Journal of Experimental and Theoretical PhysicsJournal of Experimental and Theoretical Physics0044-45103034-641XRussian Academy of Science10.7868/S3034641X25110128ELECTRON ACCELERATION VIA LOWER-HYBRID DRIFT INSTABILITY IN ASTROPHYSICAL PLASMAS: DEPENDENCE ON PLASMA BETA AND SUPRATHERMAL ELECTRON DISTRIBUTIONSELECTRON ACCELERATION VIA LOWER-HYBRID DRIFT INSTABILITY IN ASTROPHYSICAL PLASMAS: DEPENDENCE ON PLASMA BETA AND SUPRATHERMAL ELECTRON DISTRIBUTIONSHaJi-HoonHaJi-Hoon ha_ji-hoon_noemail@ras.ruVolnovaE.S.VolnovaE.S. volnova_es_noemail@ras.ruKorea Space Weather Center 63025Korea Space Weather Center 63025Institute for Basic Science 34126Institute for Basic Science 34126060220261685708719

Density inhomogeneities are ubiquitous in space and astrophysical plasmas, particularly at magnetic reconnection sites, shock fronts, and within compressible turbulence. The gradients associated with these inhomogeneous plasma regions serve as free energy sources that can drive plasma instabilities, including the lower-hybrid drift instability (LHDI). Notably, lower-hybrid waves are frequently observed in magnetized space plasma environments, such as Earth's magnetotail and magnetopause. Previous studies have primarily focused on modeling particle acceleration via LHDI in these regions using a quasilinear approach. This study expands the investigation of LHDI to a broader range of environments, spanning weakly to strongly magnetized media, including interplanetary, interstellar, intergalactic, and intracluster plasmas. To explore the applicability of LHDI in various astrophysical settings, we employ two key parameters: (1) plasma magnetization, characterized by the plasma beta parameter, and (2) the spectral slope of suprathermal electrons following a power-law distribution. Using a quasilinear model, we determine the critical values of plasma beta and spectral slope that enable efficient electron acceleration via LHDI by comparing the rate of growth of instability and the damping rate of the resulting fluctuations. We further analyze the time evolution of the electron distribution function to confirm these critical conditions. Our results indicate that electron acceleration is generally most efficient in low-beta plasmas (1). Finally, we discuss the astrophysical implications of our findings, highlighting the role of LHDI in electron acceleration across diverse plasma environments.

Density inhomogeneities are ubiquitous in space and astrophysical plasmas, particularly at magnetic reconnection sites, shock fronts, and within compressible turbulence. The gradients associated with these inhomogeneous plasma regions serve as free energy sources that can drive plasma instabilities, including the lower-hybrid drift instability (LHDI). Notably, lower-hybrid waves are frequently observed in magnetized space plasma environments, such as Earth's magnetotail and magnetopause. Previous studies have primarily focused on modeling particle acceleration via LHDI in these regions using a quasilinear approach. This study expands the investigation of LHDI to a broader range of environments, spanning weakly to strongly magnetized media, including interplanetary, interstellar, intergalactic, and intracluster plasmas. To explore the applicability of LHDI in various astrophysical settings, we employ two key parameters: (1) plasma magnetization, characterized by the plasma beta parameter, and (2) the spectral slope of suprathermal electrons following a power-law distribution. Using a quasilinear model, we determine the critical values of plasma beta and spectral slope that enable efficient electron acceleration via LHDI by comparing the rate of growth of instability and the damping rate of the resulting fluctuations. We further analyze the time evolution of the electron distribution function to confirm these critical conditions. Our results indicate that electron acceleration is generally most efficient in low-beta plasmas (1). Finally, we discuss the astrophysical implications of our findings, highlighting the role of LHDI in electron acceleration across diverse plasma environments.

J. Giacalone, Astrophys. J. 609, 452 (2004).M. Scholer and D. Burgess, Phys. Plasmas 14, 072103 (2007).T. Umeda, Y. Kidani, S. Matsukiyo, and R. Yamazaki, J. Geophys. Res.: Space Phys. 117, A03206 (2012).D. Caprioli and A. Spitkovsky, Astrophys. J. 794, 46 (2014).S. Kim, J.-H. Ha, D. Ryu, and H. Kang, Astrophys. J. 892, 85 (2020).S. Kim, J.-H. Ha, D. Ryu, and H. Kang, Astrophys. J. 913, 35 (2021).L. Orusa and D. Caprioli, Phys. Rev. Lett. 131, 095201 (2023).R. Vainio, L. Kocharov, and T. Laitinen, Astrophys. J. 528, 1015 (2000).V. N. Zirakashvili, V. S. Ptuskin, and H. J. Volk, Astrophys. J. 678, 255 (2008).A. M. Bykov, D. C. Ellison, S. M. Osipov, and A. E. Vladimirov, Astrophys. J. 789, 137 (2014).J.-H. Ha, D. Ryu, and H. Kang, Astrophys. J. 907, 26 (2021).J.-H. Ha, Astrophys. 67, 330 (2024a).J.-H. Ha, Astrophys. Space Sci. 369, 126 (2024b).J.-H. Ha, Zh. Exp. Teor. Fiz. 167, 129 (2025).N. A. Krall and P. C. Liewer, Phys. Rev. A 4, 2094 (1971).R. C. Davidson, N. T. Gladd, C. S. Wu, and J. D. Huba, Phys. Fluids 20, 301 (1977).S. D. Bale, F. S. Mozer and T. Phan, Geophys. Res. Lett. 29, 2180 (2002).D. B. Graham, Y. V. Khotyaintsev, C. Norgren et al., J. Geophys. Res.: Space Phys. 124, 8727 (2019).J. Yoo, J.-Y. Ji, M. V. Ambat et al., Geophys. Res. Lett. 47, e87192 (2020).J. Ng, J. Yoo, L. J. Chen, N. Bessho, and H. Ji, Phys. Plasmas 30, 042101 (2023).Y. Ren, L. Dai, C. Wang, and Z. Guo, Astrophys. J. 956, 143 (2023).D. B. Graham, Y. V. Khotyaintsev, C. Norgren et al., J. Geophys. Res.: Space Phys. 122, 517 (2017).M. Zhou, J. Berchem, R. J. Walker et al., J. Geophys. Res.: Space Phys. 123, 1834 (2018).B.-B. Tang, W. Y. Li, D. B. Graham et al., Geophys. Res. Lett. 47, e89880 (2020).Y. Ren, L. Dai, C. Wang, and B. Lavraud, Astrophys. J. 928, 5 (2022).S. N. Walker, M. A. Balikhin, H. S. C. K. Alleyne et al., Annal. Geophys. 26, 699 (2008).V. V. Krasnoselskikh, E. N. Kruchina, A. S. Volokitin, and G. Thejappa, Astron. Astrophys. 149, 323 (1985).Y. Zhang and H. Matsumoto, J. Geophys. Res.: Space Phys. 103, 20561 (1998).L. B. Wilson, A. Koval, A. Szabo et al., J. Geophys. Res.: Space Phys. 118, 5 (2013).Y. V. Khotyaintsev, C. M. Cully, A. Vaivads, M. Andre, and C. J. Owen, Phys. Rev. Lett. 106, 165001 (2011).D.-X. Pan, Y. V. Khotyaintsev, D. B. Graham et al., Geophys. Res. Lett. 45, 116 (2018).K. G. McClements, R. Bingham, J. J. Su, J. M. Dawson, and D. S. Spicer, Astrophys. J. 409, 465 (1993).I. H. Cairns and B. F. McMillan, Phys. Plasmas 12, 102110 (2005).F. Lavorenti, P. Henri, F. Califano, S. Aizawa, and N. Andre, Astron. Astrophys. 652, A20 (2021).E. N. Fadeev, A. S. Andrianov, M. S. Burgin et al., Monthly Notices of the Royal Astron. Soc. 480, 4199 (2018).M. V. Popov and T. V. Smirnova, Astron. Rep. 65, 1129 (2021).D. Martizzi, C.-A. Faucher-Giguere, and E. Quataert, Monthly Notices of the Royal Astron. Soc. 450, 504 (2015).C. F. McKee, Proc. IAU Colloquium 101, Cambridge University Press, 205 (1988).M. Markevitch, T. J. Ponman, P. E. J. Nulsen et al., Astrophys. J. 541, 542 (2000).M. Markevitch and A. Vikhlinin, Phys. Rep. 443, 1 (2007).H. Bourdin, P. Mazzotta, M. Markevitch, S. Giacintucci, and G. Brunetti, Astrophys. J. 764, 82 (2013).J. ZuHone and E. Roediger, J. Plasma Phys. 82, 535820301 (2016).J.-H. Ha, D. Ryu, and H. Kang, Astrophys. J. 857, 26 (2018).S. Roh, D. Ryu, H. Kang, S. Ha, and H. Jang, Astrophys. J. 883, 138 (2019).R. Xu, D. Caprioli and A. Spitkovsky, Astrophys. J. Lett. 897, L41 (2020).Y. Kawazura, M. Barnes, A. A. Schekochihin et al., Proc. of the National Academy of Sciences 116, 771 (2019).J. Squire, R. Meyrand, and M. W. Kunz, Astrophys. J. Lett. 957, L30 (2023).M. A. Shay, C. C. Haggerty, T. D. Phan et al., Phys. Plasmas 21, 122902 (2014).C. C. Haggerty, M. A. Shay, J. F. Drake et al., Geophy. Res. Lett. 42, 9657 (2015).M. Hoshino, Astrophys. J. Lett. 868, L18 (2018).W. Baumjohann, G. Paschmann, and C. A. Cattell, J. Geophys. Res. 94, 6597 (1989).C.-P. Wang, M. Gkioulidou, L. R. Lyons, and V. Angelopoulos, J. Geophys. Res.: Space Phys. 117, A08215 (2012).J. P. Eastwood, T. D. Phan, J. F. Drake et al., Phys. Rev. Lett. 110, 225001 (2013).C. E. Rakowski, Adv. Space Res. 35, 1017 (2005).J. C. Raymond and K. E. Korreck, AIP Conf. Proc. 781, 342 (2005).P. Ghavamian, J. M. Laming, and C. E. Rakowski, Astrophys. J. 654, L69 (2007).S. J. Schwartz, M. F. Thomsen, S. J. Bame, and J. Stansberry, J. Geophys. Res. 93, 12923 (1988).C. T. Russell, AIP Conf. Proc. 781, 3 (2005).H. R. Russell, B. R. McNamara, J. S. Sanders et al., Monthly Notices of the Royal Astron. Soc. 423, 236 (2012).S. Ettori and A. C. Fabian, Monthly Notices of the Royal Astron. Soc. 293, L33 (1998).M. Takizawa, Astrophys. J. 509, 579 (1998).