The Penrose process in rotating regular black holes

Abstract

We investigate the Penrose process of energy extraction in the context of rotating regular black holes. Previously known geometries, as well as a new rotating regular black hole generated from a recently proposed (Gen. Rel. Grav. 56, 52 (2024)) non-rotating, seed solution are considered in our analysis of energy extraction. For the known Neves–Saa class of rotating regular black hole solutions, which includes the Bardeen, Hayward and Fan–Wang spacetimes as special cases, the extraction efficiency is bounded above by the known value for the singular Kerr spacetime. However, in the case of the new rotating regular black hole, which does not have a Schwarzschild singular limit for zero rotation, the extraction efficiency can indeed become much larger, as evident through our results here. Here too, the highest efficiency occurs for the singular solution. Thus, expectedly, both the regularisation parameter in the metric functions, as well as the character of the seed non-rotating solution influence the extent of energy extraction, relative to the respective singular scenarios.