| Name: | Chandrachur Chakraborty |
| Affiliation: | Manipal Centre for Natural Sciences, Manipal Academy of Higher Education, INDIA |
| Conference ID : | ASI2024_121 |
| Title : | Magnetic Penrose process in the magnetized Kerr spacetime: a possible source of ultrahigh-energy cosmic rays |
| Authors : | Chandrachur Chakraborty |
| Authors Affiliation: | Manipal Centre for Natural Sciences, Manipal Academy of Higher Education, Manipal 576104, INDIA |
| Mode of Presentation: | Poster |
| Abstract Category : | High Energy Phenomena, Fundamental Physics and Astronomy |
| Abstract : | Efficiency of the magnetic Penrose process (MPP) could exceed 100% for extracting the energy from a Kerr black hole, if it is immersed in a mG order magnetic field. Considering the magnetized Kerr spacetime, I shall discuss the exact expression of efficiency for MPP, which is valid for both the Kerr black hole (BH) and Kerr superspinar (SS), and also from the weak magnetic field to an ultra-strong magnetic field. I show that although the value of efficiency increases upto a certain value of ultra-strong magnetic field, it decreases to zero beyond that in case of the Kerr BHs. On the other hand, efficiency shows the opposite behavior in case of the Kerr SSs. One intriguing feature that emerges is, MPP efficiency acquires the maximum value for the Kerr parameter a~0.786, decreases for the range 0.7860.786, and is fully expelled from the extremal Kerr BH due to the gravitational Meissner effect. I shall also discuss the ordinary Penrose process (PP) for the magnetized Kerr spacetime, and show that the MPP for Kerr BHs, Kerr SSs and the ordinary PP for Kerr SSs can be superefficient for the astrophysical applications to powering engines in the high-energy sources like active galactic nuclei and quasars, in the weak magnetic fields. MPP in the magnetized Kerr spacetime could also be the origin of ultrahigh-energy (~ 10^20 eV) cosmic rays received on Earth, as the MPP efficiency could reach maximum ∼ 10^22 % for a magnetized Kerr BH. It is almost impossible to extract energy from a BH (SS) through MPP (PP) in the ultra-strong magnetic fields. |
