To delve into the enigma of black holes, scientists from Tohoku University have developed a highly detailed simulation of turbulence within accretion disks, achieving the highest level of resolution to date.
A team of researchers from Tohoku University and Utsunomiya University has made significant advances in grasping the complicated nature of turbulence occurring in “accretion disks,” which are the gas-filled structures orbiting around black holes. By leveraging cutting-edge supercomputers, they conducted simulations with unprecedented detail.
Scientists are keenly interested in the strange and extreme characteristics of black holes. However, since black holes trap light, they cannot be directly seen using telescopes. Instead, researchers examine the influence black holes have on their nearby environment. Accretion disks provide a means to indirectly observe black holes, as they emit electromagnetic radiation detectable by telescopes.
“Simulating the behavior of accretion disks with accuracy significantly enhances our comprehension of the physical dynamics surrounding black holes,” states Yohei Kawazura. “It offers essential insights that help us interpret data gathered from the Event Horizon Telescope.”
The team employed powerful supercomputers, including RIKEN’s “Fugaku” (recognized as the world’s fastest computer until 2022) and NAOJ’s “ATERUI II,” to conduct simulations with remarkable levels of detail. Although prior numerical simulations of accretion disks existed, none successfully observed the inertial range due to limited computational capabilities. This particular study marks the first successful reproduction of the “inertial range,” which connects large and small turbulent eddies within accretion disk turbulence.
Additionally, researchers found that “slow magnetosonic waves” are the primary type of wave present within this inertial range. This discovery helps explain the selective heating of ions within accretion disks. The turbulent electromagnetic fields interacting with charged particles within these disks can potentially accelerate some particles to extremely high energies.
In the field of magnetohydrodynamics, basic wave types include slow and fast magnetosonic waves as well as Alfvén waves. The research revealed that slow magnetosonic waves dominate the inertial range, carrying approximately twice the energy of Alfvén waves. Moreover, this work underscores a key distinction between turbulence in accretion disks and that of solar wind, where Alfvén waves are prevalent.
This progress is anticipated to refine how observational data from radio telescopes, specifically those focused on areas near black holes, is understood and interpreted.
The findings were published in Science Advances on August 28, 2024.
