Analytic dependence of particle acceleration efficiency on magnetohydrodynamic instability's growth parameters in Kerr black hole accretion disks.
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| Title: | Analytic dependence of particle acceleration efficiency on magnetohydrodynamic instability's growth parameters in Kerr black hole accretion disks. |
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| Authors: | Ha, Ji-Hoon1 (AUTHOR) hjhspace223@gmail.com |
| Source: | Astrophysics & Space Science. Feb2026, Vol. 371 Issue 2, p1-10. 10p. |
| Subjects: | Particle acceleration, Magnetohydrodynamic instabilities, Plasma pressure, Energy transfer, Accretion disks, Kerr black holes |
| Abstract: | Magnetohydrodynamic (MHD) instabilities in accretion disks play a crucial role in mediating energy transfer, and their physical properties have therefore been extensively investigated. In this study, we analytically examine particle acceleration driven by such instabilities in the accretion disk around a Kerr black hole, focusing on the regime where particles experience strong frame-dragging effects. Using the linear growth rate of the magnetorotational instability (MRI) obtained from general relativistic MHD analysis, we explore the dependence of the turbulent acceleration timescale on the MRI growth rate and the turbulent Alfvén Mach number. Because the MRI growth rate depends on the black hole spin, the pressure anisotropy with respect to the magnetic field, and the plasma beta, the acceleration timescale becomes shorter as these parameters increase. By incorporating the energy loss timescale, we estimate the maximum Lorentz factor of the particles where the acceleration and loss timescales are balanced. Furthermore, we solve the steady-state Fokker-Planck equation including both energy diffusion and radiative loss terms to obtain the particle energy distribution. The resulting steady-state spectra and mean particle energy clearly demonstrate that the particle acceleration efficiency increases with the MRI growth rate throughout the accretion disk, over a broad range of spin and plasma beta values. Our results suggest that higher spin and pressure anisotropy enhance particle energies, which could be relevant for understanding high-energy astrophysical phenomena in active galactic nuclei. [ABSTRACT FROM AUTHOR] |
| Copyright of Astrophysics & Space Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 192417897 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Analytic dependence of particle acceleration efficiency on magnetohydrodynamic instability's growth parameters in Kerr black hole accretion disks. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Ha%2C+Ji-Hoon%22">Ha, Ji-Hoon</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> hjhspace223@gmail.com</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Astrophysics+%26+Space+Science%22">Astrophysics & Space Science</searchLink>. Feb2026, Vol. 371 Issue 2, p1-10. 10p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Particle+acceleration%22">Particle acceleration</searchLink><br /><searchLink fieldCode="DE" term="%22Magnetohydrodynamic+instabilities%22">Magnetohydrodynamic instabilities</searchLink><br /><searchLink fieldCode="DE" term="%22Plasma+pressure%22">Plasma pressure</searchLink><br /><searchLink fieldCode="DE" term="%22Energy+transfer%22">Energy transfer</searchLink><br /><searchLink fieldCode="DE" term="%22Accretion+disks%22">Accretion disks</searchLink><br /><searchLink fieldCode="DE" term="%22Kerr+black+holes%22">Kerr black holes</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Magnetohydrodynamic (MHD) instabilities in accretion disks play a crucial role in mediating energy transfer, and their physical properties have therefore been extensively investigated. In this study, we analytically examine particle acceleration driven by such instabilities in the accretion disk around a Kerr black hole, focusing on the regime where particles experience strong frame-dragging effects. Using the linear growth rate of the magnetorotational instability (MRI) obtained from general relativistic MHD analysis, we explore the dependence of the turbulent acceleration timescale on the MRI growth rate and the turbulent Alfvén Mach number. Because the MRI growth rate depends on the black hole spin, the pressure anisotropy with respect to the magnetic field, and the plasma beta, the acceleration timescale becomes shorter as these parameters increase. By incorporating the energy loss timescale, we estimate the maximum Lorentz factor of the particles where the acceleration and loss timescales are balanced. Furthermore, we solve the steady-state Fokker-Planck equation including both energy diffusion and radiative loss terms to obtain the particle energy distribution. The resulting steady-state spectra and mean particle energy clearly demonstrate that the particle acceleration efficiency increases with the MRI growth rate throughout the accretion disk, over a broad range of spin and plasma beta values. Our results suggest that higher spin and pressure anisotropy enhance particle energies, which could be relevant for understanding high-energy astrophysical phenomena in active galactic nuclei. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Astrophysics & Space Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1007/s10509-026-04545-9 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 10 StartPage: 1 Subjects: – SubjectFull: Particle acceleration Type: general – SubjectFull: Magnetohydrodynamic instabilities Type: general – SubjectFull: Plasma pressure Type: general – SubjectFull: Energy transfer Type: general – SubjectFull: Accretion disks Type: general – SubjectFull: Kerr black holes Type: general Titles: – TitleFull: Analytic dependence of particle acceleration efficiency on magnetohydrodynamic instability's growth parameters in Kerr black hole accretion disks. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Ha, Ji-Hoon IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 02 Text: Feb2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 0004640X Numbering: – Type: volume Value: 371 – Type: issue Value: 2 Titles: – TitleFull: Astrophysics & Space Science Type: main |
| ResultId | 1 |
