decreases toward zero in the outer heliosphere. Our results suggest that the difference in the propagation direction between the faster and slower winds is already established in the solar corona and is connected with the forces emitting solar wind plasma from the coronal magnetic field. The correlation with cross-helicity probably points to outward propagating Alfven waves generated in outer corona as the most probable source of observed deviations.</p>


Sign in / Sign up

Export Citation Format

Share Document