An integrated data-driven solar wind - CME numerical framework for space weather forecasting

The development of numerical models and tools which have operational space weather potential is an increasingly important area of research. This study presents recent Canadian efforts toward the development of a numerical framework for Sun-to-Earth simulations of solar wind disturbances. This modular three-dimensional (3D) simulation framework is based on a semi-empirical data-driven approach to describe the solar corona and an MHD-based description of the heliosphere. In the present configuration, the semi-empirical component uses the Potential Field Source Surface (PFSS) and Schatten Current Sheet (SCS) models to derive the coronal magnetic field based on observed magnetogram data. Using empirical relations, solar wind properties are associated with this coronal magnetic field. Together with a Coronal Mass Ejection (CME) model, this provides inner boundary conditions for a global MHD model which is used to describe interplanetary propagation of the solar wind and CMEs. The proposed MHD numerical approach makes use of advanced numerical techniques. The 3D MHD code employs a finite-volume discretization procedure with limited piecewise linear reconstruction to solve the governing partial-differential equations. The equations are solved on a body-fitted hexahedral multi-block cubed-sphere mesh and an efficient iterative Newton method is used for time-invariant simulations and an explicit time-marching scheme is applied for unsteady cases. Additionally, an efficient anisotropic block-based refinement technique provides significant reductions in the size of the computational mesh by locally refining the grid in selected directions as dictated by the flow physics. The capabilities of the framework for accurately capturing solar wind structures and forecasting solar wind properties at Earth are demonstrated. Furthermore, a comparison with previously reported results and future space weather forecasting challenges are discussed.

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PFSS-Based Solar Wind Forecast and the Radius of the Source-Surface

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317009875 ◽

2017 ◽

Vol 13 (S335) ◽

pp. 307-309

Author(s):

Ljubomir Nikolić

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Spherical Surface ◽

Solar Wind Speed ◽

Coronal Holes ◽

Coronal Magnetic Field ◽

Source Surface ◽

Field Source ◽

Forecast Models ◽

Field Lines

AbstractThe potential-field source-surface (PFSS) model of the solar corona is a widely used tool in the space weather research and operations. In particular, the PFSS model is used in solar wind forecast models which empirically associate solar wind properties with the numerically derived coronal magnetic field. In the PFSS model, the spherical surface where magnetic field lines are forced to open is typically placed at 2.5 solar radii. However, the results presented here suggest that setting this surface (the source-surface) to lower heights can provide a better agreement between observed and modelled coronal holes during the current solar cycle. Furthermore, the lower heights of the source-surface provide a better match between observed and forecasted solar wind speed.

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Relationships between a potential field-source surface model of the coronal magnetic field and properties of the solar wind at 1 AU

Journal of Geophysical Research Atmospheres ◽

10.1029/ja089ia06p03957 ◽

1984 ◽

Vol 89 (A6) ◽

pp. 3957 ◽

Cited By ~ 23

Author(s):

S. T. Suess ◽

J. M. Wilcox ◽

J. T. Hoeksema ◽

H. Henning ◽

M. Dryer

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Potential Field ◽

Coronal Magnetic Field ◽

Surface Model ◽

Source Surface ◽

Field Source

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Interplanetary conditions: lessons from this minimum

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312004802 ◽

2011 ◽

Vol 7 (S286) ◽

pp. 168-178 ◽

Cited By ~ 1

Author(s):

J. Luhmann ◽

C. O. Lee ◽

P. Riley ◽

L. K. Jian ◽

C. T. Russell ◽

...

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Solar Minimum ◽

Large Scale ◽

Coronal Magnetic Field ◽

Source Surface ◽

Field Source ◽

Mass Fluxes ◽

Solar Wind Structure ◽

Cycle 24

AbstractInterplanetary conditions during the Cycle 23-24 minimum have attracted attention because they are noticeably different than those during other minima of the space age, exhibiting more solar wind stream interaction structures in addition to reduced mass fluxes and low magnetic field strengths. In this study we consider the differences in the solar wind source regions by applying Potential Field Source Surface models of the coronal magnetic field. In particular, we consider the large scale coronal field geometry that organizes the open field region locations and sizes, and the appearance of the helmet streamer structure that is another determiner of solar wind properties. The recent cycle minimum had an extraordinarily long entry phase (the decline of Cycle 23) that made it difficult to identify when the actual miminum arrived. In particular, the late 23rd cycle was characterized by diminishing photospheric fields and complex coronal structures that took several extra years to simplify to its traditional dipolar solar minimum state. The nearly dipolar phase, when it arrived, had a duration somewhat shorter than those of the previous cycles. The fact that the corona maintained an appearance more like a solar maximum corona through most of the quiet transitional phase between Cycles 23 and 24 gave the impression of a much more complicated solar minimum solar wind structure in spite of the weaknesses of the mass flux and interplanetary field. The extent to which the Cycle 23-24 transition will affect Cycle 24, and/or represents what happens during weak cycles in general, remains to be seen.

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Space weather: the solar perspective

Living Reviews in Solar Physics ◽

10.1007/s41116-021-00030-3 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Manuela Temmer

Keyword(s):

Solar Wind ◽

Space Weather ◽

Weather Forecasting ◽

Interplanetary Space ◽

Three Dimensions ◽

Space Weather Forecasting ◽

Stereo Mission ◽

Interaction Regions ◽

Near Future ◽

First Time

AbstractThe Sun, as an active star, is the driver of energetic phenomena that structure interplanetary space and affect planetary atmospheres. The effects of Space Weather on Earth and the solar system is of increasing importance as human spaceflight is preparing for lunar and Mars missions. This review is focusing on the solar perspective of the Space Weather relevant phenomena, coronal mass ejections (CMEs), flares, solar energetic particles (SEPs), and solar wind stream interaction regions (SIR). With the advent of the STEREO mission (launched in 2006), literally, new perspectives were provided that enabled for the first time to study coronal structures and the evolution of activity phenomena in three dimensions. New imaging capabilities, covering the entire Sun-Earth distance range, allowed to seamlessly connect CMEs and their interplanetary counterparts measured in-situ (so called ICMEs). This vastly increased our knowledge and understanding of the dynamics of interplanetary space due to solar activity and fostered the development of Space Weather forecasting models. Moreover, we are facing challenging times gathering new data from two extraordinary missions, NASA’s Parker Solar Probe (launched in 2018) and ESA’s Solar Orbiter (launched in 2020), that will in the near future provide more detailed insight into the solar wind evolution and image CMEs from view points never approached before. The current review builds upon the Living Reviews article by Schwenn from 2006, updating on the Space Weather relevant CME-flare-SEP phenomena from the solar perspective, as observed from multiple viewpoints and their concomitant solar surface signatures.

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Ensemble downscaling in coupled solar wind-magnetosphere modeling for space weather forecasting

Space Weather ◽

10.1002/2014sw001064 ◽

2014 ◽

Vol 12 (6) ◽

pp. 395-405 ◽

Cited By ~ 21

Author(s):

M. J. Owens ◽

T. S. Horbury ◽

R. T. Wicks ◽

S. L. McGregor ◽

N. P. Savani ◽

...

Keyword(s):

Solar Wind ◽

Space Weather ◽

Weather Forecasting ◽

Space Weather Forecasting

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Development of a formalism for computing in situ transits of Earth-directed CMEs. Towards a forecasting tool II

10.5194/angeo-2019-163 ◽

2020 ◽

Author(s):

Pedro Corona-Romero ◽

Pete Riley

Keyword(s):

Space Weather ◽

Weather Forecasting ◽

Geomagnetic Storms ◽

Average Error ◽

Space Weather Forecasting ◽

Empirical Relations ◽

Halo Cmes ◽

Semi Empirical ◽

Analytic Models

Abstract. Earth-directed coronal mass ejections (CMEs) are of an important interest for space weather purposes, because they are precursors of the major geomagnetic storms. The geoeffectiveness of a CME mostly relies on its physical properties like magnetic field and speed. There are multiple efforts in the literature to estimate in situ transit profiles of CMEs, most of them based on numerical codes. In this work we present a semi-empirical formalism to compute in situ transit profiles of Earth-directed fast halo CMEs. Our formalism combines analytic models and empirical relations to approximate CME properties as would be seen by a spacecraft near the Earth's orbit. We use our formalism to calculate synthetic transit profiles for 10 events, including the Bastille day event and three varSITI Campaign events. Our results showed qualitative agreement with in situ measurements. Synthetic profiles of speed, magnetic intensity, density and temperature of protons had average errors of 10 %, 27 %, 46 % and 83 %, respectively. Additionally, we also computed the travel time of CME centers, with an average error of 9 %. We found that compression of CMEs by the surrounding solar wind significantly increased our uncertainties. We also outline a possible path to apply this formalism into a space weather forecasting tool.

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Global Coronal Equilibria with Solar Wind Outflow

The Astrophysical Journal ◽

10.3847/1538-4357/ac2c71 ◽

2021 ◽

Vol 923 (1) ◽

pp. 57

Author(s):

Oliver E. K. Rice ◽

Anthony R. Yeates

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Potential Field ◽

Field Model ◽

Coronal Magnetic Field ◽

Source Surface ◽

Radial Magnetic Field ◽

Similar Time ◽

Magnetic Field Model ◽

Magnetohydrodynamic Simulations

Abstract Given a known radial magnetic field distribution on the Sun’s photospheric surface, there exist well-established methods for computing a potential magnetic field in the corona above. Such potential fields are routinely used as input to solar wind models, and to initialize magneto-frictional or full magnetohydrodynamic simulations of the coronal and heliospheric magnetic fields. We describe an improved magnetic field model that calculates a magneto-frictional equilibrium with an imposed solar wind profile (which can be Parker’s solar wind solution, or any reasonable equivalent). These “outflow fields” appear to approximate the real coronal magnetic field more closely than a potential field, take a similar time to compute, and avoid the need to impose an artificial source surface. Thus they provide a practical alternative to the potential field model for initializing time-evolving simulations or modeling the heliospheric magnetic field. We give an open-source Python implementation in spherical coordinates and apply the model to data from solar cycle 24. The outflow tends to increase the open magnetic flux compared to the potential field model, reducing the well-known discrepancy with in situ observations.

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Influence of the CME orientation on the ICME propagation

10.5194/egusphere-egu21-2526 ◽

2021 ◽

Author(s):

Karmen Martinić ◽

Mateja Dumbović ◽

Bojan Vršnak

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Weather Forecasting ◽

Flux Rope ◽

Meridional Plane ◽

Space Weather Forecasting ◽

In Situ Data ◽

Time Period ◽

Ambient Solar Wind

Beyond certain distance the ICME propagation becomes mostly governed by the interaction of the ICME and the ambient solar wind. Configuration of the interplanetary magnetic field and features of the related ambient solar wind in the ecliptic and meridional plane are different. Therefore, one can expect that the inclination of the CME flux rope axis i.e. tilt, influences the propagation of the ICME itself. In order to study the relation between the tilt parameter and the ICME propagation we investigated isolated Earth-impacting CME-ICME evets in the time period from 2006. to 2014. We determined the CME tilt in the &#8220;near-Sun&#8221; environment from the 3D reconstruction of the CME, obtained by the Graduated Cylindrical Shell model using coronagraphic images provided by the STEREO and SOHO missions. We determined the tilt of the ICME in the &#8220;near-Earth&#8221; environment using in-situ data. We constrained our study to CME-ICME events that show no evidence of rotation while propagating, i.e. have a similar tilt in the &#8220;near-Sun&#8221; and &#8220;near-Earth&#8221; environment. We present preliminary results of our study and discuss their implications for space-weather forecasting using the drag-based(ensemble) [DB(E)M] model of heliospheric propagation.

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Development of a formalism for computing in situ transits of Earth-directed CMEs – Part 2: Towards a forecasting tool

Annales Geophysicae ◽

10.5194/angeo-38-657-2020 ◽

2020 ◽

Vol 38 (3) ◽

pp. 657-681

Author(s):

Pedro Corona-Romero ◽

Pete Riley

Keyword(s):

Space Weather ◽

Weather Forecasting ◽

Geomagnetic Storms ◽

Average Error ◽

Space Weather Forecasting ◽

Empirical Relations ◽

Halo Cmes ◽

Semi Empirical ◽

Analytic Models

Abstract. Earth-directed coronal mass ejections (CMEs) are of particular interest for space weather purposes, because they are precursors of major geomagnetic storms. The geoeffectiveness of a CME mostly relies on its physical properties like magnetic field and speed. There are multiple efforts in the literature to estimate in situ transit profiles of CMEs, most of them based on numerical codes. In this work we present a semi-empirical formalism to compute in situ transit profiles of Earth-directed fast halo CMEs. Our formalism combines analytic models and empirical relations to approximate CME properties as would be seen by a spacecraft near Earth's orbit. We use our formalism to calculate synthetic transit profiles for 10 events, including the Bastille Day event and 3 varSITI Campaign events. Our results show qualitative agreement with in situ measurements. Synthetic profiles of speed, magnetic intensity, density, and temperature of protons have average errors of 10 %, 27 %, 46 %, and 83 %, respectively. Additionally, we also computed the travel time of CME centers, with an average error of 9 %. We found that compression of CMEs by the surrounding solar wind significantly increased our uncertainties. We also outline a possible path to apply this formalism in a space weather forecasting tool.

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Three-dimensional reconstruction of an expanding shock associated with a Solar particle event

10.5194/egusphere-egu21-12154 ◽

2021 ◽

Author(s):

Federica Frassati ◽

Monica Laurenza ◽

Alessandro Bemporad ◽

Matthew J. West ◽

Salvatore Mancuso ◽

...

Keyword(s):

Magnetic Field ◽

3D Reconstruction ◽

Ultra Violet ◽

Coronal Magnetic Field ◽

Release Time ◽

Shock Acceleration ◽

Source Surface ◽

Type Ii ◽

Field Source ◽

The Magnetic Field

On 2013 June 21st an eruption occurred in the active region NOAA 1177 (14S73E), giving rise to a M2.9 class flare starting at 02:30 UT, a fast partial halo coronal mass ejection (CME), and a type II radio burst. The concomitant emission of solar energetic particles (SEPs) produced a significant increase in the proton fluxes measured by LET and HET aboard STEREO-B. By using stereoscopic observations in extreme ultra violet (EUV) and white light (WL) spectral intervals, we performed a 3D reconstruction of the expanding front by processing SDO/AIA, STEREO/EUVI, COR1 and COR2, and SOHO/LASCO data assuming a spheroidal model. By using the 3D reconstruction, we estimated the temporal evolution of &#952;Bn,&#160;i.e., the angle between the normal to the expanding front and the coronal magnetic field computed by the Potential-Field Source-Surface (PFSS) approximation, within 2.5 R&#664;.&#160;The front of the CMEwas found to be quasi-parallel to the magnetic field almost everywhere.&#160;Above 2.5 R&#664;, where the front was identified as a shock, we projected the 3D expanding surface reconstructed for different times on the ecliptic plane and&#160;we calculated the &#952;Bn&#160;between the normal to the front and Parker spiral arms. In this case the shock was almost perpendicular to the magnetic field (quasi-parallel shock).&#160;During the expansion the region located between the nose and the eastern flank of the shock was magnetically connected with ST-B in agreement with the significant SEP flux measured on-board this spacecraft. While the shock was only marginally connected with ST-A and GOES-15. The SEP release time was estimated to be 10 minutes after the Type II onset, when the shock front was already above 2.5 R&#664;&#160;with a quasi-parallel configuration. Our results are discussed in the framework of the shock acceleration scenario, even if quasi-parallel shocks are expected to have a reduced acceleration efficiency.

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