Three-Dimensional MHD Modeling of Interplanetary Solar Wind Using Self-Consistent Boundary Condition Obtained from Multiple Observations and Machine Learning

Three-dimensional (3-d) magnetohydrodynamics (MHD) modeling is a key method for studying the interplanetary solar wind. In this paper, we introduce a new 3-d MHD solar wind model driven by the self-consistent boundary condition obtained from multiple observations and the Artificial Neural Network (ANN) machine learning technique. At the inner boundary, the magnetic field is derived using the magnetogram and potential field source surface extrapolation; the electron density is derived from the polarized brightness (pB) observations, the velocity can be deduced by an ANN using both the magnetogram and pB observations, and the temperature is derived from the magnetic field and electron density by a self-consistent method. Then, the 3-d interplanetary solar wind from CR2057 to CR2062 is modeled by the new model with the self-consistent boundary conditions. The modeling results present various observational characteristics at different latitudes, and are in better agreement with both the OMNI and Ulysses observations compared to our previous MHD model based only on photospheric magnetic field observations.

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Prominence Oscillations and the Influence of the Distant Photosphere

International Astronomical Union Colloquium ◽

10.1017/s0252921100047485 ◽

1998 ◽

Vol 167 ◽

pp. 147-150

Author(s):

N.A.J. Schutgens ◽

M. Kuperus ◽

G.H.J. van den Oord

Keyword(s):

Magnetic Field ◽

Boundary Condition ◽

The Other ◽

Forced Oscillations ◽

Crossing Time ◽

Self Consistent ◽

Normal Polarity ◽

The Stability ◽

The Magnetic Field ◽

Flux Conservation

AbstractWe model vertical prominence dynamics, describing the evolution of the magnetic field in a self-consistent way. Since the photosphere imposes a boundary condition on the field (flux conservation), the Alfvén crossing time τ0/2 between prominence and photosphere has to be taken into account. Using an electrodynamical description of the prominence we are able to compare two basic prominence models: Normal Polarity (NP) and Inverse Polarity (IP).The results indicate that for IP prominences, the stability properties are sensitive to ωτ0 (ω: oscillation frequency of prominence). For ωτ0 ≳ 1 instability results. Forced oscillations of five minutes are efficiently excited in IP prominences that meet certain criteria only. NP prominences on the other hand, are insensitive to the Alfvén crossing time. Forced oscillations of five minutes are difficult to excite in NP prominences.

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Predicting geo-effectiveness of CMEs using a novel 3D CME model FRi3D integrated into EUHFORIA

10.5194/egusphere-egu21-11605 ◽

2021 ◽

Author(s):

Stefaan Poedts ◽

Anwesha Maharana ◽

Camilla Scolini ◽

Alexey Isavnin

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Field Strength ◽

Magnetic Field Strength ◽

Three Dimensional ◽

Flux Rope ◽

Future Perspective ◽

The European Union ◽

Horizon 2020 ◽

The Magnetic Field

Previous studies of Coronal Mass Ejections (CMEs) have shown the importance of understanding their geometrical structure and internal magnetic field configuration for improving forecasting at Earth. The precise prediction of the CME shock and the magnetic cloud arrival time, their magnetic field strength and the orientation upon impact at Earth is still challenging and relies on solar wind and CME evolution models and precise input parameters. In order to understand the propagation of CMEs in the interplanetary medium, we need to understand their interaction with the complex features in the magnetized background solar wind which deforms, deflects and erodes the CMEs and determines their geo-effectiveness. Hence, it is important to model the internal magnetic flux-rope structure in the CMEs as they interact with CIRs/SIRs, other CMEs and solar transients in the heliosphere. The spheromak model (Verbeke et al. 2019) in the heliospheric wind and CME evolution simulation EUHFORIA (Pomoell and Poedts, 2018), fits well with the data near the CME nose close to its axis but fails to predict the magnetic field in CME legs when these impact Earth (Scolini et al. 2019). Therefore, we implemented the FRi3D stretched flux-rope CME model (Isavnin, 2016) in EUHFORIA to model a more realistic CME geometry. Fri3D captures the three-dimensional magnetic field structure with parameters like skewing, pancaking and flattening that quantify deformations experienced by an interplanetary CME. We perform test runs of real CME events and validate the ability of FRi3D coupled with EUHFORIA in predicting the CME geo-effectiveness. We have modeled two real events with FRi3D. First, a CME event on 12 July 2012 which was a head-on encounter at Earth. Second, the flank CME encounter of 14 June 2012 which did not leave any magnetic field signature at Earth when modeled with Spheromak. We compare our results with the results from non-magnetized cone simulations and magnetized simulations employing the spheromak flux-rope model. We further discuss how constraining observational parameters using the stretched flux rope CME geometry in FRi3D affects the prediction of the magnetic field strength in our simulations, highlighting improvements and discussing future perspective.This research has received funding from the European Union&#8217;s Horizon 2020 research and innovation programme under grant agreement No 870405 (EUHFORIA 2.0)

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Three-dimensional MHD simulation of CMEs in three-dimensional background solar wind with the self-consistent structure on the source surface as input: Numerical simulation of the January 1997 Sun-Earth connection event

Journal of Geophysical Research Atmospheres ◽

10.1029/2006ja012164 ◽

2007 ◽

Vol 112 (A6) ◽

pp. n/a-n/a ◽

Cited By ~ 32

Author(s):

Fang Shen ◽

Xueshang Feng ◽

S. T. Wu ◽

Changqing Xiang

Keyword(s):

Numerical Simulation ◽

Solar Wind ◽

Three Dimensional ◽

The Self ◽

Source Surface ◽

Mhd Simulation ◽

Self Consistent ◽

Earth Connection

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Determining whether the squashing factor, Q, would be a good indicator of reconnection in a resistive MHD experiment devoid of null points

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936832 ◽

2020 ◽

Vol 633 ◽

pp. A92

Author(s):

J. Reid ◽

C. E. Parnell ◽

A. W. Hood ◽

P. K. Browning

Keyword(s):

Magnetic Field ◽

Magnetic Reconnection ◽

Coronal Loop ◽

Ohmic Heating ◽

Three Dimensional ◽

Necessary And Sufficient Condition ◽

Geometric Measure ◽

Self Consistent ◽

Necessary And Sufficient ◽

The Magnetic Field

The squashing factor of a magnetic field, Q, is commonly used as an indicator of magnetic reconnection, but few studies seek to evaluate how reliable it is in comparison with other possible reconnection indicators. By using a full, self-consistent, three-dimensional, resistive magnetohydrodynamic experiment of interacting magnetic strands constituting a coronal loop, Q and several different quantities are determined. Each is then compared with the necessary and sufficient condition for reconnection, namely the integral along a field line of the component of the electric field parallel to the magnetic field. Among the reconnection indicators explored, we find the squashing factor less successful when compared with alternatives, such as Ohmic heating. In a reconnecting magnetic field devoid of null points, our work suggests that Q, being a geometric measure of the magnetic field, is not a reliable indicator of the onset or a diagnostic of the location of magnetic reconnection in some configurations.

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On the perturbation of a plasma and particle collection by a cylinder in a magnetic field

Journal of Plasma Physics ◽

10.1017/s0022377800007947 ◽

1973 ◽

Vol 10 (3) ◽

pp. 383-396 ◽

Cited By ~ 6

Author(s):

J. P. Lafon

Keyword(s):

Magnetic Field ◽

Boundary Value Problem ◽

Spatial Variation ◽

Poisson Equation ◽

Point Of View ◽

The Self ◽

Magnetized Plasma ◽

Particle Collection ◽

Self Consistent ◽

The Magnetic Field

The inhomogeneous sheath that surrounds a probe immersed in a weakly collisional magnetized plasma is investigated from the microscopic point of view, in the case when the probe is cylindrical and parallel to the magnetic field. Arbitrary surface effects of the probe (such as absorption, reflexion and emission of particles) are taken into account. The sheath is described with a model based on the solution of a boundary-value problem for the self-consistent Boltzmann—Maxwell—Poisson equation. The spatial variation of the magnetic field is discussed. Typical results of numerical computations concerning the structure of the sheath and the currents collected by the probe are given and discussed.

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Three-dimensional density and compressible magnetic structure in solar wind turbulence

Annales Geophysicae ◽

10.5194/angeo-36-527-2018 ◽

2018 ◽

Vol 36 (2) ◽

pp. 527-539 ◽

Cited By ~ 6

Author(s):

Owen W. Roberts ◽

Yasuhito Narita ◽

C.-Philippe Escoubet

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Three Dimensional ◽

Field Direction ◽

Dimensional Structure ◽

Magnetic Field Direction ◽

Three Dimensional Structure ◽

Slow Wind ◽

Incompressible Turbulence ◽

The Magnetic Field

Abstract. The three-dimensional structure of both compressible and incompressible components of turbulence is investigated at proton characteristic scales in the solar wind. Measurements of the three-dimensional structure are typically difficult, since the majority of measurements are performed by a single spacecraft. However, the Cluster mission consisting of four spacecraft in a tetrahedral formation allows for a fully three-dimensional investigation of turbulence. Incompressible turbulence is investigated by using the three vector components of the magnetic field. Meanwhile compressible turbulence is investigated by considering the magnitude of the magnetic field as a proxy for the compressible fluctuations and electron density data deduced from spacecraft potential. Application of the multi-point signal resonator technique to intervals of fast and slow wind shows that both compressible and incompressible turbulence are anisotropic with respect to the mean magnetic field direction P⟂≫P∥ and are sensitive to the value of the plasma beta (β; ratio of thermal to magnetic pressure) and the wind type. Moreover, the incompressible fluctuations of the fast and slow solar wind are revealed to be different with enhancements along the background magnetic field direction present in the fast wind intervals. The differences in the fast and slow wind and the implications for the presence of different wave modes in the plasma are discussed. Keywords. Interplanetary physics (MHD waves and turbulence)

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ABLATION OF SOLID HYDROGEN IN CONTACT WITH MAGNETIZED PLASMAS : CAN THE EXTERNAL MAGNETIC FIELD BE THE UPPER LIMIT OF THE SELF CONSISTENT ELECTRIC FIELD AT THE SOLID SURFACE ?

Le Journal de Physique Colloques ◽

10.1051/jphyscol:19797217 ◽

1979 ◽

Vol 40 (C7) ◽

pp. C7-447-C7-448

Author(s):

S. Mercurio

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Electric Field ◽

Solid Surface ◽

Solid Hydrogen ◽

The Self ◽

Magnetized Plasmas ◽

Upper Limit ◽

Self Consistent

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Cluster observations of sudden impulses in the magnetotail caused by interplanetary shocks and pressure increases

Annales Geophysicae ◽

10.5194/angeo-23-609-2005 ◽

2005 ◽

Vol 23 (2) ◽

pp. 609-624 ◽

Cited By ~ 26

Author(s):

K. E. J. Huttunen ◽

J. Slavin ◽

M. Collier ◽

H. E. J. Koskinen ◽

A. Szabo ◽

...

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Dynamic Pressure ◽

Solar Wind Speed ◽

Interplanetary Shock ◽

Wind Pressure ◽

Shock Propagation ◽

Interplanetary Shocks ◽

Maximum Variance ◽

The Magnetic Field

Abstract. Sudden impulses (SI) in the tail lobe magnetic field associated with solar wind pressure enhancements are investigated using measurements from Cluster. The magnetic field components during the SIs change in a manner consistent with the assumption that an antisunward moving lateral pressure enhancement compresses the magnetotail axisymmetrically. We found that the maximum variance SI unit vectors were nearly aligned with the associated interplanetary shock normals. For two of the tail lobe SI events during which Cluster was located close to the tail boundary, Cluster observed the inward moving magnetopause. During both events, the spacecraft location changed from the lobe to the magnetospheric boundary layer. During the event on 6 November 2001 the magnetopause was compressed past Cluster. We applied the 2-D Cartesian model developed by collier98 in which a vacuum uniform tail lobe magnetic field is compressed by a step-like pressure increase. The model underestimates the compression of the magnetic field, but it fits the magnetic field maximum variance component well. For events for which we could determine the shock normal orientation, the differences between the observed and calculated shock propagation times from the location of WIND/Geotail to the location of Cluster were small. The propagation speeds of the SIs between the Cluster spacecraft were comparable to the solar wind speed. Our results suggest that the observed tail lobe SIs are due to lateral increases in solar wind dynamic pressure outside the magnetotail boundary.

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Solar wind and substorm excitation of the wavy current sheet

Annales Geophysicae ◽

10.5194/angeo-27-2457-2009 ◽

2009 ◽

Vol 27 (6) ◽

pp. 2457-2474 ◽

Cited By ~ 25

Author(s):

C. Forsyth ◽

M. Lester ◽

R. C. Fear ◽

E. Lucek ◽

I. Dandouras ◽

...

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Current Sheet ◽

Pressure Pulse ◽

Wind Pressure ◽

Expansion Velocity ◽

Solar Wind Pressure ◽

Wave Models ◽

Best Fit ◽

The Magnetic Field

Abstract. Following a solar wind pressure pulse on 3 August 2001, GOES 8, GOES 10, Cluster and Polar observed dipolarizations of the magnetic field, accompanied by an eastward expansion of the aurora observed by IMAGE, indicating the occurrence of two substorms. Prior to the first substorm, the motion of the plasma sheet with respect to Cluster was in the ZGSM direction. Observations following the substorms show the occurrence of current sheet waves moving predominantly in the −YGSM direction. Following the second substorm, the current sheet waves caused multiple current sheet crossings of the Cluster spacecraft, previously studied by Zhang et al. (2002). We further this study to show that the velocity of the current sheet waves was similar to the expansion velocity of the substorm aurora and the expansion of the dipolarization regions in the magnetotail. Furthermore, we compare these results with the current sheet wave models of Golovchanskaya and Maltsev (2005) and Erkaev et al. (2008). We find that the Erkaev et al. (2008) model gives the best fit to the observations.

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