黑洞喷流的精确引擎
An Exact Engine for Black-Hole Jets
- Sapienza Università di Roma（罗马大学）
- ICRANet（国际相对论天体物理中心网络）
- INAF – Osservatorio Astronomico d’Abruzzo（意大利国家天体物理研究所阿布鲁佐天文台）
- Marcel Grossmann Center（马塞尔·格罗斯曼中心）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文提出了黑洞喷流的精确引擎模型，揭示Blandford–Znajek机制并非精确解，证明稳态喷流不可能存在，确定喷流功率上限与黑洞衰变质量占比，完善了黑洞力学与喷流的理论框架。
AI中文摘要：
五十年来，Blandford–Znajek机制一直是一种机制而非精确解：在规定度规下的无作用力电动力学，喷流自身的场不产生影响。本文中，该场具有引力效应。分裂单极子的质量与磁单极子相当，因此其自引力对应磁Reissner–Nordström几何；两个分裂单极子跨越赤道电流片粘合，将黑洞、吸积盘和驱动喷流的磁场通量纳入同一时空，无作用力等离子体由此形成磁层。由此得出三个无测试场计算可观测的结论：第一，稳态喷流不可能存在，静止视界无法被加热，但滑移磁层必然加热视界，因此唯一的稳态是与黑洞共转的死态，而工作喷流是黑洞的衰变，其速率由场方程确定而非假设；第二，通量作为电荷进入黑洞力学定律，与自旋共享一个极值预算，该预算将喷流功率限制为$c^5/48G$，与质量无关；第三，寿命输出有限：最大自旋黑洞释放$1-e^{1/4}/\raw2=9.2\%$的质量，视界面积精确增长$\raw e$，视界自身的转动惯量随近喉道设定的无理指数$(\raw{17}-1)/2$消失，剩余的是角动量已转移至自身场的转动黑洞。
英文摘要：
For fifty years the Blandford--Znajek mechanism has been a mechanism and not an exact solution: force-free electrodynamics on a prescribed metric, with the jet's own field carrying no weight. Here that field gravitates. A split monopole weighs as much as a magnetic monopole, so its self-gravity is the magnetic Reissner--Nordström geometry; two copies glued across an equatorial current sheet put hole, disk and jet-driving flux into one spacetime, and force-free plasma makes a magnetosphere of it. Three things then follow that no test-field calculation can see. First, a steady jet is impossible. A stationary horizon cannot be heated but a slipping magnetosphere necessarily heats it, so the only stationary state is a dead one corotating with the hole, and a working jet is a black hole in decay at rates the field equations fix rather than assume. Second, flux enters the laws of black-hole mechanics as a charge, sharing one extremality budget with spin. That budget caps the jet power at $c^5/48G$ whatever the mass. Third, the lifetime output is finite: a maximally spinning hole delivers $1-e^{1/4}/\sqrt2=9.2\%$ of its mass and grows its horizon area by exactly $\sqrt e$. The horizon's own moment of inertia vanishes with the irrational exponent $(\sqrt{17}-1)/2$ set by the near-horizon throat, and what is left is a rotating hole whose angular momentum has passed to its own field.
