An Entropy-stable Ideal EC-GLM-MHD Model for the Simulation of the Three-dimensional Ambient Solar Wind

2021 ◽  
Vol 257 (2) ◽  
pp. 24
Author(s):  
Caixia Li ◽  
Xueshang Feng ◽  
Fengsi Wei
2021 ◽  
Vol 9 ◽  
Author(s):  
Chang Liu ◽  
Fang Shen ◽  
Yousheng Liu ◽  
Man Zhang ◽  
Xiaojing Liu

In the solar coronal numerical simulation, the coronal heating/acceleration and the magnetic divergence cleaning techniques are very important. The coronal–interplanetary total variation diminishing (COIN-TVD) magnetohydrodynamic (MHD) model is developed in recent years that can effectively realize the coronal–interplanetary three-dimensional (3D) solar wind simulation. In this study, we focus on the 3D coronal solar wind simulation by using the COIN-TVD MHD model. In order to simulate the heating and acceleration of solar wind in the coronal region, the volume heating term in the model is improved efficiently. Then, the influence of the different methods to reduce the ∇⋅B constraint error on the coronal solar wind structure is discussed. Here, we choose Carrington Rotation (CR) 2199 as a study case and try to make a comparison of the simulation results among the different magnetic divergence cleaning methods, including the diffusive method, the Powell method, and the composite diffusive/Powell method, by using the 3D COIN-TVD MHD model. Our simulation results show that with the different magnetic divergence cleaning methods, the ∇⋅B error can be reduced in different levels during the solar wind simulation. Among the three divergence cleaning methods we used, the composite diffusive/Powell method can maintain the divergence cleaning constraint better to a certain extent, and the relative magnetic field divergence error can be controlled in the order of 10−9. Although these numerical simulations are performed for the background solar corona, these methods are also suitable for the simulation of CME initiation and propagation.


2020 ◽  
Vol 10 ◽  
pp. 44
Author(s):  
Huichao Li ◽  
Xueshang Feng ◽  
Fengsi Wei

For a three-dimensional magnetohydrodynamics solar wind model, it is necessary to carry out assessment studies to reveal its ability and limitation. In this paper, the ambient solar wind results of year 2008 generated by the CESE-HLLD 3D MHD model are compared with multipoint in-situ measurements during the late declining phase of solar cycle 23. The near-ecliptic results are assessed both quantitatively and qualitatively by comparing with in-situ data obtained at the L1 point and by the twin STEREO spacecraft. The assessment reveals the model’s ability in reproducing the time series and statistical characteristics of solar wind parameters, and in catching the change of interplanetary magnetic field polarity and the occurrence of the stream interaction regions. We find that the two-stream structure observed near the ecliptic plane is reproduced, but the differences among observations at L1 and the twin STEREO spacecraft are not caught by the model. The latitudinal variation of the results is assessed by comparing with the Ulysses observation. The characters of variation in different latitudinal ranges are duplicated by the model, but biases of the results are seen, and the boundary layers between fast and slow solar wind are sometimes thicker than observation.


2009 ◽  
Vol 114 (A9) ◽  
pp. n/a-n/a ◽  
Author(s):  
N. Terada ◽  
H. Shinagawa ◽  
T. Tanaka ◽  
K. Murawski ◽  
K. Terada

2019 ◽  
Vol 85 (4) ◽  
Author(s):  
Benjamin D. G. Chandran ◽  
Jean C. Perez

We present three-dimensional direct numerical simulations and an analytic model of reflection-driven magnetohydrodynamic (MHD) turbulence in the solar wind. Our simulations describe transverse, non-compressive MHD fluctuations within a narrow magnetic flux tube that extends from the photosphere, through the chromosphere and corona and out to a heliocentric distance  $r$ of 21 solar radii  $(R_{\odot })$ . We launch outward-propagating ‘ $\boldsymbol{z}^{+}$ fluctuations’ into the simulation domain by imposing a randomly evolving photospheric velocity field. As these fluctuations propagate away from the Sun, they undergo partial reflection, producing inward-propagating ‘ $\boldsymbol{z}^{-}$ fluctuations’. Counter-propagating fluctuations subsequently interact, causing fluctuation energy to cascade to small scales and dissipate. Our analytic model incorporates dynamic alignment, allows for strongly or weakly turbulent nonlinear interactions and divides the $\boldsymbol{z}^{+}$ fluctuations into two populations with different characteristic radial correlation lengths. The inertial-range power spectra of $\boldsymbol{z}^{+}$ and $\boldsymbol{z}^{-}$ fluctuations in our simulations evolve toward a $k_{\bot }^{-3/2}$ scaling at $r>10R_{\odot }$ , where $k_{\bot }$ is the wave-vector component perpendicular to the background magnetic field. In two of our simulations, the $\boldsymbol{z}^{+}$ power spectra are much flatter between the coronal base and $r\simeq 4R_{\odot }$ . We argue that these spectral scalings are caused by: (i) high-pass filtering in the upper chromosphere; (ii) the anomalous coherence of inertial-range $\boldsymbol{z}^{-}$ fluctuations in a reference frame propagating outwards with the $\boldsymbol{z}^{+}$ fluctuations; and (iii) the change in the sign of the radial derivative of the Alfvén speed at $r=r_{\text{m}}\simeq 1.7R_{\odot }$ , which disrupts this anomalous coherence between $r=r_{\text{m}}$ and $r\simeq 2r_{\text{m}}$ . At $r>1.3R_{\odot }$ , the turbulent heating rate in our simulations is comparable to the turbulent heating rate in a previously developed solar-wind model that agreed with a number of observational constraints, consistent with the hypothesis that MHD turbulence accounts for much of the heating of the fast solar wind.


2009 ◽  
Vol 114 (A10) ◽  
pp. n/a-n/a ◽  
Author(s):  
R. Kataoka ◽  
T. Ebisuzaki ◽  
K. Kusano ◽  
D. Shiota ◽  
S. Inoue ◽  
...  

2013 ◽  
Vol 56 (11) ◽  
pp. 1864-1880 ◽  
Author(s):  
XueShang Feng ◽  
DingKun Zhong ◽  
ChangQing Xiang ◽  
Yao Zhang
Keyword(s):  

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