Collisional Penrose process of extended test particles near an extremal Kerr black hole

TL;DR

This paper studies how the internal structure of extended test particles affects the energy extraction efficiency in the collisional Penrose process near extremal Kerr black holes, revealing dependencies on spin and quadrupolar parameters.

Contribution

It introduces a detailed analysis of the collisional Penrose process considering pole-dipole-quadrupole approximations, highlighting the impact of particle internal structure on energy extraction.

Findings

Maximum energy extraction depends on particle spin and quadrupolar parameters.

Efficiency decreases with increasing spin at fixed collision point.

Efficiency is higher when including quadrupolar effects compared to only dipolar.

Abstract

We investigate the collisional Penrose process of extended test particles near extremal Kerr black holes using the pole-dipole-quadrupole approximation. We analyze the motion of the test particles and examine the dynamics and maximum efficiency of energy extraction in this process. Our results demonstrate that the maximum extracted energy in the collisional Penrose process is influenced by the spin s and quadrupolar parameter CES2 of the test particles. Specifically, we observe that, at a fixed collisional position, the energy extraction efficiency decreases as the spin increases for either the pole-dipole or the pole-dipole-quadrupole approximation case. Furthermore, for a fixed spin, the energy extraction efficiency is higher in the pole-dipole-quadrupole approximation compared to the pole-dipole approximation. These findings provide insight into the role of the internal structures of the test particles in the collisional Penrose process.