Blandford-Znajek Trial

The Blandford-Znajek process is a mechanism for the extraction of energy from rotating black hole by electromagnetism . It was first described in 1977 by Roger Blandford and Roman Znajek .

As already described earlier in the Penrose process , the decisive place in the application of the mechanism is the ergosphere , i.e. the place around a rotating black hole in which the black hole forces all particles to rotate through the frame dragging effect . With a weak spin parameter, the ergosphere can be approximated as an ellipsoid of revolution that touches the event horizon at the poles of the black hole and becomes wider towards the equator. With magnetic fields from plasma in the accretion flow in the ergosphere, the morphology of the magnetic fields becomes toroidal and a toroidal magnetosphere is created. By increasing the field strength , a leptonic pair plasma of electrons and positrons , the so-called Penrose pair formation , can be generated in a cascade of incident gamma photons with photons that are trapped in photon orbit :

{\ displaystyle \ gamma + \ gamma \ longrightarrow e ^ {+} + e ^ {-}}

So the body that originally had the energy now has two sub-bodies, one of which has the negative energy and one has the positive energy , and consequently is. Since the negatively charged body falls into the black hole and the positively charged body leaves the ergosphere in the jets at the poles due to the gravitomagnetic force, energy is withdrawn from the rotating black hole. ${\ displaystyle E_ {0}}$ ${\ displaystyle E_ {n}}$ ${\ displaystyle E_ {p}}$ ${\ displaystyle E_ {p}> E_ {0}}$

Individual evidence

↑ M. Kafatos, D. Leiter: Penrose pair production as a power source of quasars and active galactic nuclei . In: The Astrophysical Journal . tape 229 , April 1, 1979, pp. 46-52 , doi : 10.1086 / 156928 .
^ RD Blandford, RL Znajek: Electromagnetic extraction of energy from Kerr black holes . In: Monthly Notices of the Royal Astronomical Society . tape 179 , no. 3 , January 7, 1977, p. 433-456 , doi : 10.1093 / mnras / 179.3.433 .

[1] M. Kafatos, D. Leiter: Penrose pair production as a power source of quasars and active galactic nuclei . In: The Astrophysical Journal . tape 229 , April 1, 1979, pp. 46-52 , doi : 10.1086 / 156928 .

[2] RD Blandford, RL Znajek: Electromagnetic extraction of energy from Kerr black holes . In: Monthly Notices of the Royal Astronomical Society . tape 179 , no. 3 , January 7, 1977, p. 433-456 , doi : 10.1093 / mnras / 179.3.433 .