title: Kelvin-Helmholtz versus Hall magnetoshear instability in astrophysical flows.
abstract: We study the stability of shear flows in a fully ionized plasma. Kelvin-Helmholtz is a well-known macroscopic and ideal shear-driven instability. In sufficiently low-density plasmas, also the microscopic Hall magnetoshear instability can take place. We performed three-dimensional simulations of the Hall-magnetohydrodynamic equations where these two instabilities are present, and carried out a comparative study. We find that when the shear flow is so intense that its vorticity surpasses the ion-cyclotron frequency of the plasma, the Hall magnetoshear instability is not only non-negligible, but it actually displays growth rates larger than those of the Kelvin-Helmholtz instability.
authors.affiliation: Instituto de Astronomía y Física del Espacio, C.C. 67 Suc. 28, 1428 Buenos Aires, Argentina.
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Gómez
authors.forename: Cecilia
authors.initials: C
authors.lastname: Bejarano
authors.affiliation: Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires & Instituto de Física de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Argentina.
authors.forename: Pablo D
authors.initials: PD
authors.lastname: Mininni