Description
The terrestrial bow shock is a collisionless plasma discontinuity that converts directed solar-wind energy into downstream thermal, magnetic, turbulent, and nonthermal particle energy before the flow reaches the magnetopause. This study reengineers a magnetohydrodynamic solar-wind-magnetosphere model into an explicitly multiscale framework in which global boundary dynamics, kinetic electron heating, and the relativistic Dirac parent theory are connected without conflating their domains of validity. The macroscopic sector retains ideal MHD, complete Rankine-Hugoniot jump relations, oblique fast-mode propagation, Parker-spiral IMF geometry, dipolar pressure balance, Shue-type magnetopause geometry, Farris-Russell bow-shock standoff physics, reconnection electric fields, plasma beta, temperature anisotropy, and uncertainty propagation. The microscopic extension introduces the electromagnetic four-potential and field tensor, Dirac gamma and Pauli matrices, gauge-covariant coupling, conserved four-current, relativistic dispersion, and the low-energy Foldy-Wouthuysen/Pauli limit. A 120-minute physics-constrained synthetic event, retained from the preceding computational manuscript and explicitly identified as simulated, is used to reproduce OMNI-like upstream variability. Six paired publication-quality figures quantify global compression, shock jumps, geometry, magnetosheath heating, IMF coupling, relativistic corrections, and spin-energy scales. The calculations show that the MHD/kinetic description controls ordinary terrestrial bow-shock dynamics, while the Dirac sector provides a rigorous parent theory for spin-1/2 electrons. Under typical near-Earth magnetic fields and electron temperatures, both the relativistic parameter K_e/(m_e c^2 ) and the spin-to-thermal ratio μ_B B/(k_B T_e ) are very small, establishing quantitatively why Dirac corrections should not be misidentified as the principal mechanism of global bow-shock formation. The resulting framework is suitable for direct replacement of the synthetic driver with bow-shock-nose-shifted OMNI data and local MMS crossings.
| Title | Multiscale MHD, Kinetic, and Dirac-Pauli Modeling of Solar-Wind-Magnetosphere Bow-Shock Dynamics |
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