Analytic force-free jet from disk-fed rotating black holes

Abstract

We present a new analytic model of force-free electromagnetic jet launched from a disk-fed rotating black hole. The jet solution is obtained through a systematic construction from previously developed methods. The resulting physical jet solution exhibits an asymptotically parabolic structure and is parametrized by the location of localized current concentration and sign reversal in the disk. We find, however, that the jet properties show negligible dependence on the disk parameter. The black hole jet captures the basic feature of the Blandford-Znajek mechanism for energy extraction and jet formation.

Figures (3)

• Figure 1: Poloidal field lines corresponding to (a) asymptotically parabolic and (b) asymptotically dipolar around a compact object (black-filled region). The solid red lines represents the thin disk, and the small orange circle marks the location of current concentration.
• Figure 2: Angular velocity (blue) and current (red) of the field lines for $d_{\circ} = r_{\text{ISCO}}$ (dashed lines) and $d_{\circ} \rightarrow \infty$ (solid lines) as functions of $X/X_{H}$. The angular velocity and current are insensitive to $d_{\circ}$.
• Figure 3: Inner (blue) and outer (orange) magnetic flux evaluated at $d_{\circ}$ for all the northern polar angles all using the same normalization $C$ derived in Appendix \ref{['apx.B']}. We used $d_{\circ} = 6M$ and $M =2$ in this plot.