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Entropy Stable Finite Difference Schemes for Chew, Goldberger and Low Anisotropic Plasma Flow Equations

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Abstract

In this article, we consider the Chew, Goldberger and Low (CGL) plasma flow equations, which is a set of nonlinear, non-conservative hyperbolic PDEs modeling anisotropic plasma flows. These equations incorporate the double adiabatic approximation for the evolution of the pressure, making them very valuable for plasma physics, space physics, and astrophysical applications. We first present the entropy analysis for the weak solutions. We then propose entropy-stable finite-difference schemes for the CGL equations. The key idea is to reformulate the CGL equations by rewriting some of the conservative terms in the non-conservation form. The conservative part of the reformulated equations is very similar to the magnetohydrodynamics (MHD) equations which is then symmetrized using Godunov’s symmetrization process for the MHD equations. The resulting equations are in the form where the conservative part combined with non-conservative Godunov’s terms is compatible with the entropy equation and the rest of the non-conservative terms do not contribute to the entropy equations. The final set of reformulated equations is then discretized by designing entropy conservative numerical flux and entropy diffusion operator based on the entropy scaled eigenvectors of the conservative part. We then prove the semi-discrete entropy stability of the schemes for the reformulated CGL equations. The schemes are then tested using several test problems derived from the corresponding MHD test cases.

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References

  1. Abgrall, R., Karni, S.: A comment on the computation of non-conservative products. J. Comput. Phys. 229(8), 2759–2763 (2010)

    MathSciNet  MATH  Google Scholar 

  2. Abgrall, R., Kumar, H.: Robust finite volume schemes for two-fluid plasma equations. J. Sci. Comput. 60(3), 584–611 (2014)

    MathSciNet  MATH  Google Scholar 

  3. Balsara, D.S.: The eigenstructure of the equations of radiation magnetohydrodynamics. J. Quant. Spectrosc. Radiat. Transfer 61(5), 637–646 (1999)

    MATH  Google Scholar 

  4. Balsara, D.S., Li, J., Montecinos, G.I.: An efficient, second-order accurate, universal generalized Riemann problem solver based on the HLLI Riemann solver. J. Comput. Phys. 375, 1238–1269 (2018)

    MathSciNet  MATH  Google Scholar 

  5. Barth, T.: On the role of involutions in the discontinuous galerkin discretization of maxwell and magnetohydrodynamic systems. IMA Vol. Math. Appl. 142, 69 (2006)

    MATH  Google Scholar 

  6. Barth, T.J.: Numerical methods for gasdynamic systems on unstructured meshes. In: An Introduction to Recent Developments in Theory and Numerics for Conservation Laws: Proceedings of the International School on Theory and Numerics for Conservation Laws, Freiburg/Littenweiler, October 20–24, 1997 pp. 195–285 (1999)

  7. Berthon, C.: Numerical approximations of the 10-moment gaussian closure. Math. Comput. 75(256), 1809–1831 (2006)

    MathSciNet  MATH  Google Scholar 

  8. Berthon, C., Dubroca, B., Sangam, A.: An entropy preserving relaxation scheme for ten-moments equations with source terms. Commun. Math. Sci. 13(8), 2119–2154 (2015)

    MathSciNet  MATH  Google Scholar 

  9. Bhoriya, D., Balsara, D., Florinski, V., Kumar, H.: Going beyond the mhd approximation: physics-based numerical solution of the cgl equations. Submitted (2024)

  10. Bhoriya, D., Kumar, H., Chandrashekar, P.: High-order finite-difference entropy stable schemes for two-fluid relativistic plasma flow equations. J. Comput. Phys. 488, 112207 (2023)

    MathSciNet  MATH  Google Scholar 

  11. Biswas, B., Kumar, H., Yadav, A.: Entropy stable discontinuous galerkin methods for ten-moment gaussian closure equations. J. Comput. Phys. 431, 110148 (2021)

    MathSciNet  MATH  Google Scholar 

  12. Bouchut, F., Klingenberg, C., Waagan, K.: A multi-wave approximate riemann solver for ideal mhd based on relaxation. I: theoretical framework. Numer. Math. 108, 7–42 (2007)

  13. Brio, M., Wu, C.: An upwind differencing scheme for the equations of ideal magnetohydrodynamics. J. Comput. Phys. 75(2), 400–422 (1988)

    MathSciNet  MATH  Google Scholar 

  14. Brown, S., Roe, P., Groth, C.: Numerical solution of a 10-moment model for nonequilibrium gasdynamics. In: 12th Computational Fluid Dynamics Conference, p. 1677 (1995)

  15. Burch, J., Moore, T., Torbert, R., Giles, Bh.: Magnetospheric multiscale overview and science objectives. Space Sci. Rev. 199, 5–21 (2016)

    Google Scholar 

  16. Busto, S., Dumbser, M.: A new thermodynamically compatible finite volume scheme for magnetohydrodynamics. SIAM J. Numer. Anal. 61(1), 343–364 (2023)

    MathSciNet  MATH  Google Scholar 

  17. Chandran, B.D., Dennis, T.J., Quataert, E., Bale, S.D.: Incorporating kinetic physics into a two-fluid solar-wind model with temperature anisotropy and low-frequency alfvén-wave turbulence. Astrophys. J. 743(2), 197 (2011)

    Google Scholar 

  18. Chandrashekar, P.: Kinetic energy preserving and entropy stable finite volume schemes for compressible euler and navier-stokes equations. Commun. Comput. Phys. 14(5), 1252–1286 (2013)

    MathSciNet  MATH  Google Scholar 

  19. Chandrashekar, P., Klingenberg, C.: Entropy stable finite volume scheme for ideal compressible mhd on 2-d cartesian meshes. SIAM J. Numer. Anal. 54(2), 1313–1340 (2016)

    MathSciNet  MATH  Google Scholar 

  20. Chew, G., Goldberger, M., Low, F.: The boltzmann equation and the one-fluid hydromagnetic equations in the absence of particle collisions. Proc. R. Soc. Lond. A 236(1204), 112–118 (1956)

    MathSciNet  MATH  Google Scholar 

  21. Dal Maso, G., Lefloch, P.G., Murat, F.: Definition and weak stability of nonconservative products. Journal de mathématiques pures et appliquées 74(6), 483–548 (1995)

    MathSciNet  MATH  Google Scholar 

  22. Dennis Jr, J.E., Schnabel, R.B.: Numerical methods for unconstrained optimization and nonlinear equations. SIAM (1996)

  23. Derigs, D., Winters, A.R., Gassner, G.J., Walch, S.: A novel high-order, entropy stable, 3d amr mhd solver with guaranteed positive pressure. J. Comput. Phys. 317, 223–256 (2016)

    MathSciNet  MATH  Google Scholar 

  24. Derigs, D., Winters, A.R., Gassner, G.J., Walch, S., Bohm, M.: Ideal glm-mhd: about the entropy consistent nine-wave magnetic field divergence diminishing ideal magnetohydrodynamics equations. J. Comput. Phys. 364, 420–467 (2018)

    MathSciNet  MATH  Google Scholar 

  25. Dubroca, B., Tchong, M., Charrier, P., Tikhonchuk, V., Morreeuw, J.P.: Magnetic field generation in plasmas due to anisotropic laser heating. Phys. Plasmas 11(8), 3830–3839 (2004)

    MATH  Google Scholar 

  26. Dumbser, M., Balsara, D.S.: A new efficient formulation of the hllem riemann solver for general conservative and non-conservative hyperbolic systems. J. Comput. Phys. 304, 275–319 (2016)

    MathSciNet  MATH  Google Scholar 

  27. Dumin, Y.V.: The corotation field in collisionless magnetospheric plasma and its influence on average electric field in the lower atmosphere. Adv. Space Res. 30(10), 2209–2214 (2002)

    MATH  Google Scholar 

  28. Fjordholm, U.S., Mishra, S., Tadmor, E.: Arbitrarily high-order accurate entropy stable essentially nonoscillatory schemes for systems of conservation laws. SIAM J. Numer. Anal. 50(2), 544–573 (2012)

    MathSciNet  MATH  Google Scholar 

  29. Fjordholm, U.S., Mishra, S., Tadmor, E.: Eno reconstruction and eno interpolation are stable. Found. Comput. Math. 13(2), 139–159 (2013)

    MathSciNet  MATH  Google Scholar 

  30. Fuchs, F.G., McMurry, A.D., Mishra, S., Risebro, N.H., Waagan, K.: Approximate riemann solvers and robust high-order finite volume schemes for multi-dimensional ideal mhd equations. Commun. Comput. Phys. 9(2), 324–362 (2011)

    MathSciNet  MATH  Google Scholar 

  31. Fuchs, F.G., Mishra, S., Risebro, N.H.: Splitting-based finite volume schemes for ideal mhd equations. J. Comput. Phys. 228(3), 641–660 (2009)

    MathSciNet  MATH  Google Scholar 

  32. Godlewski, E., Raviart, P.A.: Numerical approximation of hyperbolic systems of conservation laws, vol. 118. Springer Science & Business Media, Berlin (2013)

    MATH  Google Scholar 

  33. Godunov, S.K.: Symmetric form of the equations of magnetohydrodynamics. Numer. Methods Mech. Contin. Medium 1, 26–34 (1972)

    MATH  Google Scholar 

  34. Goedbloed, J.H., Poedts, S.: Principles of Magnetohydrodynamics: With Applications to Laboratory and Astrophysical Plasmas. Cambridge University Press, Cambridge (2004)

    MATH  Google Scholar 

  35. Gombosi, T.I., Rasmussen, C.E.: Transport of gyration-dominated space plasmas of thermal origin: 1. Generalized transport equations. J. Geophys. Res. Space Phys. 96(A5), 7759–7778 (1991)

  36. Gottlieb, S., Shu, C.W., Tadmor, E.: Strong stability-preserving high-order time discretization methods. SIAM Rev. 43(1), 89–112 (2001)

    MathSciNet  MATH  Google Scholar 

  37. Hakim, A., Loverich, J., Shumlak, U.: A high resolution wave propagation scheme for ideal Two-Fluid plasma equations. J. Comput. Phys. 219(1), 418–442 (2006)

    MathSciNet  MATH  Google Scholar 

  38. Hakim, A.H.: Extended mhd modelling with the ten-moment equations. J. Fus. Energy 27, 36–43 (2008)

    MATH  Google Scholar 

  39. Heinemann, M.: Role of collisionless heat flux in magnetospheric convection. J. Geophys. Res. Space Phys. 104(A12), 28397–28410 (1999)

    MATH  Google Scholar 

  40. Hirabayashi, K., Hoshino, M., Amano, T.: A new framework for magnetohydrodynamic simulations with anisotropic pressure. J. Comput. Phys. 327, 851–872 (2016)

    MathSciNet  MATH  Google Scholar 

  41. Hollweg, J.V.: Collisionless electron heat conduction in the solar wind. J. Geophys. Res. 81(10), 1649–1658 (1976)

    MATH  Google Scholar 

  42. Huang, Z., Tóth, G., van der Holst, B., Chen, Y., Gombosi, T.: A six-moment multi-fluid plasma model. J. Comput. Phys. 387, 134–153 (2019)

    MathSciNet  MATH  Google Scholar 

  43. Hunana, P., Tenerani, A., Zank, G., Khomenko, E., Goldstein, M., Webb, G., Velli, M., Adhikari, L.: A brief guide to fluid models with anisotropic temperatures part 1-cgl description and collisionless fluid hierarchy. arXiv preprint arXiv:1901.09354 (2019)

  44. Ismail, F., Roe, P.L.: Affordable, entropy-consistent euler flux functions ii: entropy production at shocks. J. Comput. Phys. 228(15), 5410–5436 (2009)

    MathSciNet  MATH  Google Scholar 

  45. Johnson, E.A.: Gaussian-moment relaxation closures for verifiable numerical simulation of fast magnetic reconnection in plasma. arXiv preprint arXiv:1409.6985 (2014)

  46. Karimabadi, H., Roytershteyn, V., Vu, H., Omelchenko, Y., Scudder, J., Daughton, W., Dimmock, A., Nykyri, K., Wan, M., Sibeck, D., et al.: The link between shocks, turbulence, and magnetic reconnection in collisionless plasmas. Phys. Plasmas (2014). https://doi.org/10.1063/1.4882875

    Article  Google Scholar 

  47. Kato, Y., Tajiri, M., Taniuti, T.: Propagation of hydromagnetic waves in collisionless plasma. i. J. Phys. Soc. Jpn. 21(4), 765–777 (1966)

  48. Kennedy, C.A., Carpenter, M.H.: Additive runge-kutta schemes for convection-diffusion-reaction equations. Appl. Numer. Math. 44(1–2), 139–181 (2003)

    MathSciNet  MATH  Google Scholar 

  49. Kumar, H., Mishra, S.: Entropy stable numerical schemes for two-fluid plasma equations. J. Sci. Comput. 52(2), 401–425 (2012)

    MathSciNet  MATH  Google Scholar 

  50. Landau, L., Lifshitz, E.: Relativistic fluid dynamics (1987)

  51. Lefloch, P.G., Mercier, J.M., Rohde, C.: Fully discrete, entropy conservative schemes of arbitraryorder. SIAM J. Numer. Anal. 40(5), 1968–1992 (2002)

    MathSciNet  MATH  Google Scholar 

  52. Meena, A.K., Kumar, H.: Robust MUSCL schemes for ten-moment Gaussian closure equations with source terms. Int. J. Finite 14, 34 (2017)

    MathSciNet  MATH  Google Scholar 

  53. Meena, A.K., Kumar, H.: A well-balanced scheme for ten-moment Gaussian closure equations with source term. Z. Angew. Math. Phys. 69(1), 8 (2017)

    MathSciNet  MATH  Google Scholar 

  54. Meena, A.K., Kumar, H.: Robust numerical schemes for two-fluid ten-moment plasma flow equations. Z. Angew. Math. Phys. 70, 1–30 (2019)

    MathSciNet  MATH  Google Scholar 

  55. Meena, A.K., Kumar, H., Chandrashekar, P.: Positivity-preserving high-order discontinuous Galerkin schemes for ten-moment Gaussian closure equations. J. Comput. Phys. 339, 370–395 (2017)

    MathSciNet  MATH  Google Scholar 

  56. Meng, X., Tóth, G., Sokolov, I.V., Gombosi, T.I.: Classical and semirelativistic magnetohydrodynamics with anisotropic ion pressure. J. Comput. Phys. 231(9), 3610–3622 (2012)

    MathSciNet  MATH  Google Scholar 

  57. Orszag, S.A., Tang, C.M.: Small-scale structure of two-dimensional magnetohydrodynamic turbulence. J. Fluid Mech. 90(1), 129–143 (1979)

    MATH  Google Scholar 

  58. Otto, A.: 3d resistive mhd computations of magnetospheric physics. Comput. Phys. Commun. 59(1), 185–195 (1990)

    MATH  Google Scholar 

  59. Pareschi, L., Russo, G.: Implicit-explicit runge-kutta schemes and applications to hyperbolic systems with relaxation. J. Sci. Comput. 25, 129–155 (2005)

    MathSciNet  MATH  Google Scholar 

  60. Roe, P.L.: Affordable, entropy consistent flux functions. In: Eleventh International Conference on Hyperbolic Problems: Theory, Numerics and Applications, Lyon (2006)

  61. Rueda-Ramírez, A.M., Sikstel, A., Gassner, G.J.: An entropy-stable discontinuous galerkin discretization of the ideal multi-ion magnetohydrodynamics system. arXiv preprint arXiv:2402.14615 (2024)

  62. Ryu, D., Jones, T.W.: Numerical magetohydrodynamics in astrophysics: algorithm and tests for one-dimensional flow. Astrophys. J. 442, 228 (1995)

    MATH  Google Scholar 

  63. Sangam, A.: An hllc scheme for ten-moments approximation coupled with magnetic field. Int. J. Comput. Sci. Math. 2(1–2), 73–109 (2008)

    MathSciNet  MATH  Google Scholar 

  64. Sen, C., Kumar, H.: Entropy stable schemes for ten-moment Gaussian closure equations. J. Sci. Comput. 75(2), 1128–1155 (2018)

    MathSciNet  MATH  Google Scholar 

  65. Tadmor, E.: Entropy stability theory for difference approximations of nonlinear conservation laws and related time-dependent problems. Acta Numer. 12, 451–512 (2003)

    MathSciNet  MATH  Google Scholar 

  66. Tóth, G.: The div b= 0 constraint in shock-capturing magnetohydrodynamics codes. J. Comput. Phys. 161(2), 605–652 (2000)

    MathSciNet  MATH  Google Scholar 

  67. Wang, L., Hakim, A.H., Ng, J., Dong, C., Germaschewski, K.: Exact and locally implicit source term solvers for multifluid-Maxwell systems. J. Comput. Phys. 415, 109510 (2020)

    MathSciNet  MATH  Google Scholar 

  68. Yadav, A., Bhoriya, D., Kumar, H., Chandrashekar, P.: Entropy stable schemes for the shear shallow water model equations. J. Sci. Comput. 97(3), 77 (2023)

    MathSciNet  MATH  Google Scholar 

  69. Zhao, X., Yang, Y., Seyler, C.E.: A positivity-preserving semi-implicit discontinuous Galerkin scheme for solving extended magnetohydrodynamics equations. J. Comput. Phys. 278, 400–415 (2014)

    MathSciNet  MATH  Google Scholar 

  70. Zouganelis, I., Maksimovic, M., Meyer-Vernet, N., Lamy, H., Issautier, K.: A transonic collisionless model of the solar wind. Astrophys. J. 606(1), 542 (2004)

    MATH  Google Scholar 

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Funding

The work of Harish Kumar is supported in parts by VAJRA grant No. VJR/2018/000129 by the Dept. of Science and Technology, Govt. of India. Harish Kumar and Chetan Singh acknowledge the support of FIST Grant Ref No. SR/FST/MS-1/2019/45 by the Dept. of Science and Technology, Govt. of India.

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Appendices

Entropy Scaled Right Eigenvectors for Conservative Part of the Reformulated CGL System

In this section, we present expressions for the right eigenvectors and scaled right eigenvectors for the conservative system

$$\begin{aligned} \frac{\partial {{\textbf {U}}}}{\partial t} + {\mathcal {A}}_x({{\textbf {U}}})\frac{\partial {{\textbf {U}}}}{\partial x} = 0,~~~~~~~~\text {where,}~ {\mathcal {A}}_x({{\textbf {U}}})=\frac{\partial {{\textbf {f}}}_x}{\partial {{\textbf {U}}}} + \phi '({{\textbf {V}}})^\top B_x'({{\textbf {U}}}) \end{aligned}$$
(60)

The right eigenvectors are described in Section A.1, while the expressions of scaled eigenvectors have been demonstrated in Section A.2. We will do all the analysis in the term of primitive variable \({{\textbf {W}}} = \{\rho ,u_x,u_y,u_z,p_\parallel ,p_{\perp },B_x,B_y,B_z\}\).

1.1 Eigenvalues and Right Eigenvectors

To derive the eigenvalues and right eigenvectors, it is useful to transform the system (60) in terms of the primitive variables \({{\textbf {W}}}\). The set of eigenvalues \(\Lambda _1\) of the jacobian matrix \({\mathcal {A}}_x\) are given as

$$\begin{aligned}&\lambda _{1,2,3,4,5,6,7,8}=u_x,~ u_x, ~u_x\pm v_{ax},~u_x\pm c_f,~u_x\pm c_s, \end{aligned}$$

where,

$$\begin{aligned}&v^2_{ax}= \frac{B_x^2}{\rho },~v^2_a=\frac{B^2}{\rho }, ~a^2=\frac{2P_\perp }{\rho },&\\ &c^2_{f,s}=\frac{1}{2}\bigg [(v_a^2+a^2)\pm \sqrt{(v_a^2+a^2)^2-4v^2_{ax}a^2}\bigg ]. \end{aligned}$$

The corresponding right eigenvectors are

$$\begin{aligned}R_{\lambda _1}= & \begin{pmatrix} 1\\ 0\\ 0\\ 0\\ 0\\ 0\\ 0\\ 0\\ \end{pmatrix},R_{\lambda _2}= \begin{pmatrix} 0\\ 0\\ 0\\ 0\\ 1\\ 0\\ 0\\ 0 \end{pmatrix},R_{\lambda _{3,4}}= \begin{pmatrix} 0\\ 0\\ \pm {\beta _z}\\ \mp {\beta _y}\\ 0\\ 0\\ -{\beta _z}sgn(B_x)\sqrt{\rho }\\ {\beta _y}sgn(B_x)\sqrt{\rho }\\ \end{pmatrix},\\ R_{\lambda _{5,6}}= & \begin{pmatrix} \alpha _f \rho \\ \pm \alpha _f c_f\\ \mp \alpha _s c_s \beta _y sgn(B_x)\\ \mp \alpha _s c_s \beta _z sgn(B_x)\\ \alpha _f p_\parallel \\ \alpha _f \rho a^2\\ \alpha _s a\beta _y\sqrt{\rho }\\ \alpha _s a\beta _z\sqrt{\rho } \end{pmatrix},R_{\lambda _{7,8}}= \begin{pmatrix} \alpha _s \rho \\ \pm \alpha _s c_s\\ \pm \alpha _f c_f \beta _y sgn(B_x)\\ \pm \alpha _fc_f \beta _z sgn(B_x)\\ \alpha _s p_\parallel \\ \alpha _s \rho a^2\\ -\alpha _f a\beta _y\sqrt{\rho } \\ -\alpha _f a\beta _z\sqrt{\rho } \end{pmatrix}, \end{aligned}$$

where,

$$\begin{aligned} \alpha _f^2=\frac{a^2-c_s^2}{c_f^2-c_s^2},~\alpha _s^2=\frac{c_f^2-a^2}{c_f^2-c_s^2},~ \beta _y=\frac{B_y}{\sqrt{B_y^2+B_z^2}},~\beta _z=\frac{B_z}{\sqrt{B_y^2+B_z^2}}. \end{aligned}$$

Above all, eigenvectors are linearly independent. The above-defined right eigenvectors are singular in a variety of cases as listed by Balsara and Roe in [3]. Similarly, in y-direction, the set of eigenvalues \(\Lambda _2\) of the jacobian matrix \(\frac{\partial {{\textbf {f}}}_{y}}{\partial {{\textbf {U}}}}\) are given as

$$\begin{aligned}&\lambda _{1,2,3,4,5,6,7,8}=u_y,~ u_y, ~u_y\pm v_{ay},~u_y\pm c_f,~u_x\pm c_s, \end{aligned}$$

where,

$$\begin{aligned}&v^2_{ay}= \frac{B_y^2}{\rho },~v^2_a=\frac{B^2}{\rho }, ~a^2=\frac{2P_\perp }{\rho },&\\ &c^2_{f,s}=\frac{1}{2}\bigg [(v_a^2+a^2)\pm \sqrt{(v_a^2+a^2)^2-4v^2_{ay}a^2}\bigg ]. \end{aligned}$$

the corresponding right eigenvectors are

$$\begin{aligned}R_{\lambda _1}= & \begin{pmatrix} 1\\ 0\\ 0\\ 0\\ 0\\ 0\\ 0\\ 0\\ \end{pmatrix},R_{\lambda _2}= \begin{pmatrix} 0\\ 0\\ 0\\ 0\\ 1\\ 0\\ 0\\ 0 \end{pmatrix},R_{\lambda _{3,4}}= \begin{pmatrix} 0\\ \pm {\beta _z}\\ 0\\ \mp {\beta _x}\\ 0\\ 0\\ -{\beta _z}sgn(B_y)\sqrt{\rho }\\ {\beta _x}sgn(B_y)\sqrt{\rho }\\ \end{pmatrix},\\ R_{\lambda _{5,6}}= & \begin{pmatrix} \alpha _f \rho \\ \mp \alpha _s c_s \beta _x sgn(B_y)\\ \pm \alpha _f c_f\\ \mp \alpha _s c_s \beta _z sgn(B_y)\\ \alpha _f p_\parallel \\ \alpha _f \rho a^2\\ \alpha _s a\beta _x\sqrt{\rho }\\ \alpha _s a\beta _z\sqrt{\rho } \end{pmatrix},R_{\lambda _{7,8}}= \begin{pmatrix} \alpha _s \rho \\ \pm \alpha _f c_f \beta _x sgn(B_y)\\ \pm \alpha _s c_s\\ \pm \alpha _fc_f \beta _z sgn(B_y)\\ \alpha _s p_\parallel \\ \alpha _s \rho a^2\\ -\alpha _f a\beta _x\sqrt{\rho } \\ -\alpha _f a\beta _z\sqrt{\rho } \end{pmatrix}, \end{aligned}$$

where,

$$\begin{aligned} \alpha _f^2=\frac{a^2-c_s^2}{c_f^2-c_s^2},~\alpha _s^2=\frac{c_f^2-a^2}{c_f^2-c_s^2},~ \beta _x=\frac{B_x}{\sqrt{B_x^2+B_z^2}},~\beta _z=\frac{B_z}{\sqrt{B_x^2+B_z^2}}. \end{aligned}$$

1.2 Entropy Scaled Right Eigenvectors

In this section, we have calculated the entropy scaled right eigenvectors for the case of x-direction. Consider the conservative part of the CGL system (60). The eigenvalues and Right eigenvectors in terms of primitive of the Jacobian matrix \({\mathcal {A}}_1\) are described in (A.1). The right eigenvector matrix \(R^x\) for the matrix \({\mathcal {A}}_1\) in terms of conservative variable is given by the relation

$$\begin{aligned} R^x = \frac{\partial {{\textbf {U}}}}{\partial {{\textbf {W}}}} R_{{{\textbf {W}}}}^{x} \end{aligned}$$

where, \(\frac{\partial {{\textbf {U}}}}{\partial {{\textbf {W}}}}\) is the Jacobian matrix for the change of variable, given by

$$\begin{aligned} \frac{\partial {{\textbf {U}}}}{\partial {{\textbf {W}}}}= \begin{pmatrix} 1 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0\\ u_x & \rho & 0 & 0 & 0 & 0 & 0 & 0 & 0\\ u_y & 0 & \rho & 0 & 0 & 0 & 0 & 0 & 0\\ u_z & 0 & 0 & \rho & 0 & 0 & 0 & 0 & 0\\ 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0\\ \frac{{{\textbf {u}}}^2}{2} & \rho u_x & \rho u_y & \rho u_z & \frac{1}{2} & 1 & B_x & B_y & B_z\\ 0 & 0 & 0 & 0 & 0 & 0 & 1 & 0 & 0\\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & 1 & 0\\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 1 \end{pmatrix}. \end{aligned}$$

and the matrix \(R_{{{\textbf {W}}}}^{x}\) is given by,

$$\begin{aligned} \begin{pmatrix} \alpha _f \rho & \alpha _s \rho & 0 & 1 & 0 & 0 & 0 & \alpha _s \rho & \alpha _f \rho \\ -\alpha _f c_f & -\alpha _s c_s & 0 & 0 & 0 & 0 & 0 & \alpha _s c_s & \alpha _f c_f \\ \alpha _s \beta _y c_s {\mathcal {S}}_{x} & -\alpha _f \beta _y c_f {\mathcal {S}}_{x} & -\beta _z & 0 & 0 & 0 & \beta _z & \alpha _f \beta _y c_f {\mathcal {S}}_{x}& -\alpha _s\beta _y c_s {\mathcal {S}}_{x}\\ \alpha _s \beta _z c_s {\mathcal {S}}_{x} & -\alpha _f \beta _z c_f {\mathcal {S}}_{x} & \beta _y & 0 & 0 & 0 & -\beta _y & \alpha _f \beta _z c_f {\mathcal {S}}_{x}& -\alpha _s \beta _z c_s {\mathcal {S}}_{x} \\ \alpha _f p_\parallel & \alpha _s p_\parallel & 0 & 0 & 0 & 1 & 0 & \alpha _s p_\parallel & \alpha _f p_\parallel \\ a^2 \alpha _f \rho & a^2 \alpha _s \rho & 0 & 0 & 0 & 0 & 0 & a^2 \alpha _s \rho & a^2 \alpha _f \rho \\ 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 \\ a \alpha _s \beta _y \sqrt{\rho } & -a \alpha _f \beta _y \sqrt{\rho } & -\beta _z \sqrt{\rho } {\mathcal {S}}_{x} & 0 & 0 & 0 & -\beta _z \sqrt{\rho } {\mathcal {S}}_{x} & -a \alpha _f \beta _y \sqrt{\rho } & a \alpha _s \beta _y \sqrt{\rho } \\ a \alpha _s \beta _z \sqrt{\rho } & -a \alpha _f \beta _z \sqrt{\rho } & \beta _y \sqrt{\rho } {\mathcal {S}}_{x} & 0 & 0 & 0 & \beta _y \sqrt{\rho } {\mathcal {S}}_{x} & -a \alpha _f \beta _z \sqrt{\rho } & a \alpha _s \beta _z \sqrt{\rho } \\ \end{pmatrix}. \end{aligned}$$

where, \({\mathcal {S}}_{x} = sgn(B_x)\). We need to find a scaling matrix \(T^x\) such that the scaled right eigenvector matrix \(\tilde{R}^x=R^x T^x\) satisfies

$$\begin{aligned} \frac{\partial {{\textbf {U}}}}{\partial {{\textbf {V}}}} = \tilde{R}^x \tilde{R}^{x\top } \end{aligned}$$
(61)

where \({{\textbf {V}}}\) is the entropy variable vector as in Eqn. (12). We follow the Barth scaling process [6] to scale the right eigenvectors. The scaling matrix \(T^x\) is the square root of \(Y^x\), where \(Y^x\) has the expression

$$\begin{aligned} Y^x = (R_{{{\textbf {W}}}}^{x})^{-1} \frac{\partial {{\textbf {W}}}}{\partial {{\textbf {V}}}}\left( \frac{\partial {{\textbf {U}}}}{\partial {{\textbf {W}}}}\right) ^{-\top }(R_{{{\textbf {W}}}}^{x}) ^{-\top } \end{aligned}$$

which results in

$$\begin{aligned} Y^x = \begin{pmatrix} \frac{1}{8\rho } & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0\\ 0 & \frac{1}{8\rho } & 0 & 0 & 0 & 0 & 0 & 0 & 0\\ 0 & 0 & \frac{p_{\perp }}{4\rho ^2} & 0 & 0 & 0 & 0 & 0 & 0\\ 0 & 0 & 0 & \frac{\rho }{4} & 0 & \frac{p_\parallel }{4} & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & \frac{p_{\perp }}{2\rho } & 0 & 0 & 0 & 0\\ 0 & 0 & 0 & \frac{p_\parallel }{4} & 0& \frac{5 p_\parallel ^2}{4\rho } & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & 0 & 0 & \frac{p_{\perp }}{4\rho ^2}& 0 & 0\\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & \frac{1}{8\rho } & 0\\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & \frac{1}{8\rho } \end{pmatrix}. \end{aligned}$$

Then matrix \(T^x\) is,

$$\begin{aligned} \begin{pmatrix} \frac{1}{2\sqrt{2\rho }} & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0\\ 0 & \frac{1}{2\sqrt{2\rho }} & 0 & 0 & 0 & 0 & 0 & 0 & 0\\ 0 & 0 & \frac{\sqrt{p_{\perp }}}{2\rho } & 0 & 0 & 0 & 0 & 0 & 0\\ 0 & 0 & 0 & \frac{\sqrt{\rho }(2 p_\parallel + \rho )}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}} & 0 & \frac{p_\parallel \sqrt{\rho }}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}} & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & \sqrt{\frac{p_{\perp }}{2\rho }} & 0 & 0 & 0 & 0\\ 0 & 0 & 0 & \frac{p_\parallel \sqrt{\rho }}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}} & 0 & \frac{p_\parallel (5 p_\parallel + 2 \rho )}{2 \sqrt{\rho (5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2)}}& 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & 0 & 0 & \frac{\sqrt{p_{\perp }}}{2\rho }& 0 & 0\\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & \frac{1}{2\sqrt{2\rho }} & 0\\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & \frac{1}{2\sqrt{2\rho }} \end{pmatrix}. \end{aligned}$$

Remark 3

For finding the square root of \(3\times 3\) matrix

$$\begin{aligned} M = \begin{pmatrix} a & 0 & b\\ 0 & e & 0 \\ c & 0 & d \end{pmatrix} \end{aligned}$$

where a , b , c, d and e are real or complex numbers. we apply the formula,

$$\begin{aligned} R = \begin{pmatrix} \frac{a+s}{t} & 0 & \frac{b}{t}\\ 0 & \sqrt{e} & 0\\ \frac{c}{t} & 0 & \frac{d+s}{t} \end{pmatrix}. \end{aligned}$$

where, \(\delta = ad-bc\), \(\tau = a+d\) and \(s=\sqrt{\delta }\), \(t=\sqrt{\tau +2s}\). We apply this formula if \(t \ne 0\).

Remark 4

We proceed similarly in the y-direction, the eigenvalues and Right eigenvectors in terms of primitive of the Jacobian matrix \(\frac{\partial {{\textbf {f}}}_{2}}{\partial {{\textbf {U}}}}\) describe in (A.1). The right eigenvector matrix is given by the relation

$$\begin{aligned} R^y = \frac{\partial {{\textbf {U}}}}{\partial {{\textbf {W}}}} R_{{{\textbf {W}}}}^{y} \end{aligned}$$

where, \(R_{{{\textbf {W}}}}^{y}\) is given below

$$\begin{aligned} \begin{pmatrix} \alpha _f \rho & \alpha _s \rho & 0 & 1 & 0 & 0 & 0 & \alpha _s \rho & \alpha _f \rho \\ \alpha _s \beta _x c_s {\mathcal {S}}_{y} & -\alpha _f \beta _x c_f {\mathcal {S}}_{y} & -\beta _z & 0 & 0 & 0 & \beta _z & \alpha _f \beta _x c_f {\mathcal {S}}_{y}& -\alpha _s\beta _x c_s {\mathcal {S}}_{y}\\ -\alpha _f c_f & -\alpha _s c_s & 0 & 0 & 0 & 0 & 0 & \alpha _s c_s & \alpha _f c_f \\ \alpha _s \beta _z c_s {\mathcal {S}}_{y} & -\alpha _f \beta _z c_f {\mathcal {S}}_{y} & \beta _x & 0 & 0 & 0 & -\beta _x & \alpha _f \beta _z c_f {\mathcal {S}}_{y}& -\alpha _s \beta _z c_s {\mathcal {S}}_{y}\\ \alpha _f p_\parallel & \alpha _s p_\parallel & 0 & 0 & 0 & 1 & 0 & \alpha _s p_\parallel & \alpha _f p_\parallel \\ a^2 \alpha _f \rho & a^2 \alpha _s \rho & 0 & 0 & 0 & 0 & 0 & a^2 \alpha _s \rho & a^2 \alpha _f \rho \\ a \alpha _s \beta _x \sqrt{\rho } & -a \alpha _f \beta _x \sqrt{\rho } & -\beta _z \sqrt{\rho } {\mathcal {S}}_{y} & 0 & 0 & 0 & -\beta _z \sqrt{\rho } {\mathcal {S}}_{y} & -a \alpha _f \beta _x \sqrt{\rho } & a \alpha _s \beta _x \sqrt{\rho } \\ 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 \\ a \alpha _s \beta _z \sqrt{\rho } & -a \alpha _f \beta _z \sqrt{\rho } & \beta _x \sqrt{\rho } {\mathcal {S}}_{y} & 0 & 0 & 0 & \beta _x \sqrt{\rho } {\mathcal {S}}_{y} & -a \alpha _f \beta _z \sqrt{\rho } & a \alpha _s \beta _z \sqrt{\rho } \\ \end{pmatrix} \end{aligned}$$

where, \({\mathcal {S}}_{y} = sgn(B_y)\). Accordingly, we obtain the scaling matrix \(T^y\) as,

$$\begin{aligned} \begin{pmatrix} \frac{1}{2\sqrt{2\rho }} & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0\\ 0 & \frac{1}{2\sqrt{2\rho }} & 0 & 0 & 0 & 0 & 0 & 0 & 0\\ 0 & 0 & \frac{\sqrt{p_{\perp }}}{2\rho } & 0 & 0 & 0 & 0 & 0 & 0\\ 0 & 0 & 0 & \frac{\sqrt{\rho }(2 p_\parallel + \rho )}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}} & 0 & \frac{p_\parallel \sqrt{\rho }}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}} & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & \sqrt{\frac{p_{\perp }}{2\rho }} & 0 & 0 & 0 & 0\\ 0 & 0 & 0 & \frac{p_\parallel \sqrt{\rho }}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}} & 0 & \frac{p_\parallel (5 p_\parallel + 2 \rho )}{2 \sqrt{\rho (5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2)}}& 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & 0 & 0 & \frac{\sqrt{p_{\perp }}}{2\rho }& 0 & 0\\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & \frac{1}{2\sqrt{2\rho }} & 0\\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & \frac{1}{2\sqrt{2\rho }} \end{pmatrix}. \end{aligned}$$

1.3 Entropy Scaled Right Eigenvectors in x and y Direction

In x direction, the entropy-scaled right eigenvectors corresponding to the above eigenvalues in the term of primitive variables are the following,

$$\begin{aligned}{\tilde{R}}_{\lambda _1}= & \begin{pmatrix} \frac{\sqrt{\rho }(2 p_\parallel + \rho )}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}}\\ 0\\ 0\\ 0\\ \frac{p_\parallel \sqrt{\rho }}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}}\\ 0\\ 0\\ 0\\ 0 \end{pmatrix},{\tilde{R}}_{\lambda _2}= \begin{pmatrix} 0\\ 0\\ 0\\ 0\\ 0\\ 0\\ \sqrt{\frac{p_{\perp }}{2 \rho }}\\ 0\\ 0 \end{pmatrix},{\tilde{R}}_{\lambda _3}= \begin{pmatrix} \frac{p_\parallel \sqrt{\rho }}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}}\\ 0\\ 0\\ 0\\ \frac{p_\parallel (5 p_\parallel + 2 \rho )}{2 \sqrt{\rho (5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2)}}\\ 0\\ 0\\ 0\\ 0 \end{pmatrix},\\ {\tilde{R}}_{\lambda _{4,5}}= & \frac{1}{2}\begin{pmatrix} 0\\ 0\\ \pm \frac{\sqrt{p_{\perp }}}{\rho }{\beta _z}\\ \mp \frac{\sqrt{p_{\perp }}}{\rho }{\beta _y}\\ 0\\ 0\\ 0\\ -\sqrt{\frac{p_{\perp }}{\rho }}{\beta _z}\\ \sqrt{\frac{p_{\perp }}{\rho }}{\beta _y}\\ \end{pmatrix},{\tilde{R}}_{\lambda _{6,7}}= \frac{1}{2\sqrt{2}}\begin{pmatrix} \alpha _f \sqrt{\rho }\\ \pm \frac{\alpha _f c_f}{\sqrt{\rho }}\\ \mp \frac{\alpha _s c_s \beta _y}{\sqrt{\rho }}\\ \mp \frac{\alpha _s c_s \beta _z}{\sqrt{\rho }}\\ \alpha _f \frac{p_\parallel }{\sqrt{\rho }}\\ \alpha _f \sqrt{\rho } a^2\\ 0\\ \alpha _s a\beta _y\\ \alpha _s a\beta _z \end{pmatrix},{\tilde{R}}_{\lambda _{8,9}}= \frac{1}{2\sqrt{2}}\begin{pmatrix} \alpha _s \sqrt{\rho }\\ \pm \frac{\alpha _s c_s}{\sqrt{\rho }}\\ \pm \frac{\alpha _f c_f \beta _y}{\sqrt{\rho }}\\ \pm \frac{\alpha _f c_f \beta _z}{\sqrt{\rho }}\\ \alpha _s \frac{p_\parallel }{\sqrt{\rho }}\\ \alpha _s \sqrt{\rho } a^2\\ 0\\ -\alpha _f a\beta _y\\ -\alpha _f a\beta _z \end{pmatrix}, \end{aligned}$$

In y-direction, the entropy-scaled right eigenvectors corresponding to the above eigenvalues in the term of primitive variables are the following,

$$\begin{aligned}{\tilde{R}}_{\lambda _1}= & \begin{pmatrix} \frac{\sqrt{\rho }(2 p_\parallel + \rho )}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}}\\ 0\\ 0\\ 0\\ \frac{p_\parallel \sqrt{\rho }}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}}\\ 0\\ 0\\ 0\\ 0 \end{pmatrix},{\tilde{R}}_{\lambda _2}= \begin{pmatrix} 0\\ 0\\ 0\\ 0\\ 0\\ 0\\ 0\\ \sqrt{\frac{p_{\perp }}{2 \rho }}\\ 0 \end{pmatrix},{\tilde{R}}_{\lambda _3}= \begin{pmatrix} \frac{p_\parallel \sqrt{\rho }}{2 \sqrt{5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2}}\\ 0\\ 0\\ 0\\ \frac{p_\parallel (5 p_\parallel + 2 \rho )}{2 \sqrt{\rho (5 p_\parallel ^{2} + 4 p_\parallel \rho + \rho ^2)}}\\ 0\\ 0\\ 0\\ 0 \end{pmatrix},\\ {\tilde{R}}_{\lambda _{4,5}}= & \frac{1}{2}\begin{pmatrix} 0\\ \pm \frac{\sqrt{p_{\perp }}}{\rho }{\beta _z}\\ 0\\ \mp \frac{\sqrt{p_{\perp }}}{\rho }{\beta _x}\\ 0\\ 0\\ -\sqrt{\frac{p_{\perp }}{\rho }}{\beta _z}\\ 0\\ \sqrt{\frac{p_{\perp }}{\rho }}{\beta _x}\\ \end{pmatrix},{\tilde{R}}_{\lambda _{6,7}}= \frac{1}{2\sqrt{2}}\begin{pmatrix} \alpha _f \sqrt{\rho }\\ \mp \frac{\alpha _s c_s \beta _x}{\sqrt{\rho }}\\ \pm \frac{\alpha _f c_f}{\sqrt{\rho }}\\ \mp \frac{\alpha _s c_s \beta _z}{\sqrt{\rho }}\\ \alpha _f \frac{p_\parallel }{\sqrt{\rho }}\\ \alpha _f \sqrt{\rho } a^2\\ \alpha _s a\beta _x\\ 0\\ \alpha _s a\beta _z \end{pmatrix},{\tilde{R}}_{\lambda _{8,9}}= \frac{1}{2\sqrt{2}}\begin{pmatrix} \alpha _s \sqrt{\rho }\\ \pm \frac{\alpha _f c_f \beta _x}{\sqrt{\rho }}\\ \pm \frac{\alpha _s c_s}{\sqrt{\rho }}\\ \pm \frac{\alpha _f c_f \beta _z}{\sqrt{\rho }}\\ \alpha _s \frac{p_\parallel }{\sqrt{\rho }}\\ \alpha _s \sqrt{\rho } a^2\\ -\alpha _f a\beta _x\\ 0\\ -\alpha _f a\beta _z \end{pmatrix}, \end{aligned}$$

Proof of \({{\textbf {V}}}^\top \cdot {{\textbf {C}}}_x({{\textbf {U}}}) = {{\textbf {V}}}^\top \cdot {{\textbf {C}}}_y({{\textbf {U}}}) = 0\)

The entropy variable \({{\textbf {V}}}:=\frac{\partial {\mathcal {E}}}{\partial {{\textbf {U}}}}\) is given by

$$\begin{aligned} {{\textbf {V}}}&=\Bigg \{5-s-\beta _\perp {{\textbf {u}}}^2,~2\beta _\perp {{\textbf {u}}},~-\beta _\parallel +\beta _\perp ,~-2\beta _\perp ,~2\beta _\perp \varvec{B}\Bigg \}^\top \end{aligned}$$

where \(\beta _\perp =\frac{\rho }{p_{\perp }},\) and \(\beta _\parallel =\frac{\rho }{p_\parallel }\). Now the dot product of \({{\textbf {V}}}^\top \) and first coloum of \({{\textbf {C}}}_x({{\textbf {U}}})\) is:

$$\begin{aligned}&{{\textbf {V}}}^\top \cdot \left\{ 0,-\frac{b_x^2 {{\textbf {u}}}^2}{2},-\frac{b_xb_y {{\textbf {u}}}^2}{2},-\frac{b_xb_z {{\textbf {u}}}^2}{2},-\frac{2p_\parallel b_x}{\rho }({\varvec{b}}\cdot {{\textbf {u}}}), \Upsilon _1^x,0,0,0\right\} =\\&\quad = \left( 2\frac{\rho }{p_{\perp }} u_x\right) \left( -\frac{b_x^2 {{\textbf {u}}}^2}{2}\right) +\left( 2\frac{\rho }{p_{\perp }} u_y\right) \left( -\frac{b_xb_y {{\textbf {u}}}^2}{2}\right) +\left( 2\frac{\rho }{p_{\perp }}u_z\right) \left( -\frac{b_xb_z {{\textbf {u}}}^2}{2}\right) \\&\qquad +\left( \frac{\rho (p_\parallel -p_{\perp })}{p_\parallel p_{\perp }}\right) \left( -\frac{2p_\parallel b_x}{\rho }({\varvec{b}}\cdot {{\textbf {u}}})\right) +\left( -2\frac{\rho }{p_{\perp }}\right) (\Upsilon _1^x)\\&\quad =\left( 2\frac{\rho }{p_{\perp }} u_x\right) \left( -\frac{b_x^2 {{\textbf {u}}}^2}{2}\right) +\left( 2\frac{\rho }{p_{\perp }} u_y\right) \left( -\frac{b_xb_y {{\textbf {u}}}^2}{2}\right) +\left( 2\frac{\rho }{p_{\perp }}u_z\right) \left( -\frac{b_xb_z {{\textbf {u}}}^2}{2}\right) \\&\qquad +\left( \frac{\rho (p_\parallel -p_{\perp })}{p_\parallel p_{\perp }}\right) \left( -\frac{2p_\parallel b_x}{\rho }({\varvec{b}}\cdot {{\textbf {u}}})\right) \\&\qquad +\left( -2\frac{\rho }{p_{\perp }}\right) \left( -b_x(b\cdot {{\textbf {u}}})\frac{{{\textbf {u}}}^2}{2}-\frac{(p_\parallel - p_{\perp })b_x({\varvec{b}}\cdot {{\textbf {u}}})}{\rho }\right) \\&\quad =0 \end{aligned}$$

Now the dot product of \({{\textbf {V}}}^\top \) and second coloum of \({{\textbf {C}}}_x({{\textbf {U}}})\) is:

$$\begin{aligned}&{{\textbf {V}}}^\top \cdot \left\{ 0,b_x^2 u_x,b_xb_y u_x,b_xb_z u_x,\frac{2p_\parallel b_x}{\rho }b_x,\Upsilon _2^x,0,0,0\right\} =\\&\quad =\left( 2\frac{\rho }{p_{\perp }} u_x\right) (b_x^2 u_x) + \left( 2\frac{\rho }{p_{\perp }} u_y\right) (b_xb_y u_x) +\left( 2\frac{\rho }{p_{\perp }}u_z\right) (b_xb_z u_x) \\&\qquad + \left( \frac{\rho (p_\parallel -p_{\perp })}{p_\parallel p_{\perp }}\right) \left( \frac{2p_\parallel b_x}{\rho }b_x\right) +\left( -2\frac{\rho }{p_{\perp }}\right) \left( b_x({\varvec{b}}\cdot {{\textbf {u}}})u_x+\frac{(p_\parallel -p_{\perp })b^2_x}{\rho }\right) \\&\quad =0 \end{aligned}$$

Now the dot product of \({{\textbf {V}}}^\top \) and third coloum of \({{\textbf {C}}}_x({{\textbf {U}}})\) is:

$$\begin{aligned}&{{\textbf {V}}}^\top \cdot \left\{ 0,b_x^2 u_y,b_xb_y u_y,b_xb_z u_y,\frac{2p_\parallel b_x}{\rho }b_y,\Upsilon _3^x,0,0,0\right\} =\\&\quad =\left( 2\frac{\rho }{p_{\perp }} u_x\right) (b_x^2 u_y) + \left( 2\frac{\rho }{p_{\perp }} u_y\right) (b_xb_y u_y) +\left( 2\frac{\rho }{p_{\perp }}u_z\right) (b_xb_z u_y) \\&\qquad + \left( \frac{\rho (p_\parallel -p_{\perp })}{p_\parallel p_{\perp }}\right) \left( \frac{2p_\parallel b_x}{\rho }b_y\right) + \left( -2\frac{\rho }{p_{\perp }}\right) \left( b_x({\varvec{b}}\cdot {{\textbf {u}}})u_y+\frac{(p_\parallel - p_{\perp })b_xb_y}{\rho }\right) \\&\quad =0 \end{aligned}$$

Now the dot product of \({{\textbf {V}}}^\top \) and fourth coloum of \({{\textbf {C}}}_x({{\textbf {U}}})\) is:

$$\begin{aligned}&{{\textbf {V}}}^\top \cdot \left\{ 0,b_x^2 u_z,b_xb_y u_z,b_xb_z u_z,\frac{2p_\parallel b_x}{\rho }b_z,\Upsilon _4^x,0,0,0\right\} =\\&\quad =\left( 2\frac{\rho }{p_{\perp }} u_x\right) (b_x^2 u_z) + \left( 2\frac{\rho }{p_{\perp }} u_y\right) (b_xb_y u_z) +\left( 2\frac{\rho }{p_{\perp }}u_z\right) (b_xb_z u_z) \\&\qquad + \left( \frac{\rho (p_\parallel -p_{\perp })}{p_\parallel p_{\perp }}\right) \left( \frac{2p_\parallel b_x}{\rho }b_z\right) + \left( -2\frac{\rho }{p_{\perp }}\right) \left( b_x({\varvec{b}}\cdot {{\textbf {u}}})u_z+\frac{(p_\parallel - p_{\perp })b_xb_z}{\rho }\right) \\&\quad =0 \end{aligned}$$

Now the dot product of \({{\textbf {V}}}^\top \) and fifth coloum of \({{\textbf {C}}}_x({{\textbf {U}}})\) is:

$$\begin{aligned}&{{\textbf {V}}}^\top \cdot \left\{ 0, \frac{3}{2}b_x^2, \frac{3}{2}b_xb_y, \frac{3}{2}b_xb_z ,0, \frac{3}{2}b_x(b\cdot {{\textbf {u}}}),0,0,0\right\} =\\&\quad =\left( 2\frac{\rho }{p_{\perp }} u_x\right) \left( \frac{3}{2}b_x^2\right) + \left( 2\frac{\rho }{p_{\perp }} u_y\right) \left( \frac{3}{2}b_xb_y\right) +\left( 2\frac{\rho }{p_{\perp }}u_z\right) \left( \frac{3}{2}b_xb_z\right) \\&\qquad + \left( -2\frac{\rho }{p_{\perp }}\right) \left( \frac{3}{2}b_x({\varvec{b}}\cdot {{\textbf {u}}})\right) \\&\quad =0 \end{aligned}$$

Now the dot product of \({{\textbf {V}}}^\top \) and sixth coloum of \({{\textbf {C}}}_x({{\textbf {U}}})\) is:

$$\begin{aligned}&{{\textbf {V}}}^\top \cdot \left\{ 0, -b_x^2, -b_xb_y, -b_xb_z ,0, -b_x(b\cdot {{\textbf {u}}}),0,0,0\right\} =\\&\quad =\left( 2\frac{\rho }{p_{\perp }} u_x\right) (-b_x^2) + \left( 2\frac{\rho }{p_{\perp }} u_y\right) (-b_xb_y) +\left( 2\frac{\rho }{p_{\perp }}u_z\right) (-b_xb_z)\\&\qquad + \left( -2\frac{\rho }{p_{\perp }}\right) \left( -b_x({\varvec{b}}\cdot {{\textbf {u}}})\right) \\&\quad =0 \end{aligned}$$

The seventh coloum, 8th coloum and ninth coloum of \({{\textbf {C}}}_x({{\textbf {U}}})\) denoted by \(C_7,~C_8\) and \(C_9\) is given below,

$$\begin{aligned}C_7= & \begin{pmatrix} 0 \\ b_x^2 B_x+\frac{2\Gamma _xb_x}{|\varvec{B}|} \\ b_xb_y B_x+\frac{\Gamma _xb_y - \Delta Pb_{yxx}}{|\varvec{B}|} \\ b_xb_z B_x+\frac{\Gamma _xb_z - \Delta Pb{zxx}}{|\varvec{B}|} \\ 0 \\ b_x({\varvec{b}}\cdot {{\textbf {u}}})B_x + \Theta ^x_1 \\ 0 \\ 0 \\ 0 \end{pmatrix},C_8= \begin{pmatrix} 0 \\ b_x^2 B_y - \frac{2\Delta Pb_{yxx}}{|\varvec{B}|} \\ b_x b_y B_y+\frac{\Gamma _y b_x - \Delta Pb_{xyy}}{|\varvec{B}|} \\ b_xb_z B_y-\frac{2\Delta Pb_{xyz}}{|\varvec{B}|} \\ 0 \\ b_x({\varvec{b}}\cdot {{\textbf {u}}})B_y + \Theta ^x_2 \\ 0 \\ 0 \\ 0 \end{pmatrix},\\ C_9= & \begin{pmatrix} 0 \\ b_x^2 B_z-\frac{2\Delta Pb_{zxx}}{|\varvec{B}|} \\ b_xb_y B_z-\frac{2\Delta Pb_{xyz}}{|\varvec{B}|} \\ b_xb_z B_z + \frac{\Gamma _zb_x - \Delta Pb_{xzz}}{|\varvec{B}|} \\ 0 \\ b_x({\varvec{b}}\cdot {{\textbf {u}}})B_z + \Theta ^x_3 \\ 0 \\ 0 \\ 0 \end{pmatrix}. \end{aligned}$$

Now the dot product of \({{\textbf {V}}}^\top \) and seventh coloum of \({{\textbf {C}}}_x({{\textbf {U}}})\) is:

$$\begin{aligned} {{\textbf {V}}}^\top \cdot C_7&= \left( 2\frac{\rho }{p_{\perp }} u_x\right) \left( b_x^2 B_x+\frac{2(p_\parallel - p_{\perp })b_x(1-b_x^2)}{|\varvec{B}|}\right) \\&\quad + \left( 2\frac{\rho }{p_{\perp }} u_y\right) \left( b_xb_y B_x+\frac{(p_\parallel - p_{\perp })b_y(1-b_x^2)}{|\varvec{B}|}- \frac{(p_\parallel - p_{\perp })b_yb_x^2}{|\varvec{B}|}\right) \\&\quad +\left( 2\frac{\rho }{p_{\perp }}u_z\right) \left( b_xb_z B_x+\frac{(p_\parallel - p_{\perp })b_z(1-b_x^2)}{|\varvec{B}|} - \frac{(p_\parallel - p_{\perp })b_zb_x^2}{|\varvec{B}|}\right) \\&\quad +\left( -2\frac{\rho }{p_{\perp }}\right) \Bigg (b_x({\varvec{b}}\cdot {{\textbf {u}}})B_x + \left\{ (p_\parallel - p_{\perp })({\varvec{b}}\cdot {{\textbf {u}}})+(p_\parallel - p_{\perp })b_x u_x\right\} \Bigg (\frac{1-b^2_x}{|\varvec{B}|}\Bigg )\\&\quad -(p_\parallel - p_{\perp })\frac{b^2_x b_y u_y}{|\varvec{B}|}- (p_\parallel - p_{\perp })\frac{b^2_x b_z u_z}{|\varvec{B}|}\Bigg )\\&=0 \end{aligned}$$

Now the dot product of \({{\textbf {V}}}^\top \) and 8th coloum of \({{\textbf {C}}}_x({{\textbf {U}}})\) is:

$$\begin{aligned} {{\textbf {V}}}^\top \cdot C_8&= \left( 2\frac{\rho }{p_{\perp }} u_x\right) \left( b_x^2 B_y-\frac{2(p_\parallel - p_{\perp })b_yb_x^2}{|\varvec{B}|}\right) \\&\quad + \left( 2\frac{\rho }{p_{\perp }} u_y\right) \left( b_xb_y B_y+\frac{(p_\parallel - p_{\perp })b_x(1-b_y^2)}{|\varvec{B}|} - \frac{(p_\parallel - p_{\perp })b_xb_y^2}{|\varvec{B}|}\right) \\&\quad +\left( 2\frac{\rho }{p_{\perp }}u_z\right) \left( b_xb_z B_y-\frac{2(p_\parallel - p_{\perp })b_xb_yb_z}{|\varvec{B}|}\right) \\&\quad +\left( -2\frac{\rho }{p_{\perp }}\right) \Bigg (b_x({\varvec{b}}\cdot {{\textbf {u}}})B_y + (p_\parallel - p_{\perp })b_x u_y \Bigg (\frac{1-b^2_y}{|\varvec{B}|}\Bigg ) - (p_\parallel - p_{\perp })\frac{b_x b_y b_z u_z}{|\varvec{B}|} \\&\quad -\{(p_\parallel - p_{\perp })({\varvec{b}}\cdot {{\textbf {u}}})+(p_\parallel - p_{\perp })b_x u_x\}\frac{b_x b_y}{|\varvec{B}|}\Bigg )\\&=0 \end{aligned}$$

Now the dot product of \({{\textbf {V}}}^\top \) and ninth coloum of \({{\textbf {C}}}_x({{\textbf {U}}})\) is:

$$\begin{aligned} {{\textbf {V}}}^\top \cdot C_9&= \left( 2\frac{\rho }{p_{\perp }} u_x\right) \left( b_x^2 B_z-\frac{2(p_\parallel - p_{\perp })b_zb_x^2}{|\varvec{B}|}\right) \\&\quad + \left( 2\frac{\rho }{p_{\perp }} u_y\right) \left( b_xb_y B_z-\frac{2(p_\parallel - p_{\perp })b_xb_yb_z}{|\varvec{B}|}\right) \\&\quad +\left( 2\frac{\rho }{p_{\perp }}u_z\right) \left( b_xb_z B_z+\frac{(p_\parallel - p_{\perp })b_x(1-b_z^2)}{|\varvec{B}|} - \frac{(p_\parallel - p_{\perp })b_xb_z^2}{|\varvec{B}|}\right) \\&\quad +\left( -2\frac{\rho }{p_{\perp }}\right) \Bigg (b_x({\varvec{b}}\cdot {{\textbf {u}}})B_z + (p_\parallel - p_{\perp })b_x u_z \Bigg (\frac{1-b^2_z}{|\varvec{B}|}\Bigg ) - (p_\parallel - p_{\perp })\frac{b_x b_y b_z u_y}{|\varvec{B}|}\\&\quad -\{(p_\parallel - p_{\perp })({\varvec{b}}\cdot {{\textbf {u}}})+(p_\parallel - p_{\perp })b_x u_x\}\frac{b_x b_z}{|\varvec{B}|}\Bigg )\\&=0 \end{aligned}$$

Similarly we can proof that \({{\textbf {V}}}^\top \cdot {{\textbf {C}}}_y({{\textbf {U}}}) = 0\) for y-direction.

Non-Symmetrizability of CGL System

In this section, we have discussed the symmetrizability of the following CGL equations. Consider CGL equations in one dimension as follows:

$$\begin{aligned} \frac{\partial {{\textbf {U}}}}{\partial t}+\frac{\partial {{\textbf {f}}}_{x}}{\partial x} + {{\textbf {C}}}_{x}({{\textbf {U}}})\frac{\partial {{\textbf {U}}}}{\partial x} =0. \end{aligned}$$
(62)

where \({{\textbf {U}}},~{{\textbf {f}}}_{x}\) and \({{\textbf {C}}}_{x}({{\textbf {U}}})\) are defined in (3). Follow [68], the CGL equations are said to be symmetrizable if the change of variable \({{\textbf {U}}}\rightarrow {{\textbf {V}}}\) applied to (62) and can be written as:

$$\begin{aligned} \frac{\partial {{\textbf {U}}}}{\partial {{\textbf {V}}}}\frac{\partial {{\textbf {V}}}}{\partial {t}}+\left( \frac{\partial {{\textbf {f}}}_x}{\partial {{\textbf {U}}}} +{{\textbf {C}}}_{x}({{\textbf {U}}}) \right) \frac{\partial {{\textbf {U}}}}{\partial {{\textbf {V}}}}\frac{\partial {{\textbf {V}}}}{\partial {x}}=0. \end{aligned}$$

the matrix \(\frac{\partial {{\textbf {U}}}}{\partial {{\textbf {V}}}}\) is a symmetric, positive definite matrix and \(\aleph ({{\textbf {U}}}) = \left( \frac{\partial {{\textbf {f}}}_x}{\partial {{\textbf {U}}}} +{{\textbf {C}}}_{x}({{\textbf {U}}}) \right) \frac{\partial {{\textbf {U}}}}{\partial {{\textbf {V}}}}\) is symmetric matrix. For the CGL equation (62), we calculate matrix \(\aleph ({{\textbf {U}}})\) to examine its symmetry and conclude that CGL equations are non-symmetrizable. The resultant matrix \(\aleph ({{\textbf {U}}}) -\aleph ({{\textbf {U}}})^\top \) is given below:

$$\begin{aligned} \begin{pmatrix} 0 & -\frac{\Delta Pb_x^2}{2} & -\frac{\Delta Pb_x b_y}{2} & -\frac{\Delta Pb_x b_z}{2} & 0 & -\frac{\Delta Pb_x ({\varvec{b}}\cdot {{\textbf {u}}})}{2} & 0 & 0 & 0\\ \frac{\Delta Pb_x^2}{2} & 0 & \frac{\Delta Pb_x (b_x u_y - b_y u_x)}{2} & \frac{\Delta Pb_x (b_x u_z - b_z u_x)}{2} & \frac{3 \Delta Pp_\parallel b_x^2}{2\rho } & -\frac{\alpha _{xyz}}{4\rho } & -\frac{p_{\perp }\omega _1}{2\rho } & -\frac{\Delta Pp_{\perp }b_y b_x^2}{\rho |\varvec{B}|} & -\frac{\Delta Pp_{\perp }b_z b_x^2}{\rho |\varvec{B}|}\\ \frac{\Delta Pb_x b_y}{2} & \frac{\Delta Pb_x (b_y u_x - b_x u_y)}{2} & 0 & \frac{\Delta Pb_x (b_y u_z - b_z u_y)}{2} & \frac{3 \Delta Pp_\parallel b_x b_y}{2\rho } & -\frac{\alpha _{yxz}}{4\rho } & -\frac{p_{\perp }\omega _2}{2\rho } & \frac{\Delta Pp_{\perp }b_x (1-2b_y^2)}{2\rho |\varvec{B}|} & -\frac{\Delta Pp_{\perp }b_x b_y b_z}{\rho |\varvec{B}|}\\ \frac{\Delta Pb_x b_z}{2} & \frac{\Delta Pb_x (b_z u_x - b_x u_z)}{2} & \frac{\Delta Pb_x (b_z u_y - b_y u_z)}{2} & 0 & \frac{3 \Delta Pp_\parallel b_x b_z}{2\rho } & -\frac{\alpha _{zxy}}{4\rho } & -\frac{p_{\perp }\omega _3}{2\rho } & -\frac{\Delta Pp_{\perp }b_x b_y b_z}{\rho |\varvec{B}|} & \frac{\Delta Pp_{\perp }b_x (1-2b_z^2)}{2\rho |\varvec{B}|} \\ 0 & -\frac{3 \Delta Pp_\parallel b_x^2}{2\rho } & -\frac{3 \Delta Pp_\parallel b_x b_y}{2\rho } & -\frac{3 \Delta Pp_\parallel b_x b_z}{2\rho } & 0 & -\frac{3 \Delta Pp_\parallel b_x({\varvec{b}}\cdot {{\textbf {u}}}) }{2\rho } & 0 & 0 & 0 \\ \frac{\Delta Pb_x ({\varvec{b}}\cdot {{\textbf {u}}})}{2} & \frac{\alpha _{xyz}}{4\rho } & \frac{\alpha _{yxz}}{4\rho } & \frac{\alpha _{zxy}}{4\rho } & \frac{3 \Delta Pp_\parallel b_x({\varvec{b}}\cdot {{\textbf {u}}}) }{2\rho } & 0 & -\frac{p_{\perp }\beta _1}{2 \rho } & \frac{p_{\perp }\beta _2}{2 \rho } & \frac{p_{\perp }\beta _3}{2 \rho }\\ 0 & \frac{p_{\perp }\omega _1}{2\rho } & \frac{p_{\perp }\omega _2}{2\rho } & \frac{p_{\perp }\omega _3}{2\rho } & 0 & \frac{p_{\perp }\beta _1}{2 \rho } & 0 & \frac{p_{\perp }u_y}{2\rho } & \frac{p_{\perp }u_z}{2\rho }\\ 0 & \frac{\Delta Pp_{\perp }b_y b_x^2}{\rho |\varvec{B}|} & -\frac{\Delta Pp_{\perp }b_x (1-2b_y^2)}{2\rho |\varvec{B}|} & \frac{\Delta Pp_{\perp }b_x b_y b_z}{\rho |\varvec{B}|} & 0 & -\frac{p_{\perp }\beta _2}{2 \rho } & -\frac{p_{\perp }u_y}{2\rho } & 0 & 0\\ 0 & \frac{\Delta Pp_{\perp }b_z b_x^2}{\rho |\varvec{B}|} & \frac{\Delta Pp_{\perp }b_x b_y b_z}{\rho |\varvec{B}|} & -\frac{\Delta Pp_{\perp }b_x (1-2b_z^2)}{2\rho |\varvec{B}|} & 0 & -\frac{p_{\perp }\beta _3}{2 \rho } & -\frac{p_{\perp }u_z}{2\rho } & 0 & 0 \end{pmatrix}. \end{aligned}$$

where, \(\Delta P= (p_\parallel -p_{\perp })\) and \(\alpha _{lmn}= 2 p_{\perp }B_x B_l + \Delta Pb_x\Big (2 \rho u_l (b_m u_m + b_n u_n) - b_l \) \((3p_\parallel +2p_{\perp }+ \rho (u_m^2 +u_n^2 - u_l^2))\Big );~~\forall ~l,m,n \in \{x,y,z\}\)

\(\beta _1 = B_y u_y + B_z u_z + \frac{\Delta P\left( -b_y u_y - b_z u_z + 2 b_x(({\varvec{b}}\cdot {{\textbf {u}}})b_x-u_x)\right) }{|\varvec{B}|}\) and \(\beta _l = B_x u_l - \frac{\Delta Pb_x(2 b_l({\varvec{b}}\cdot {{\textbf {u}}})-u_l)}{|\varvec{B}|};~~\forall ~l\in \{y,z\}\)

\(\omega _1 = B_x - \frac{2 \Delta Pb_x (1-b_x^2)}{|\varvec{B}|}\) and \(\omega _l = B_l - \frac{\Delta Pb_l (1 - 2 b_x^2)}{|\varvec{B}|};~~\forall ~l\in \{y,z\}\)

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Singh, C., Yadav, A., Bhoriya, D. et al. Entropy Stable Finite Difference Schemes for Chew, Goldberger and Low Anisotropic Plasma Flow Equations. J Sci Comput 102, 51 (2025). https://doi.org/10.1007/s10915-024-02763-3

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