Energy extraction-driven instability and horizon formation in Kerr-Newman naked singularities and their limiting cases
Energy extraction-driven instability and horizon formation in Kerr-Newman naked singularities and their limiting cases
Vishva Patel
AbstractEnergy extraction from compact objects has been a central topic in general relativity since the introduction of the Penrose process. In this work we present a unified analysis of rotational and electromagnetic energy extraction in Kerr, Reissner-Nordstrom, and Kerr-Newman spacetimes. Using particle energetics and the irreducible mass formalism, we compare the efficiencies of these mechanisms and examine their consequences for horizonless objects. While purely rotational extraction in Kerr spacetime is fundamentally limited by geometric constraints, electromagnetic interactions enlarge the region of negative energy orbits through an effective ergoregion, allowing significantly higher efficiencies. In Kerr-Newman geometry, the combined effect of rotation and charge further enhances the extractable energy. We then study the long-term evolution of over-extremal cases under continuous extraction. By deriving coupled evolution equations for the mass, spin, and charge parameters, we show that continuous extraction can gradually drive a naked singularity toward the extremal bound. For astrophysically realistic luminosities, the characteristic evolution timescale is of order about 10^9 years. These results suggest that energy extraction provides an energetic indication of instability in Reissner-Nordstrom, Kerr, and Kerr-Newman naked singularities and may lead to horizon formation as a long-term stabilizing outcome.