Magnetic reconnection as a mechanism for energy extraction from rotating black holes

Spinning black holes store rotational energy that can be extracted. When a hole is immersed in an externally supplied magnetic field, reconnection of field lines within the ergosphere generate negative (relative to infinity) particles fall into event horizon while other escape stealing from hole. We show analytically extraction via possible when spin high (dimensionless $a\sim1$) and plasma strongly magnetized (plasma magnetization $\sigma_0>1/3$). The parameter space region where allowed depends on orientation reconnecting lines. For $\sigma_0 \gg 1$, asymptotic at infinity per enthalpy decelerated swallowed by maximally rotating found $\epsilon^\infty_- \simeq - \sqrt{\sigma_0/3}$. accelerated escapes takes away asymptotes $\epsilon^\infty_+ \sqrt{3\sigma_0}$. maximum power extracted escaping $P_{\rm extr}^{\rm max} \sim 0.1 M^2\sqrt{\sigma_0}\,w_0$ (here, $M$ mass $w_0$ density) for collisionless regime one order magnitude lower collisional regime. Energy causes significant spindown $a 1$. efficiency energization process $\eta_{\rm 3/2$. Since fast should occur intermittently scenario proposed here, associated emission few gravitational radii expected display bursty nature.