AI 中文总结
研究针对中子星相关天体物理现象中理想磁流体动力学近似的局限，扩展BAM代码纳入电阻性广义相对论磁流体动力学描述，经多种测试验证，发现非理想效应影响，凸显其对模拟合并后残余物演化的重要性，为后续研究奠基。
AI 中文摘要
许多天体物理现象，如脉冲星和短伽马射线暴，与中子星和中子星合并中存在的极强磁场有关。理想磁流体动力学近似无法捕捉非理想过程。为此，我们扩展了数值相对论代码BAM，纳入电阻性广义相对论磁流体动力学描述。通过一系列特殊相对论磁流体动力学基准测试及对孤立和双星中子星系统的稳定模拟进行验证。研究了有限电导率对磁场放大、质量喷射和非理想广义相对论磁流体动力学效应的影响。发现平行于磁场的电场分量在理想情况下为零，在非理想情况下可达总电场强度的10%。强调了非理想效应在准确模拟合并后残余物长期演化中的潜在重要性，为未来采用更现实微观物理学的研究铺平了道路。
英文摘要
Many astrophysical phenomena, including pulsars and short gamma-ray bursts, are associated with the extremely strong magnetic fields present in neutron stars and neutron star mergers. While the ideal magnetohydrodynamic approximation, which assumes infinite conductivity, provides an excellent description of the neutron-star interior, it cannot capture non-ideal processes such as Ohmic dissipation and magnetic reconnection. To overcome this limitation, we present an extension of the numerical-relativity code BAM incorporating a resistive general-relativistic magnetohydrodynamic (GRMHD) description. We validate the new implementation through an extensive suite of special-relativistic magnetohydrodynamic benchmark tests and by performing stable simulations of isolated and binary neutron star systems. For the latter, we investigate the impact of finite conductivity on magnetic-field amplification, mass ejection, and non-ideal GRMHD effects. In particular, we find that the component of the electric field parallel to the magnetic field, which is zero in the ideal case, can reach up to 10% of the total electric field strength. This highlights the potential importance of non-ideal effects for accurately modeling the long-term evolution of post-merger remnants, particularly in low-density regions. Although the present study is restricted to simplified piecewise-polytropic equations of state, it demonstrates the capabilities of the new resistive GRMHD framework and paves the way for future investigations employing more realistic microphysics.
Comments27 pages, 28 figures
