Black hole energy extraction via stationary scalar clouds
Abstract
We study scalar field configurations around Kerr black holes with a time-independent energy-momentum tensor. These stationary `scalar clouds', confined near the black hole (BH) by their own mass or a mirror at fixed radius, exist at the threshold for energy extraction via superradiance. Motivated by the electromagnetic Blandford-Znajek (BZ) mechanism, we explore whether scalar clouds could serve as a proxy for the force-free magnetosphere in the BZ process. We find that a stationary energy-extracting scalar cloud solution exists when the reflecting mirror is replaced by a semi-permeable surface which allows the cloud to radiate some energy to infinity while maintaining self-sustained superradiance. The radial energy flux displays the same behaviour for rapidly rotating holes as magnetohydrodynamic simulations predict for the BZ mechanism.
Keywords
Cite
@article{arxiv.1509.06681,
title = {Black hole energy extraction via stationary scalar clouds},
author = {Jordan Wilson-Gerow and Adam Ritz},
journal= {arXiv preprint arXiv:1509.06681},
year = {2016}
}
Comments
7 pages, 1 figure