{"title":"Title: proton acceleration by kinetic turbulence across various magnetization levels in astrophysical plasmas","authors":"Ji-Hoon Ha","doi":"10.1007/s10509-024-04391-7","DOIUrl":null,"url":null,"abstract":"<div><p>Turbulence in astrophysical plasma transfers energy to kinetic scales, leading to proton acceleration or heating, yet the formation of suprathermal protons from such turbulence is not fully understood. While proton acceleration modeling based on the Fokker-Planck equation with diffusion through kinetic Alfvén waves (KAW) has been proposed to understand in-situ measurements of suprathermal protons in the interplanetary medium, more investigations using such modeling could help clarify the nature of particle acceleration in various astrophysical media beyond the interplanetary medium. Since the characteristics of KAW turbulence depend on the magnetization of the plasma system and the temperature anisotropy of the proton distribution function, proton acceleration mediated by KAW turbulence could also be influenced by these factors. By solving the Fokker-Planck equation, this study examines proton acceleration through KAW turbulence across strongly to weakly magnetized astrophysical plasmas, parameterized by plasma beta (<span>\\(\\beta =0.01-10\\)</span>), and the effects of proton temperature anisotropy. Particularly, our findings indicate that KAW turbulence significantly influences the presence of suprathermal protons in low-beta plasmas, such as the interplanetary medium, but is less impactful in high-beta environments, like the intergalactic and intracluster medium. Additionally, the proton temperature anisotropy significantly modulates the efficiency of proton diffusion in velocity space in low-beta environments.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"369 12","pages":""},"PeriodicalIF":1.8000,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Astrophysics and Space Science","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1007/s10509-024-04391-7","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Turbulence in astrophysical plasma transfers energy to kinetic scales, leading to proton acceleration or heating, yet the formation of suprathermal protons from such turbulence is not fully understood. While proton acceleration modeling based on the Fokker-Planck equation with diffusion through kinetic Alfvén waves (KAW) has been proposed to understand in-situ measurements of suprathermal protons in the interplanetary medium, more investigations using such modeling could help clarify the nature of particle acceleration in various astrophysical media beyond the interplanetary medium. Since the characteristics of KAW turbulence depend on the magnetization of the plasma system and the temperature anisotropy of the proton distribution function, proton acceleration mediated by KAW turbulence could also be influenced by these factors. By solving the Fokker-Planck equation, this study examines proton acceleration through KAW turbulence across strongly to weakly magnetized astrophysical plasmas, parameterized by plasma beta (\(\beta =0.01-10\)), and the effects of proton temperature anisotropy. Particularly, our findings indicate that KAW turbulence significantly influences the presence of suprathermal protons in low-beta plasmas, such as the interplanetary medium, but is less impactful in high-beta environments, like the intergalactic and intracluster medium. Additionally, the proton temperature anisotropy significantly modulates the efficiency of proton diffusion in velocity space in low-beta environments.
期刊介绍:
Astrophysics and Space Science publishes original contributions and invited reviews covering the entire range of astronomy, astrophysics, astrophysical cosmology, planetary and space science and the astrophysical aspects of astrobiology. This includes both observational and theoretical research, the techniques of astronomical instrumentation and data analysis and astronomical space instrumentation. We particularly welcome papers in the general fields of high-energy astrophysics, astrophysical and astrochemical studies of the interstellar medium including star formation, planetary astrophysics, the formation and evolution of galaxies and the evolution of large scale structure in the Universe. Papers in mathematical physics or in general relativity which do not establish clear astrophysical applications will no longer be considered.
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