Electron-scale Kelvin-Helmholtz Instability In Magnetized Shear Flows

Electron-scale Kelvin-Helmholtz instabilities (ESKHI) are found in a number of astrophysical situations. Naturally ESKHI is subject to a background magnetic subject, however an analytical dispersion relation and Wood Ranger official an accurate progress rate of ESKHI beneath this circumstance are long absent, as former MHD derivations are not relevant within the relativistic regime. We present a generalized dispersion relation of ESKHI in relativistic magnetized shear flows, Wood Ranger official with few assumptions. ESKHI linear growth rates in certain instances are numerically calculated. We conclude that the presence of an external magnetic subject decreases the maximum instability growth fee most often, cordless Wood Ranger Power Shears review shears but can slightly improve it when the shear velocity is sufficiently excessive. Also, Wood Ranger Power Shears USA Wood Ranger Power Shears specs Wood Ranger Power Shears coupon Wood Ranger Power Shears sale manual the external magnetic subject results in a larger cutoff wavenumber of the unstable band and Wood Ranger official will increase the wavenumber of the most unstable mode. PIC simulations are carried out to confirm our conclusions, where we also observe the suppressing of kinetic DC magnetic field era, resulting from electron gyration induced by the external magnetic discipline. Electron-scale Kelvin-Helmholtz instability (ESKHI) is a shear instability that takes place on the shear boundary the place a gradient in velocity is current.



Despite the importance of shear instabilities, ESKHI was only acknowledged recently (Gruzinov, 2008) and stays to be largely unknown in physics. KHI is stable below a such situation (Mandelker et al., 2016). These make ESKHI a promising candidate to generate magnetic fields in the relativistic jets. ESKHI was first proposed by Gruzinov (2008) in the restrict of a chilly and collisionless plasma, the place he additionally derived the analytical dispersion relation of ESKHI progress charge for symmetrical shear flows. PIC simulations later confirmed the existence of ESKHI (Alves et al., 2012), finding the technology of typical electron vortexes and magnetic subject. It is noteworthy that PIC simulations also found the technology of a DC magnetic area (whose common along the streaming path just isn't zero) in firm with the AC magnetic discipline induced by ESKHI, while the previous will not be predicted by Gruzinov. The generation of DC magnetic fields is because of electron thermal diffusion or mixing induced by ESKHI throughout the shear interface (Grismayer et al., 2013), which is a kinetic phenomenon inevitable in the settings of ESKHI.



A transverse instability labelled mushroom instability (MI) was also discovered in PIC simulations concerning the dynamics within the plane transverse to the velocity shear (Liang et al., 2013a; Alves et al., 2015; Yao et al., 2020). Shear flows consisting of electrons and positrons are also investigated (Liang et al., 2013a, b, 2017). Alves et al. ESKHI and numerically derived the dispersion relation within the presence of density contrasts or clean velocity shears (Alves et al., 2014), Wood Ranger official which are both found to stabilize ESKHI. Miller & Rogers (2016) prolonged the idea of ESKHI to finite-temperature regimes by considering the strain of electrons and derived a dispersion relation encompassing both ESKHI and MI. In natural eventualities, ESKHI is usually subject to an external magnetic area (Niu et al., 2025; Jiang et al., 2025). However, works talked about above had been all carried out within the absence of an external magnetic field. While the idea of fluid KHI has been prolonged to magnetized flows a long time ago (Chandrasekhar, 1961; D’Angelo, 1965), the conduct of ESKHI in magnetized shear flows has been somewhat unclear.



Thus far, the only theoretical concerns regarding this downside are introduced by Che & Zank (2023) and Tsiklauri (2024). Both works are limited to incompressible plasmas and Wood Ranger official some type of MHD assumptions, that are only legitimate for small shear velocities. Therefore, their conclusions can't be straight applied within the relativistic regime, the place ESKHI is predicted to play a major role (Alves et al., 2014). Simulations had reported clear discrepancies from their principle (Tsiklauri, 2024). As Tsiklauri highlighted, a derivation of the dispersion relation with out excessive assumptions is critical. This forms a part of the motivation behind our work. On this paper, we are going to consider ESKHI under an external magnetic field by immediately extending the works of Gruzinov (2008) and Alves et al. 2014). Because of this our work is carried out in the limit of cold and collisionless plasma. We adopt the relativistic two-fluid equations and keep away from any form of MHD assumptions. The paper is organized as follows. In Sec. 1, Wood Ranger official we current a brief introduction to the background and subject of ESKHI.